ORCID Profile
0000-0003-3542-3874
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Nanotechnology | Nanophotonics | Nanomaterials | Functional Materials | Materials Engineering | Condensed Matter Physics | Biological Physics | Manufacturing Engineering | Manufacturing Processes and Technologies (excl. Textiles) | Metals and Alloy Materials | Nanoscale Characterisation | Nanomanufacturing | Nanofabrication, Growth and Self Assembly | Manufacturing engineering | Nanotechnology | Optical Properties of Materials | Synthesis of Materials | Sensor Technology (Chemical aspects) | Photodetectors, Optical Sensors and Solar Cells | Manufacturing processes and technologies (excl. textiles) | Lasers and quantum electronics | Machine tools | Medical Biotechnology | Microtechnology | Medical Biotechnology Diagnostics (incl. Biosensors) | Nonlinear Optics and Spectroscopy | Optics And Opto-Electronic Physics | Condensed Matter Physics—Structural Properties | Medical Devices | Macromolecular and Materials Chemistry | Transport Properties and Non-Equilibrium Processes | Structural Chemistry and Spectroscopy | Nanomedicine | Quantum Optics | Surfaces and Structural Properties of Condensed Matter | Electronic and Magnetic Properties of Condensed Matter; Superconductivity | Environmental Nanotechnology | Nanobiotechnology | Condensed Matter Characterisation Technique Development | Nanoelectronics
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Physical Sciences | Expanding Knowledge in Engineering | Integrated Circuits and Devices | Expanding Knowledge in Technology | Emerging Defence Technologies | Solar-Photovoltaic Energy | Expanding Knowledge in the Chemical Sciences | Scientific Instruments | Education and Training Systems not elsewhere classified | National Security | Occupational Health | Coated Metal and Metal-Coated Products | Other | Metals (e.g. Composites, Coatings, Bonding) | Manufacturing not elsewhere classified | Diagnostic Methods | Expanding Knowledge in the Earth Sciences | Medical Instruments | Expanding Knowledge in the Biological Sciences | Health Status (e.g. Indicators of Well-Being) |
Related Links
Publications
Engineering gold alloys for plasmonics
Publisher: Springer Science and Business Media LLC
Date: 03-09-2014
Preface: International Conference on Holography Meets Advanced Manufacturing (HMAM2)
Publisher: MDPI
Date: 24-07-2023
Light-induced reflectivity transients in black-Si nanoneedles
Publisher: Elsevier BV
Date: 2016
Phase Transformation in Laser-Induced Micro-Explosion in Olivine (Fe,Mg)2SiO4
Publisher: Wiley
Date: 31-03-2014
Dual THz wave and X-ray generation from a water film under femtosecond laser excitation
Publisher: MDPI AG
Date: 13-07-2018
DOI: 10.3390/NANO8070523
Abstract: Simultaneous emission of the THz wave and hard X-ray from thin water free-flow was induced by the irradiation of tightly-focused femtosecond laser pulses (35 fs, 800 nm, 500 Hz) in air. Intensity measurements of the THz wave and X-ray were carried out at the same time with time-domain spectroscopy (TDS) based on electro-optic s ling with a ZnTe(110) crystal and a Geiger counter, respectively. Intensity profiles of the THz wave and X-ray emission as a function of the solution flow position along the incident laser axis at the laser focus show that the profile width of the THz wave is broader than that of the X-ray. Furthermore, the profiles of the THz wave measured in reflection and transmission directions show different features and indicate that THz wave emission is, under single-pulse excitation, induced mainly in laser-induced plasma on the water flow surface. Under double-pulse excitation with a time separation of 4.6 ns, 5–10 times enhancements of THz wave emission were observed. Such dual light sources can be used to characterise materials, as well as to reveal the sequence of material modifications under intense laser pulses.
Enhancement of X-ray emission from nanocolloidal gold suspensions under double-pulse excitation
Publisher: Beilstein Institut
Date: 10-2018
DOI: 10.3762/BJNANO.9.242
Abstract: Enhancement of X-ray emission was observed from a micro-jet of a nano-colloidal gold suspension in air under double-pulse excitation of ultrashort (40 fs) near-IR laser pulses. Temporal and spatial overlaps between the pre-pulse and the main pulse were optimized for the highest X-ray emission. The maximum X-ray intensity was obtained at a 1–7 ns delay of the main pulse irradiation after the pre-pulse irradiation with the micro-jet position shifted along the laser beam propagation. It was revealed that the volume around gold nanoparticles where the permittivity is near zero, ε ≈ 0, accounts for the strongest absorption, which leads to the effective enhancements of X-ray emission.
THz Filters Made by Laser Ablation of Stainless Steel and Kapton Film
Publisher: MDPI AG
Date: 25-07-2022
DOI: 10.3390/MI13081170
Abstract: THz band-pass filters were fabricated by femtosecond-laser ablation of 25-μm-thick micro-foils of stainless steel and Kapton film, which were subsequently metal coated with a ∼70 nm film, closely matching the skin depth at the used THz spectral window. Their spectral performance was tested in transmission and reflection modes at the Australian Synchrotron’s THz beamline. A 25-μm-thick Kapton film performed as a Fabry–Pérot etalon with a free spectral range (FSR) of 119 cm−1, high finesse Fc≈17, and was tuneable over ∼10μm (at ∼5 THz band) with β=30∘ tilt. The structure of the THz beam focal region as extracted by the first mirror (slit) showed a complex dependence of polarisation, wavelength and position across the beam. This is important for polarisation-sensitive measurements (in both transmission and reflection) and requires normalisation at each orientation of linear polarisation.
Fluorescence Colour Control in Perylene-Labeled Polymer Chains Trapped by Nanotextured Silicon.
Publisher: Wiley
Date: 27-01-2022
Abstract: The ability to modulate, tune, and control fluorescence colour has attracted much attention in photonics-related research fields. Thus far, it has been impossible to achieve fluorescence colour control (FCC) for material with a fixed structure, size, surrounding medium, and concentration. Here, we propose a novel approach to FCC using optical tweezers. We demonstrate an optical trapping technique using nanotextured Si (black-Si) that can efficiently trap polymer chains. By increasing the laser intensity, the local concentration of perylene-labelled water-soluble polymer chains increased inside the trapping potential. Accordingly, the excimer fluorescence of perylene increased while the monomer fluorescence decreased, evidenced by a fluorescence colour change from blue to orange. Using nanostructure-assisted optical tweezing, we demonstrate control of the relative intensity ratio of fluorescence of the two fluorophores, thus showing remote and reversible FCC of the polymer assembly.
Randomly Multiplexed Diffractive Lens and Axicon for Spatial and Spectral Imaging
Publisher: MDPI AG
Date: 21-04-2020
DOI: 10.3390/MI11040437
Abstract: A new hybrid diffractive optical element (HDOE) was designed by randomly multiplexing an axicon and a Fresnel zone lens. The HDOE generates two mutually coherent waves, namely a conical wave and a spherical wave, for every on-axis point object in the object space. The resulting self-interference intensity distribution is recorded as the point spread function. A library of point spread functions are recorded in terms of the different locations and wavelengths of the on-axis point objects in the object space. A complicated object illuminated by a spatially incoherent multi-wavelength source generated an intensity pattern that was the sum of the shifted and scaled point spread intensity distributions corresponding to every spatially incoherent point and wavelength in the complicated object. The four-dimensional image of the object was reconstructed using computer processing of the object intensity distribution and the point spread function library.
Selective enhancement of infrared absorption with metal hole arrays
Publisher: The Optical Society
Date: 07-09-2012
DOI: 10.1364/OME.2.001367
Orientation information added to IR hyperspectral imaging: silk and paracetamol
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2551712
Nanotopography as a trigger for the microscale, autogenous and passive lysis of erythrocytes
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C4TB00239C
Abstract: A mechano-responsive topology provides a highly active yet autogenous surface for erythrocyte lysis towards microfluidic haematology platforms.
Surface plasmon resonances in periodic and random patterns of gold nano-disks for broadband light harvesting
Publisher: The Optical Society
Date: 04-05-2012
DOI: 10.1364/OE.20.011466
Silk fibroin as a water-soluble bio-resist and its thermal properties
Publisher: Royal Society of Chemistry (RSC)
Date: 2016
DOI: 10.1039/C5RA20201A
Abstract: E-beam exposure unzips beta-sheets in crystalline domains of silk fibroin and makes it water-soluble, enabling its usage as an aqueous-based electron beam lithography resist.
Two-Dimensional Dy2O3-Pd-PDA/rGO Heterojunction Nanocomposite: Synergistic Effects of Hybridisation, UV Illumination and Relative Humidity on Hydrogen Gas Sensing
Publisher: MDPI AG
Date: 14-02-2022
DOI: 10.3390/CHEMOSENSORS10020078
Abstract: A two-dimensional (2D) Dy2O3-Pd-PDA/rGO heterojunction nanocomposite has been synthesised and tested for hydrogen (H2) gas sensing under various functioning conditions, including different H2 concentrations (50 ppm up to 6000 ppm), relative humidity (up to 25 %RH) and working temperature (up to 200 °C). The material characterisation of Dy2O3-Pd-PDA/rGO nanocomposite performed using various techniques confirms uniform distribution of Pd NPs and 2D Dy2O3 nanostructures on multi-layered porous structure of PDA/rGO nanosheets (NSs) while forming a nanocomposite. Moreover, fundamental hydrogen sensing mechanisms, including the effect of UV illumination and relative humidity (%RH), are investigated. It is observed that the sensing performance is improved as the operating temperature increases from room temperature (RT = 30 °C) to the optimum temperature of 150 °C. The humidity effect investigation revealed a drastic enhancement in sensing parameters as the %RH increased up to 20%. The highest response was found to be 145.2% towards 5000 ppm H2 at 150 °C and 20 %RH under UV illumination (365 nm). This work offers a highly sensitive and selective hydrogen sensor based on a novel 2D nanocomposite using an environmentally friendly and energy-saving synthesis approach, enabling us to detect hydrogen molecules experimentally down to 50 ppm.
Kirchhoff’s Thermal Radiation from Lithography-Free Black Metals
Publisher: MDPI AG
Date: 30-08-2020
DOI: 10.3390/MI11090824
Abstract: Lithography-free black metals composed of a nano-layered stack of materials are attractive not only due to their optical properties but also by virtue of fabrication simplicity and the cost reduction of devices based on such structures. We demonstrate multi-layer black metal layered structures with engineered electromagnetic absorption in the mid-infrared (MIR) wavelength range. Characterization of thin SiO2 and Si films sandwiched between two Au layers by way of experimental electromagnetic radiation absorption and thermal radiation emission measurements as well as finite difference time domain (FDTD) numerical simulations is presented. Comparison of experimental and simulation data derived optical properties of multi-layer black metals provide guidelines for absorber/emitter structure design and potential applications. In addition, relatively simple lithography-free multi-layer structures are shown to exhibit absorber/emitter performance that is on par with what is reported in the literature for considerably more elaborate nano/micro-scale patterned metasurfaces.
Feasibility of Magneto-Encephalography Scan under Color-Tailored Illumination
Publisher: MDPI AG
Date: 25-02-2023
DOI: 10.3390/APP13052988
Abstract: Color plays an important part in human activities, and it also affects circadian cycle and the decision making process. Therefore, it is important to investigate human judgment under different color of illumination, especially because color perception is subjective. In this study, we developed required instrumentation to control the red (R), green (G), blue (B), and amber (A) colored light emitting diode (LED) l for carrying out magneto-encephalography (MEG) brain scans. We developed a software to generate all the colors in the visual spectrum, predefined white light combinations and saturation of an illuminated objects by using RGBA color pallet. The l is required to control from outside of the MEG electromagnetically shielded room with the LED l located inside the MEG room. Hence, USB is used for the communication mode. The feasibility of using LED l with MEG brain scanner has been validated for bio-medical and psychological MEG experiments.
High precision fabrication of antennas and sensors
Publisher: SPIE
Date: 06-03-2015
DOI: 10.1117/12.2180814
Tunable Raman Selectivity via Randomization of a Rectangular Pattern of Nanodisks
Publisher: American Chemical Society (ACS)
Date: 03-10-2014
DOI: 10.1021/PH500228S
Mechano-bactericidal mechanism of graphene nanomaterials
Publisher: The Royal Society
Date: 20-04-2018
Abstract: Growing interest in the bactericidal effect of graphene and graphene-derived nanomaterials has led to the investigation and effective publication of the bactericidal effects of the substratum, many of which present highly conflicting material. The nature of bacterial cell death on graphene bio-interfaces, therefore, remains poorly understood. Here, we review recent findings on the bactericidal effect of graphene and graphene-derived nanomaterials, and proposed mechanisms of cell inactivation, due to mechanical contact with graphene materials, including lipid extraction, physical damage to membranes and pore formation.
Engineering the axial intensity of Bessel beams
Publisher: OSA
Date: 2016
Novel plasmonic applications in physics and chemistry
Publisher: IEEE
Date: 08-2011
Plasmonic nano-structures for opto-mechanical and sensing applications
Publisher: IEEE
Date: 12-2012
Wavelength and refractive index dependence of the geometrical enhancement in surface‐enhanced Raman scattering
Publisher: Wiley
Date: 07-07-2017
DOI: 10.1002/JRS.5190
Antibacterial Action of Nanoparticles by Lethal Stretching of Bacterial Cell Membranes
Publisher: Wiley
Date: 12-11-2020
Nanostructured Antireflective and Thermoisolative Cicada Wings
Publisher: American Chemical Society (ACS)
Date: 29-04-2016
DOI: 10.1021/ACS.LANGMUIR.6B00621
Abstract: Inter-related mechanical, thermal, and optical macroscopic properties of biomaterials are defined at the nanoscale by their constituent structures and patterns, which underpin complex functions of an entire bio-object. Here, the temperature diffusivity of a cicada (Cyclochila australasiae) wing with nanotextured surfaces was measured using two complementary techniques: a direct contact method and IR imaging. The 4-6-μm-thick wing section was shown to have a thermal diffusivity of α⊥ = (0.71 ± 0.15) × 10(-7) m(2)/s, as measured by the contact temperature wave method along the thickness of the wing it corresponds to the inherent thermal property of the cuticle. The in-plane thermal diffusivity value of the wing was determined by IR imaging and was considerably larger at α∥ = (3.6 ± 0.2) × 10(-7) m(2)/s as a result of heat transport via air. Optical properties of wings covered with nanospikes were numerically simulated using an accurate 3D model of the wing pattern and showed that light is concentrated between spikes where intensity is enhanced by up to 3- to 4-fold. The closely packed pattern of nanospikes reduces the reflectivity of the wing throughout the visible light spectrum and over a wide range of incident angles, hence acting as an antireflection coating.
Giant enhancement of THz wave emission under double-pulse excitation of thin water flow
Publisher: MDPI AG
Date: 17-03-2020
DOI: 10.3390/APP10062031
Abstract: Simultaneous measurements of THz wave and hard X-ray emission from thin and flat water flow when irradiated by double femtosecond laser pulses (800 nm, 35 fs/transform-limited, 0.5 kHz, delay times up to 15 ns) were carried out. THz wave measurements by time-domain spectroscopy and X-ray detection by Geiger counters were performed at the transmission and the reflection sides of the flow. THz wave emission spectra show their dynamic peak shifts toward the low frequency with the highest intensity enhancements more than 1.5 × 10 3 times in |E| 2 accumulated over the whole spectrum range of 0–3 THz at the delay time of 4.7 ns between the two pulses. On the other hand, X-ray intensity enhancements are limited to about 20 times at 0 ns under the same experimental conditions. The mechanisms for the spectral changes and the intensity enhancements in THz wave emission are discussed from the viewpoint of laser ablation on the water flow induced by the pre-pulse irradiation.
Ultraviolet-photoelectric effect for augmented contrast and resolution in electron microscopy
Publisher: AIP Publishing
Date: 05-2016
DOI: 10.1063/1.4945357
Abstract: A new tool providing material contrast control in scanning electron microscopy (SEM) is demonstrated. The approach is based on deep-UV illumination during SEM imaging and delivers a novel material based contrast as well as higher resolution due to the photoelectric effect. Electrons liberated from illuminated s le surface contribute to the imaging which can be carried out at a faster acquisition rate, provide material selective contrast, reduce distortions caused by surface charging, and can substitute metal coating in SEM. These features provide high fidelity SEM imaging and are expected to significantly improve the performance of electron beam instruments as well as to open new opportunities for imaging and characterization of materials at the nanoscale.
Laser-Induced Microexplosion Confined in the Bulk of a Sapphire Crystal: Evidence of Multimegabar Pressures
Publisher: American Physical Society (APS)
Date: 25-04-2006
Surface enhanced infrared absorption measurements with micro metal hole array
Publisher: IEEE
Date: 06-2013
Optical properties of periodic/random pattern of Au nanodiscs
Publisher: IEEE
Date: 06-2013
Laser Printing of Plasmonic Nanosponges
Publisher: MDPI AG
Date: 04-12-2020
DOI: 10.3390/NANO10122427
Abstract: Three-dimensional porous nanostructures made of noble metals represent novel class of nanomaterials promising for nonlinear nanooptics and sensors. Such nanostructures are typically fabricated using either reproducible yet time-consuming and costly multi-step lithography protocols or less reproducible chemical synthesis that involve liquid processing with toxic compounds. Here, we combined scalable nanosecond-laser ablation with advanced engineering of the chemical composition of thin substrate-supported Au films to produce nanobumps containing multiple nanopores inside. Most of the nanopores hidden beneath the nanobump surface can be further uncapped using gentle etching of the nanobumps by an Ar-ion beam to form functional 3D plasmonic nanosponges. The nanopores 10–150 nm in diameter were found to appear via laser-induced explosive evaporation/boiling and coalescence of the randomly arranged nucleation sites formed by nitrogen-rich areas of the Au films. Density of the nanopores can be controlled by the amount of the nitrogen in the Au films regulated in the process of their magnetron sputtering assisted with nitrogen-containing discharge gas.
Human Milk Sodium and Potassium as Markers of Mastitis in Mothers of Preterm Infants
Publisher: Mary Ann Liebert Inc
Date: 12-2022
Black-CuO: Surface-enhanced Raman scattering and infrared properties
Publisher: Royal Society of Chemistry (RSC)
Date: 2015
DOI: 10.1039/C5NR04783H
Abstract: Conformally Au coated nano-textured cupric Cu( ii ) oxide surfaces function as high performance substrates for surface enhanced Raman scattering spectroscopy.
Fluorescent color centers in laser ablated 4H-SiC nanoparticles
Publisher: The Optical Society
Date: 23-03-2017
DOI: 10.1364/OL.42.001297
Ultra-Short-Pulse Lasers—Materials—Applications
Publisher: MDPI
Date: 15-10-2021
Light enhancement in surface-enhanced Raman scattering at oblique incidence
Publisher: Springer Science and Business Media LLC
Date: 10-07-2012
Deep-UV fluorescence lifetime imaging microscopy
Publisher: The Optical Society
Date: 28-09-2015
DOI: 10.1364/PRJ.3.000283
Long-range interaction of localized surface plasmons in periodic and random patterns of Au nanoparticles
Publisher: Springer Science and Business Media LLC
Date: 05-11-2013
Surface-enhanced Raman scattering: effective optical constants for electric field modelling of nanostructured Ag films
Publisher: SPIE
Date: 17-09-2016
DOI: 10.1117/12.2236169
SERS scaling rules
Publisher: Springer Science and Business Media LLC
Date: 27-08-2014
Kirchhoff’s metasurfaces towards efficient photo-thermal energy conversion
Publisher: Springer Science and Business Media LLC
Date: 04-06-2019
DOI: 10.1038/S41598-019-44781-4
Abstract: Thermo-optical properties of the nanodisc and metal hole array plasmonic perfect absorber (PPA) metasurfaces were designed and characterized at mid-infrared wavelengths. Both, radiation emitter and detector systems operating in various spectral domains are highly sought after for a erse range of applications, one ex le being future sensor networks employed in the internet-of-things. Reciprocity of the absorbance and emittance is shown experimentally, i.e., the PPAs are demonstrated to follow Kirchhoff’s law where the patterns exhibiting a strong optical absorption were found to be effective thermal emitters. Hence, the Kirchhoff’s law is experimentally validated for the metasurfaces in the IR spectral domain where there is a lack of solutions for spectrally narrow-band emitters. The highest efficiency of radiation-to-heat and heat-to-radiation conversion was obtained for Au-Si-Au composite structures.
First Principles Calculations Toward Understanding SERS of 2,2′‐Bipyridyl Adsorbed on Au, Ag, and Au–Ag Nanoalloy
Publisher: Wiley
Date: 03-10-2018
DOI: 10.1002/JCC.25603
Abstract: First principles electrodyanmics and quantum chemical simulations are performed to gain insights into the underlying mechanisms of the surface enhanced Raman spectra of 22BPY adsorbed on pure Au and Ag as well as on Au-Ag alloy nanodiscs. Experimental SERS spectra from Au and Ag nanodiscs show similar peaks, whereas those from Au-Ag alloy reveal new spectral features. The physical enhancement factors due to surface nano-texture were considered by numerical FDTD simulations of light intensity distribution for the nano-textured Au, Ag, and Au-Ag alloy and compared with experimental results. For the chemical insights of the enhancement, the DFT calculations with the dispersion interaction were performed using Au
Synthesis of super-dense phase of aluminum under extreme pressure and temperature conditions created by femtosecond laser pulses in sapphire
Publisher: SPIE
Date: 09-02-2012
DOI: 10.1117/12.906946
Wrinkled axicons: shaping light from cusps
Publisher: The Optical Society
Date: 07-10-2016
DOI: 10.1364/OE.24.024075
Nanoscale chemical mapping of laser-solubilized silk
Publisher: IOP Publishing
Date: 22-11-2017
Nanotextured CuO: sensing and light harvesting platform
Publisher: SPIE
Date: 13-03-2015
DOI: 10.1117/12.2082601
Magnetic field induced alignment of macroradical epoxy for enhanced electrical properties
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1SM01731D
Abstract: Improving the electrical performance of macroradical epoxy thermosets to surpass the semiconductor threshold requires a comprehensive understanding of the electrical charge transport mechanisms and characteristics.
Author Correction: Orientational Mapping Augmented Sub-Wavelength Hyper-Spectral Imaging of Silk
Publisher: Springer Science and Business Media LLC
Date: 24-01-2018
DOI: 10.1038/S41598-018-19721-3
Abstract: A correction to this article has been published and is linked from the HTML version of this paper. The error has been fixed in the paper.
<title>Three-dimensional recording and structuring of chalcogenide glasses by femtosecond pulses</title>
Publisher: SPIE
Date: 08-10-2004
DOI: 10.1117/12.596322
The Fate of Osteoblast-Like MG-63 Cells on Pre-Infected Bactericidal Nanostructured Titanium Surfaces
Publisher: MDPI AG
Date: 14-05-2019
DOI: 10.3390/MA12101575
Abstract: Biomaterials that have been newly implanted inside the body are the substratum targets for a “race for the surface”, in which bacterial cells compete against eukaryotic cells for the opportunity to colonize the surface. A victory by the former often results in biomaterial-associated infections, which can be a serious threat to patient health and can undermine the function and performance of the implant. Moreover, bacteria can often have a ‘head start’ if implant contamination has taken place either prior to or during the surgery. Current prevention and treatment strategies often rely on systemic antibiotic therapies, which are becoming increasingly ineffective due to a growing prevalence of antibiotic-resistant bacteria. Nanostructured surfaces that kill bacteria by physically rupturing bacterial cells upon contact have recently emerged as a promising solution for the mitigation of bacterial colonization of implants. Furthermore, these nanoscale features have been shown to enhance the adhesion and proliferation of eukaryotic cells, which is a key to, for ex le, the successful osseointegration of load-bearing titanium implants. The bactericidal activity and biocompatibility of such nanostructured surfaces are often, however, examined separately, and it is not clear to what extent bacterial cell-surface interactions would affect the subsequent outcomes of host-cell attachment and osseointegration processes. In this study, we investigated the ability of bactericidal nanostructured titanium surfaces to support the attachment and growth of osteoblast-like MG-63 human osteosarcoma cells, despite them having been pre-infected with pathogenic bacteria. MG-63 is a commonly used osteoblastic model to study bone cell viability, adhesion, and proliferation on the surfaces of load-bearing biomaterials, such as titanium. The nanostructured titanium surfaces used here were observed to kill the pathogenic bacteria, whilst simultaneously enhancing the growth of MG-63 cells in vitro when compared to that occurring on sterile, flat titanium surfaces. These results provide further evidence in support of nanostructured bactericidal surfaces being used as a strategy to help eukaryotic cells win the “race for the surface” against bacterial cells on implant materials.
Reversible photomodification of LiNbO3 and LiTaO3 by femtosecond laser pulses
Publisher: SPIE
Date: 21-12-2008
DOI: 10.1117/12.759232
3D micro-optical elements for generation of tightly focused vortex beams
Publisher: EDP Sciences
Date: 2015
Towards Safer Primers: A Review
Publisher: MDPI AG
Date: 18-10-2019
DOI: 10.3390/TECHNOLOGIES7040075
Abstract: Primers are used to reliably initiate a secondary explosive in a wide range of industrial and defence applications. However, established primer technologies pose both direct and indirect risks to health and safety. This review analyses a new generation of primer materials and ignition control mechanisms that have been developed to address these risks in firearms. Electrically or optically initiated metal, oxide and semiconductor-based devices show promise as alternatives for heavy metal percussive primers. The prospects for wider use of low-cost, safe, reliable and non-toxic primers are discussed in view of these developments.
Macroradical enables electrical conduction in epoxy thermoset
Publisher: Elsevier BV
Date: 09-2021
Drone Polariscopy—Towards Remote Sensing Applications
Publisher: MDPI
Date: 15-10-2021
Ion-beam and plasma etching of a conical-pores photonic crystal for thin-film solar cell
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2033762
Enhanced Reconstruction of Spatially Incoherent Digital Holograms Using Synthetic Point Spread Holograms
Publisher: MDPI
Date: 15-10-2021
Ultrafast laser induced microexplosion: A new strategy to synthesise super-dense nanomaterials
Publisher: IEEE
Date: 06-2009
From Fundamental toward Applied SERS: Shared Principles and Divergent Approaches
Publisher: Wiley
Date: 25-06-2018
Invasive and Non-Invasive Observation of Occluded Fast Transient Events: Computational Tools
Publisher: MDPI AG
Date: 07-2021
Abstract: Industrial processes involving thermal plasma such as cutting, welding, laser machining with ultra-short laser pulses (nonequilibrium conditions), high temperature melting using electrical discharge or ion-beams, etc., generate non-repeatable fast transient events which can reveal valuable information about the processes. In such industrial environments containing high temperature and radiation, it is often difficult to install conventional lens-based imaging windows and components to observe such events. In this study, we compare imaging requirements and performances with invasive and non-invasive modes when a fast transient event is occluded by a metal window consisting of numerous holes punched through it. Simulation studies were carried out for metal windows with different types of patterns, reconstructed for both invasive and non-invasive modes and compared. Sparks were generated by rapid electrical discharge behind a metal window consisting of thousands of punched through-holes and the time sequence was recorded using a high-speed camera. The time sequence was reconstructed with and without the spatio-spectral point spread functions and compared. Commented MATLAB codes are provided for both invasive and non-invasive modes of reconstruction.
THz Filters made by Laser Ablation of Stainless Steel and Kapton
Publisher: MDPI AG
Date: 04-07-2022
DOI: 10.20944/PREPRINTS202207.0043.V1
Abstract: THz band-pass filters were fabricated by laser ablation of micro-foils of stainless steel and Kapton. Their spectral performance was tested in transmission and re- flection at the THz beamline at the Australian Synchrotron (AuSy). A 25 & mu m Kapton film performed as a Fabry-P& eacute rot etalon with a free spectral range of FSR = 119 cm& minus , high finesse Fc & asymp 17, and was tuneable over ~10 & mu m (at ~5 THz band) with & beta = 30& deg tilt. The structure of the THz beam focal region as extracted by the first mirror (slit) shows a complex polarisation-wavelength- position dependence across the beam. This is important for polarisation sensitive measurements (in transmission and reflection) and requires normalisation at each orientation of linear polarisation.
Single-Step Laser Plasmonic Coloration of Metal Films
Publisher: American Chemical Society (ACS)
Date: 27-12-2017
Abstract: Utilization of structural colors produced by nanosized optical antennas is expected to revolutionize the current display technologies based on an inkjet or a pigmentation-based color printing. Meanwhile, the versatile color-mapping strategy combining the fast single-step single-substrate fabrication cycle with low-cost scalable operation is still missing. We propose lithography-free pure optical approach based on a direct local ablative reshaping of the gold film with nanojoule (nJ)-energy femtosecond laser pulses. Plasmon-color printing at a resolution up to 2.5 × 10
Sagnac interference in integrated photonics
Publisher: AIP Publishing
Date: 15-02-2023
DOI: 10.1063/5.0123236
Abstract: As a fundamental optical approach to interferometry, Sagnac interference has been widely used for reflection manipulation, precision measurements, and spectral engineering in optical systems. Compared to other interferometry configurations, it offers attractive advantages by yielding a reduced system complexity without the need for phase control between different pathways, thus offering a high degree of stability against external disturbance and a low wavelength dependence. The advance of integration fabrication techniques has enabled chip-scale Sagnac interferometers with greatly reduced footprint and improved scalability compared to more conventional approaches implemented by spatial light or optical fiber devices. This facilitates a variety of integrated photonic devices with bidirectional light propagation, showing new features and capabilities compared to unidirectional-light-propagation devices, such as Mach–Zehnder interferometers (MZIs) and ring resonators (RRs). This paper reviews functional integrated photonic devices based on Sagnac interference. First, the basic theory of integrated Sagnac interference devices is introduced, together with comparisons to other integrated photonic building blocks, such as MZIs, RRs, photonic crystal cavities, and Bragg gratings. Next, the applications of Sagnac interference in integrated photonics, including reflection mirrors, optical gyroscopes, basic filters, wavelength (de)interleavers, optical analogues of quantum physics, and others, are systematically reviewed. Finally, the open challenges and future perspectives are discussed.
Simple multi-wavelength imaging of birefringence:case study of silk
Publisher: Springer Science and Business Media LLC
Date: 05-12-2018
DOI: 10.1038/S41598-018-36114-8
Abstract: Polarised light imaging microscopy, with the addition of a liquid crystal (LC) phase retarder, was used to determine the birefringence of silk fibres with high (∼1 μ m) spatial resolution. The measurement was carried out with the silk fibres (the optical slow axis) and the slow axis of the LC-retarder set at parallel angles. The direct fit of the transmission data allowed for high fidelity determination of the birefringence Δn ≈ 1.63 × 10 −2 (with ∼2% uncertainty) of the brown silk fibre, ( Antheraea pernyi ) averaged over the wavelength range λ = (425–625) nm. By measuring retardance at four separate wavelengths, it was possible to determine the true value of the birefringence of a thicker s le when an optical path may include a large number of wavelengths. The numerical procedures and required hardware are described for the do-it-yourself assembly of the imaging polariscope at a fractional budget compared to commercial units.
Incoherent Optical Tweezers on Black Titanium
Publisher: American Chemical Society (ACS)
Date: 04-06-2021
Photo-thermoelectric energy converter with black-Si absorber
Publisher: IEEE
Date: 12-2014
Chiral plasmonic nanostructures: experimental and numerical tools
Publisher: SPIE
Date: 05-03-2013
DOI: 10.1117/12.2002281
Silk patterns made by direct femtosecond laser writing
Publisher: AIP Publishing
Date: 09-2016
DOI: 10.1063/1.4962294
Abstract: Silk patterns in a film of amorphous water-soluble fibroin are created by tailored exposure to femtosecond-laser pulses (1030 nm/230 fs) without the use of photo-initiators. This shows that amorphous silk can be used as a negative tone photo-resist. It is also shown that water insoluble crystalline silk films can be precisely ablated from a glass substrate achieving the patterns of crystalline silk gratings on a glass substrate. Bio-compatible/degradable silk can be laser structured to achieve conformational transformations as demonstrated by infrared spectroscopy.
Sculpturing of photonic crystals by ion beam lithography: towards complete photonic bandgap at visible wavelengths
Publisher: The Optical Society
Date: 14-03-2011
DOI: 10.1364/OE.19.005802
3D nano-structures for laser nano-manipulation
Publisher: Beilstein Institut
Date: 17-09-2013
DOI: 10.3762/BJNANO.4.62
Abstract: The resputtering of gold films from nano-holes defined in a sacrificial PMMA mask, which was made by electron beam lithography, was carried out with a dry plasma etching tool in order to form well-like structures with a high aspect ratio (height/width ≈ 3–4) at the rims of the nano-holes. The extraordinary transmission through the patterns of such nano-wells was investigated experimentally and numerically. By doing numerical simulations of 50-nm and 100-nm diameter polystyrene beads in water and air, we show the potential of such patterns for self-induced back-action (SIBA) trapping. The best trapping conditions were found to be a trapping force of 2 pN/W/μm 2 (numerical result) exerted on a 50-nm diameter bead in water. The simulations were based on the analytical Lorentz force model.
Nanoscale precision in ion milling for optical and terahertz antennas
Publisher: SPIE
Date: 13-03-2015
DOI: 10.1117/12.2082344
Noble metal-modified faceted anatase titania photocatalysts: Octahedron versus decahedron
Publisher: Elsevier BV
Date: 12-2018
All femtosecond optical pump and X-ray probe: holey-axicon for free electron lasers
Publisher: IOP Publishing
Date: 18-12-2020
Focal Plane Array Infrared Imaging of Linear Polymeric Patterns
Publisher: MDPI AG
Date: 11-03-2019
DOI: 10.20944/PREPRINTS201903.0127.V1
Abstract: A focal plane array (FPA) detector was used for hyperspectral imaging in the infrared (IR) spectral region using thermal and synchrotron light sources. FPA Fourier-transform IR (FTIR) imaging microspectroscopy will be able to monitor real time changes at specific absorption bands when combined with high brightness synchrotron source. In this study, several types of s les with unique structural motifs were selected and used for assessing the capability of the FPA-FTIR imaging technique. It was shown that the time required for polariscopy at IR wavelengths can be substantially reduced by the FPA-FTIR imaging approach. By using natural and laser fabricated polymers with sub-wavelength features, alignment of absorbing molecular dipoles was revealed as well as higher order patterns (laser fabricated structures). Micro-spectroscopy of absorber orientation reveals alignment patterns even when they are not spatially resolved.
Near-Field IR Orientational Spectroscopy of Silk
Publisher: MDPI AG
Date: 24-09-2019
DOI: 10.3390/APP9193991
Abstract: Orientational dependence of the IR absorbing amide bands of silk is demonstrated from two orthogonal longitudinal and transverse microtome slices with a thickness of only ∼100 nm. Scanning near-field optical microscopy (SNOM) which preferentially probes orientation perpendicular to the s le’s surface was used. Spatial resolution of the silk–epoxy boundary was ∼100 nm resolution, while the spectra were collected by a ∼10 nm tip. Ratio of the absorbance of the amide-II C-N at 1512 cm − 1 and amide-I C=O β -sheets at 1628 cm − 1 showed sensitivity of SNOM to the molecular orientation. SNOM characterisation is complimentary to the far-field absorbance which is sensitive to the in-plane polarisation. Volumes with cross sections smaller than 100 nm can be characterised for molecular orientation. A method of absorbance measurements at four angles of the slice cut orientation, which is equivalent to the four polarisation angles absorbance measurement, is proposed.
The multi-faceted mechano-bactericidal mechanism of nanostructured surfaces
Publisher: Proceedings of the National Academy of Sciences
Date: 26-05-2020
Abstract: The bactericidal action delivered by rigid nanopillar arrays stems from the mechanical rupture of the bacterial cell membrane however, the precise mechanism may be unique to the in idual nanopillar geometries. In this study, we demonstrate that the bactericidal action of highly ordered, high-aspect-ratio nanopillar arrays may be associated with the relative flexibility of the in idual nanopillars and the mechanical energy stored within the nanopillars. We propose that the lateral stretching of the cell membrane and interactions at the cell edge are induced by elastic pillar deformations that occur during bacterial adhesion. The results obtained in this study provide insight into a previously unknown category of mechano-bactericidal mechanism, highlighting another facet to the mechano-bactericidal action of nanostructured surfaces.
Plasmon-induced photoluminescence and Raman enhancement in Pr:CaF2 crystal by embedded silver nanoparticles
Publisher: Elsevier BV
Date: 11-2020
Laser induced memory bits in photorefractive LiNbO3 and LiTaO3
Publisher: Springer Science and Business Media LLC
Date: 28-05-2008
Diffractive optics for axial intensity shaping of Bessel beams
Publisher: IOP Publishing
Date: 17-07-2018
Influence of the dielectric substrate on the effective optical constants of silver plasmonic films
Publisher: The Optical Society
Date: 26-07-2019
DOI: 10.1364/AO.58.006038
Tissue Characterization Using Synchrotron Radiation at 0.7 THz to 10.0 THz with Extended ATR Apparatus Techniques
Publisher: MDPI AG
Date: 31-10-2022
DOI: 10.3390/S22218363
Abstract: The attenuated total reflection (ATR) apparatus, with an added partial reflection artial transmission mode, was used to demonstrate a novel way of characterizing water-based substances at 0.7 to 10.0 THz at the Australian Synchrotron THz-far infrared beamline. The technique utilized a diamond-crystal-equipped ATR to track temperature-dependent changes in reflectance. A “crossover flare” feature in the spectral scan was noted, which appeared to be a characteristic of water and water-dominated compounds. A “quiet zone” feature was also seen, where no temperature-dependent variation in reflectance exists. The variation in these spectral features can be used as a signature for the presence of bound and bulk water. The method can also potentially identify the presence of fats and oils in a biological specimen. The technique requires minimal s le preparation and is non-destructive. The presented method has the promise to provide a novel, real-time, low-preparation, analytical method for investigating biological material, which offers avenues for rapid medical diagnosis and industrial analysis.
Femtosecond laser interaction with photo-refractive crystals: High frequency field and internal field contributions to the refractive index changes
Publisher: IEEE
Date: 06-2009
Dynamic position shifts of X-ray emission from a water film induced by a pair of time-delayed femtosecond laser pulses
Publisher: The Optical Society
Date: 22-09-2017
DOI: 10.1364/OE.25.024109
Microring resonators with circular element inner-wall gratings for enhanced sensing
Publisher: IOP Publishing
Date: 26-05-2020
Silicon surface processing techniques for micro-systems fabrication
Publisher: Elsevier BV
Date: 08-2003
Ultra-wide free spectral range, enhanced sensitivity, and removed mode splitting SOI optical ring resonator with dispersive metal nanodisks
Publisher: The Optical Society
Date: 18-06-2015
DOI: 10.1364/OL.40.002977
Color centers enabled by direct femto-second laser writing in wide bandgap semiconductors
Publisher: MDPI AG
Date: 31-12-2021
DOI: 10.3390/NANO11010072
Abstract: Color centers in silicon carbide are relevant for applications in quantum technologies as they can produce single photon sources or can be used as spin qubits and in quantum sensing applications. Here, we have applied femtosecond laser writing in silicon carbide and gallium nitride to generate vacancy-related color centers, giving rise to photoluminescence from the visible to the infrared. Using a 515 nm wavelength 230 fs pulsed laser, we produce large arrays of silicon vacancy defects in silicon carbide with a high localization within the confocal diffraction limit of 500 nm and with minimal material damage. The number of color centers formed exhibited power-law scaling with the laser fabrication energy indicating that the color centers are created by photoinduced ionization. This work highlights the simplicity and flexibility of laser fabrication of color center arrays in relevant materials for quantum applications.
Fluorescence Colour Control in Perylene‐Labeled Polymer Chains Trapped by Nanotextured Silicon
Publisher: Wiley
Date: 26-01-2022
Abstract: The ability to modulate, tune, and control fluorescence colour has attracted much attention in photonics‐related research fields. Thus far, it has been impossible to achieve fluorescence colour control (FCC) for material with a fixed structure, size, surrounding medium, and concentration. Here, we propose a novel approach to FCC using optical tweezers. We demonstrate an optical trapping technique using nanotextured Si (black‐Si) that can efficiently trap polymer chains. By increasing the laser intensity, the local concentration of perylene‐labelled water‐soluble polymer chains increased inside the trapping potential. Accordingly, the excimer fluorescence of perylene increased while the monomer fluorescence decreased, evidenced by a fluorescence colour change from blue to orange. Using nanostructure‐assisted optical tweezing, we demonstrate control of the relative intensity ratio of fluorescence of the two fluorophores, thus showing remote and reversible FCC of the polymer assembly.
Imaging with diffractive axicons rapidly milled on sapphire by femtosecond laser ablation
Publisher: Springer Science and Business Media LLC
Date: 22-10-2021
Versatile SERS sensing based on black silicon
Publisher: The Optical Society
Date: 04-03-2015
DOI: 10.1364/OE.23.006763
Analysis of defects patterned by femtosecond pulses inside KBr and SiO2 glass
Publisher: Springer Science and Business Media LLC
Date: 25-02-2016
Laser-Patterned Alumina Mask and Mask-Less Dry Etch of Si for Light Trapping with Photonic Crystal Structures
Publisher: MDPI AG
Date: 26-02-2023
DOI: 10.3390/MI14030550
Abstract: Ultra-short 230 fs laser pulses of a 515 nm wavelength were tightly focused onto 700 nm focal spots and utilised in opening ∼0.4–1 μm holes in alumina Al2O3 etch masks with a 20–50 nm thickness. Such dielectric masks simplify the fabrication of photonic crystal (PhC) light-trapping patterns for the above-Lambertian performance of high-efficiency solar cells. The conditions of the laser ablation of transparent etch masks and the effects sub-surface Si modifications were revealed by plasma etching, numerical modelling, and minority carrier lifetime measurements. Mask-less patterning of Si is proposed using fs laser direct writing for dry plasma etching of Si.
Au-Ag-Cu nano-alloys: tailoring of permittivity
Publisher: Springer Science and Business Media LLC
Date: 27-04-2016
DOI: 10.1038/SREP25010
Abstract: Precious metal alloys enables new possibilities to tailor materials for specific optical functions. Here we present a systematic study of the effects of a nanoscale alloying on the permittivity of Au-Ag-Cu metals at 38 different atomic mixing ratios. The permittivity was measured and analyzed numerically by applying the Drude model. X-ray diffraction (XRD) revealed the face centered cubic lattice of the alloys. Both, optical spectra and XRD results point towards an equivalent composition-dependent electron scattering behavior. Correlation between the fundamental structural parameters of alloys and the resulting optical properties is elucidated. Plasmonic properties of the Au-Ag-Cu alloy nanoparticles were investigated by numerical simulations. Guidelines for designing plasmonic response of nano- structures and their patterns are presented from the material science perspective.
Trace vapour detection at room temperature using Raman spectroscopy
Publisher: Royal Society of Chemistry (RSC)
Date: 2014
DOI: 10.1039/C3AN01522J
Abstract: A miniaturized flow-through system consisting of a gold coated silicon substrate based on enhanced Raman spectroscopy has been used to study the detection of vapour from model explosive compounds.
A random coefficient approach to the estimation of residential end-use load profiles
Publisher: Elsevier BV
Date: 12-1991
Laser-matter interaction in the bulk of a transparent solid: Confined microexplosion and void formation
Publisher: American Physical Society (APS)
Date: 06-06-2006
Paracetamol micro-structure analysis by optical mapping
Publisher: Elsevier BV
Date: 04-2019
Biomimetic Nanopillar Silicon Surfaces Rupture Fungal Spores
Publisher: MDPI AG
Date: 09-01-2023
DOI: 10.3390/IJMS24021298
Abstract: The mechano-bactericidal action of nanostructured surfaces is well-documented however, synthetic nanostructured surfaces have not yet been explored for their antifungal properties toward filamentous fungal species. In this study, we developed a biomimetic nanostructured surface inspired by dragonfly wings. A high-aspect-ratio nanopillar topography was created on silicon (nano-Si) surfaces using inductively coupled plasma reactive ion etching (ICP RIE). To mimic the superhydrophobic nature of insect wings, the nano-Si was further functionalised with trichloro(1H,1H,2H,2H-perfluorooctyl)silane (PFTS). The viability of Aspergillus brasiliensis spores, in contact with either hydrophobic or hydrophilic nano-Si surfaces, was determined using a combination of standard microbiological assays, confocal laser scanning microscopy (CLSM), and focused ion beam scanning electron microscopy (FIB-SEM). Results indicated the breakdown of the fungal spore membrane upon contact with the hydrophilic nano-Si surfaces. By contrast, hydrophobised nano-Si surfaces prevented the initial attachment of the fungal conidia. Hydrophilic nano-Si surfaces exhibited both antifungal and fungicidal properties toward attached A. brasisiensis spores via a 4-fold reduction of attached spores and approximately 9-fold reduction of viable conidia from initial solution after 24 h compared to their planar Si counterparts. Thus, we reveal, for the first time, the physical rupturing of attaching fungal spores by biomimetic hydrophilic nanostructured surfaces.
Frontispiz: Fluorescence Colour Control in Perylene‐Labeled Polymer Chains Trapped by Nanotextured Silicon
Publisher: Wiley
Date: 27-02-2022
Hydrogen Evolution on Nano-StructuredCuO/Pd Electrode: Raman Scattering Study
Publisher: MDPI AG
Date: 05-12-2019
DOI: 10.3390/APP9245301
Abstract: In this study, the processes taking place on the surfaces of nanostructured Cu/CuO and Cu/CuO/Pd electrodes at different potential, E, values in the solutions of 0.1 M KOH in H 2 O and D 2 O (heavy water) were probed by surface enhanced Raman spectroscopy (SERS), and the analysis of electrochemical reactions occurring under experimental conditions is presented. The bands of the SERS spectra of the Cu/CuO/Pd electrode observed in the range of E values from +0.3 V to 0 V (standard hydrogen electrode (SHE)) at 1328–1569 cm − 1 are consistent with the existence of species that are adsorbed or weakly bound to the surface with the energy of interaction close to 15–21 kJ mol − 1 . These bands can be attributed to the ad(ab)sorbed (H 3 O + ) ad , (H 2 + ) ab , and (H 2 + ) ad ions as intermediates in reversible hydrogen evolution and oxidation reactions (HER/HOR) taking place on the Cu/CuO/Pd electrode. There was no isotopic effect observed this is consistent with the dipole nature of the electron-ion pair formation of adsorbed (H 3 O + ) ad and (H 2 + ) ad or (D 3 O + ) ad and (D 2 + ) ad . In accordance with the literature data, SERS bands at 125–146 cm − 1 and ∼520–565 cm − 1 were assigned to Cu(I) and Cu(II) oxygen species. These findings corroborate the quantitative stepwise mechanism of water reduction.
Surface-enhanced Raman scattering sensor based on laser nano-textured surfaces
Publisher: IEEE
Date: 12-2012
Au Nanoplasma as Efficient Hard X-ray Emission Source
Publisher: American Chemical Society (ACS)
Date: 28-10-2016
Novel non-plasmonic optical trapping: nano-structured semiconductor assisted (NASSCA) optical tweezers
Publisher: SPIE
Date: 24-04-2018
DOI: 10.1117/12.2319553
“Race for the Surface”: Eukaryotic Cells Can Win
Publisher: American Chemical Society (ACS)
Date: 16-08-2016
Abstract: With an aging population and the consequent increasing use of medical implants, managing the possible infections arising from implant surgery remains a global challenge. Here, we demonstrate for the first time that a precise nanotopology provides an effective intervention in bacterial cocolonization enabling the proliferation of eukaryotic cells on a substratum surface, preinfected by both live Gram-negative, Pseudomonas aeruginosa, and Gram-positive, Staphylococcus aureus, pathogenic bacteria. The topology of the model black silicon (bSi) substratum not only favors the proliferation of eukaryotic cells but is biocompatible, not triggering an inflammatory response in the host. The attachment behavior and development of filopodia when COS-7 fibroblast cells are placed in contact with the bSi surface are demonstrated in the dynamic study, which is based on the use of real-time sequential confocal imaging. Bactericidal nanotopology may enhance the prospect for further development of inherently responsive antibacterial nanomaterials for bionic applications such as prosthetics and implants.
Ion beam lithography with gold and silicon ions
Publisher: Springer Science and Business Media LLC
Date: 14-03-2016
Light-Induced Tuning and Reconfiguration of Nanophotonic Structures
Publisher: Wiley
Date: 29-08-2017
Edge and Contrast Enhancement Using Spatially Incoherent Correlation Holography Techniques
Publisher: MDPI AG
Date: 16-06-2021
Abstract: Image enhancement techniques (such as edge and contrast enhancement) are essential for many imaging applications. In incoherent holography techniques such as Fresnel incoherent correlation holography (FINCH), the light from an object is split into two, each of which is modulated differently from one another by two different quadratic phase functions and coherently interfered to generate the hologram. The hologram can be reconstructed via a numerical backpropagation. The edge enhancement procedure in FINCH requires the modulation of one of the beams by a spiral phase element and, upon reconstruction, edge-enhanced images are obtained. An optical technique for edge enhancement in coded aperture imaging (CAI) techniques that does not involve two-beam interference has not been established yet. In this study, we propose and demonstrate an iterative algorithm that can yield from the experimentally recorded point spread function (PSF), a synthetic PSF that can generate edge-enhanced reconstructions when processed with the object hologram. The edge-enhanced reconstructions are subtracted from the original reconstructions to obtain contrast enhancement. The technique has been demonstrated on FINCH and CAI methods with different spectral conditions.
Tailoring Metal and Insulator Contributions in Plasmonic Perfect Absorber Metasurfaces
Publisher: American Chemical Society (ACS)
Date: 21-06-2018
Interaction of Giant Unilamellar Vesicles with the Surface Nanostructures on Dragonfly Wings
Publisher: American Chemical Society (ACS)
Date: 10-01-2019
DOI: 10.1021/ACS.LANGMUIR.8B03470
Abstract: The waxy epicuticle of dragonfly wings contains a unique nanostructured pattern that exhibits bactericidal properties. In light of emerging concerns of antibiotic resistance, these mechano-bactericidal surfaces represent a particularly novel solution by which bacterial colonization and the formation of biofilms on biomedical devices can be prevented. Pathogenic bacterial biofilms on medical implant surfaces cause a significant number of human deaths every year. The proposed mechanism of bactericidal activity is through mechanical cell rupture however, this is not yet well understood and has not been well characterized. In this study, we used giant unilamellar vesicles (GUVs) as a simplified cell membrane model to investigate the nature of their interaction with the surface of the wings of two dragonfly species, Austrothemis nigrescens and Trithemis annulata, sourced from Victoria, Australia, and the Baix Ebre and Terra Alta regions of Catalonia, Spain. Confocal laser scanning microscopy and cryo-scanning electron microscopy techniques were used to visualize the interactions between the GUVs and the wing surfaces. When exposed to both natural and gold-coated wing surfaces, the GUVs were adsorbed on the surface, exhibiting significant deformation, in the process of membrane rupture. Differences between the tensile rupture limit of GUVs composed of 1,2-dioleoyl- sn-glycero-3-phosphocholine and the isotropic tension generated from the internal osmotic pressure were used to indirectly determine the membrane tensions, generated by the nanostructures present on the wing surfaces. These were estimated as being in excess of 6.8 mN m
Fresnel incoherent correlation holography with single camera shot
Publisher: Opto-Electronic Advances
Date: 2020
Observation of O_2 inside voids formed in GeO_2 glass by tightly-focused fs-laser pulses
Publisher: The Optical Society
Date: 28-09-2011
DOI: 10.1364/OME.1.001150
Exploiting spatio-spectral aberrations for rapid synchrotron infrared imaging
Publisher: International Union of Crystallography (IUCr)
Date: 09-08-2021
DOI: 10.1107/S1600577521007104
Abstract: The Infrared Microspectroscopy Beamline at the Australian Synchrotron is equipped with a Fourier transform infrared (FTIR) spectrometer, which is coupled with an infrared (IR) microscope and a choice of two detectors: a single-point narrow-band mercury cadmium telluride (MCT) detector and a 64 × 64 multi-pixel focal plane array (FPA) imaging detector. A scanning-based point-by-point mapping method is commonly used with a tightly focused synchrotron IR beam at the s le plane, using an MCT detector and a matching 36× IR reflecting objective and condenser (NA = 0.5), which is time consuming. In this study, the beam size at the s le plane was increased using a 15× objective and the spatio-spectral aberrations were investigated. A correlation-based semi-synthetic computational optical approach was applied to assess the possibilities of exploiting the aberrations to perform rapid imaging rather than a mapping approach.
Laser-Induced Translative Hydrodynamic Mass Snapshots: Noninvasive Characterization and Predictive Modeling via Mapping at Nanoscale
Publisher: American Physical Society (APS)
Date: 25-10-2017
Pheochromocytoma (PC12) Cell Response on Mechanobactericidal Titanium Surfaces
Publisher: MDPI AG
Date: 14-04-2018
DOI: 10.3390/MA11040605
UV illumination for electron and ion beam microscopy and nanofabrication
Publisher: SPIE
Date: 09-09-2019
DOI: 10.1117/12.2528681
3D printed polarizing grids for IR-THz synchrotron radiation
Publisher: IOP Publishing
Date: 25-01-2018
Roadmap on Recent Progress in FINCH Technology
Publisher: MDPI AG
Date: 29-09-2021
Abstract: Fresnel incoherent correlation holography (FINCH) was a milestone in incoherent holography. In this roadmap, two pathways, namely the development of FINCH and applications of FINCH explored by many prominent research groups, are discussed. The current state-of-the-art FINCH technology, challenges, and future perspectives of FINCH technology as recognized by a erse group of researchers contributing to different facets of research in FINCH have been presented.
Black-Si as a Photoelectrode
Publisher: MDPI AG
Date: 05-2020
DOI: 10.3390/NANO10050873
Abstract: The fabrication and characterization of photoanodes based on black-Si (b-Si) are presented using a photoelectrochemical cell in NaOH solution. B-Si was fabricated by maskless dry plasma etching and was conformally coated by tens-of-nm of TiO2 using atomic layer deposition (ALD) with a top layer of CoO x cocatalyst deposited by pulsed laser deposition (PLD). Low reflectivity R 5 % of b-Si over the entire visible and near-IR ( λ 2 μ m) spectral range was favorable for the better absorption of light, while an increased surface area facilitated larger current densities. The photoelectrochemical performance of the heterostructured b-Si photoanode is discussed in terms of the n-n junction between b-Si and TiO2.
Distribution states of graphene in polymer nanocomposites: A review
Publisher: Elsevier BV
Date: 12-2021
Sub-micron period lattice structures of magnetic microtraps for ultracold atoms on an atom chip
Publisher: IOP Publishing
Date: 24-02-2015
Frontispiece: Fluorescence Colour Control in Perylene‐Labeled Polymer Chains Trapped by Nanotextured Silicon
Publisher: Wiley
Date: 27-02-2022
Tailoring plasmonic nanoparticles and fractal patterns
Publisher: SPIE
Date: 21-12-2011
DOI: 10.1117/12.903742
THz photomixer with milled nanoelectrodes on LT-GaAs
Publisher: Springer Science and Business Media LLC
Date: 28-08-2014
Improved Classification of Blurred Images with Deep-Learning Networks Using Lucy-Richardson-Rosen Algorithm
Publisher: MDPI AG
Date: 03-04-2023
DOI: 10.3390/PHOTONICS10040396
Abstract: Pattern recognition techniques form the heart of most, if not all, incoherent linear shift-invariant systems. When an object is recorded using a camera, the object information is s led by the point spread function (PSF) of the system, replacing every object point with the PSF in the sensor. The PSF is a sharp Kronecker Delta-like function when the numerical aperture (NA) is large with no aberrations. When the NA is small, and the system has aberrations, the PSF appears blurred. In the case of aberrations, if the PSF is known, then the blurred object image can be deblurred by scanning the PSF over the recorded object intensity pattern and looking for pattern matching conditions through a mathematical process called correlation. Deep learning-based image classification for computer vision applications gained attention in recent years. The classification probability is highly dependent on the quality of images as even a minor blur can significantly alter the image classification results. In this study, a recently developed deblurring method, the Lucy-Richardson-Rosen algorithm (LR2A), was implemented to computationally refocus images recorded in the presence of spatio-spectral aberrations. The performance of LR2A was compared against the parent techniques: Lucy-Richardson algorithm and non-linear reconstruction. LR2A exhibited a superior deblurring capability even in extreme cases of spatio-spectral aberrations. Experimental results of deblurring a picture recorded using high-resolution smartphone cameras are presented. LR2A was implemented to significantly improve the performances of the widely used deep convolutional neural networks for image classification.
Surface‐enhanced Raman scattering sensing on black silicon
Publisher: Wiley
Date: 17-06-2013
RGB‐Color Image Analysis for Determination of Birefringence of Micro‐Films and Columnar Coatings
Publisher: Wiley
Date: 18-12-2022
Abstract: The birefringence analysis of thin m SiO 2 films deposited via evaporation at a glancing angle of to the normal on resist pillar arrays on Si and nanopatterned SiO 2 substrates is carried out by spectral and color (red–green–blue [RGB]) imaging modes. Retardance and birefringence of the films deposited over flat and structured regions can be distinguished with only ≈1% difference between neighboring regions for the visible spectral range using RGB numerical analysis of images. The Michel‐Lévy color map is used for color rendering of birefringence to make quantitative measurements by numerical RGB color filtering. It is shown that by using at 530 nm waveplate inserted at angle to the cross polarizer‐analyzer setup, the range of changes in chromaticity xy ‐coordinates expands approximately twice upon angular rotation of a birefringent s le. This facilitates a better signal‐to‐noise determination of birefringence. The proposed method with ‐plate color shifting can be directly used to determine birefringence from step‐like spectral features in reflection and transmission polariscopy. Direct measurement of birefringence () and retardance of SiO 2 chevron film is carried out using Berek compensator as a benchmark.
Diamond: a gem for micro-optics
Publisher: Elsevier BV
Date: 09-2018
Laser printed nano-gratings: orientation and period peculiarities
Publisher: Springer Science and Business Media LLC
Date: 09-01-2017
DOI: 10.1038/SREP39989
Abstract: Understanding of material behaviour at nanoscale under intense laser excitation is becoming critical for future application of nanotechnologies. Nanograting formation by linearly polarised ultra-short laser pulses has been studied systematically in fused silica for various pulse energies at 3D laser printing/writing conditions, typically used for the industrial fabrication of optical elements. The period of the nanogratings revealed a dependence on the orientation of the scanning direction. A tilt of the nanograting wave vector at a fixed laser polarisation was also observed. The mechanism responsible for this peculiar dependency of several features of the nanogratings on the writing direction is qualitatively explained by considering the heat transport flux in the presence of a linearly polarised electric field, rather than by temporal and spatial chirp of the laser beam. The confirmed vectorial nature of the light-matter interaction opens new control of material processing with nanoscale precision.
Si-Cr Nano-Alloys Fabricated by Direct Femtosecond Laser Writing
Publisher: MDPI AG
Date: 25-02-2023
DOI: 10.3390/MA16051917
Abstract: Ultra-short 230 fs laser pulses of 515 nm wavelength were tightly focused into 700 nm focal spots and utilised in opening ∼400 nm nano-holes in a Cr etch mask that was tens-of-nm thick. The ablation threshold was found to be 2.3 nJ ulse, double that of plain silicon. Nano-holes irradiated with pulse energies below this threshold produced nano-disks, while higher energies produced nano-rings. Both these structures were not removed by either Cr or Si etch solutions. Subtle sub-1 nJ pulse energy control was harnessed to pattern large surface areas with controlled nano-alloying of Si and Cr. This work demonstrates vacuum-free large area patterning of nanolayers by alloying them at distinct locations with sub-diffraction resolution. Such metal masks with nano-hole opening can be used for formation of random patterns of nano-needles with sub-100 nm separation when applied to dry etching of Si.
Laser Structuring for Control of Coupling Between THz Light and Phonon Modes
Publisher: Japan Laser Processing Society
Date: 10-2016
Nano-rescaling of gold films on polystyrene: Thermal management for SERS
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C6NR06904E
Abstract: Nano-textured Au surfaces were prepared on pre-stretched 2D polystyrene (PS) sheets sputtered with different thicknesses of Au. The Au-coated PS was subjected to thermal annealing above the glass transition temperature at ∼150 °C, thus undergoing surface area rescaling via a volume phase transition. The yellow color of the Au changed from the typical mirror-like appearance to a diffusive dark yellow, progressing to dark brown at the smallest feature size, hence, electromagnetic energy was coupled into the substrate. While the surface area footprint is the same after shrinking the PS, the roughness can be modified from the nano- to the micro-scale for different initial thicknesses of sputtered Au. The nanometer-sized features of surface wrinkles on the Au films make them suitable for surface-enhanced Raman scattering (SERS) sensors that can reach ∼10
Engineering 3D Nanoplasmonic Assemblies for High Performance Spectroscopic Sensing
Publisher: American Chemical Society (ACS)
Date: 14-12-2015
Abstract: We demonstrate the fabrication of plasmonic sensors that comprise gold nanopillar arrays exhibiting high surface areas, and narrow gaps, through self-assembly of hiphilic diblock copolymer micelles on silicon substrates. Silicon nanopillars with high integrity over arbitrary large areas are obtained using copolymer micelles as lithographic templates. The gaps between metal features are controlled by varying the thickness of the evaporated gold. The resulting gold metal nanopillar arrays exhibit an engineered surface topography, together with uniform and controlled separations down to sub-10 nm suitable for highly sensitive detection of molecular analytes by Surface Enhanced Raman Spectroscopy (SERS). The significance of the approach is demonstrated through the control exercised at each step, including template preparation and pattern-transfer steps. The approach is a promising means to address trade-offs between resolutions, throughput, and performance in the fabrication of nanoplasmonic assemblies for sensing applications.
MHz-ultrasound generation by chirped femtosecond laser pulses from gold nano-colloidal suspensions
Publisher: The Optical Society
Date: 19-07-2016
DOI: 10.1364/OE.24.017050
All Femtosecond Optical Pump and X-Ray Probe: Holey-Axicon for Free Electron Laser
Publisher: MDPI AG
Date: 26-05-2020
DOI: 10.20944/PREPRINTS202005.0416.V1
Abstract: We put forward a co-axial pump(optical)-probe(X-rays) experimental concept and show performance of the optical component. A Bessel beam generator with a central 100 micrometers-diameter hole (on the optical axis) was fabricated using femtosecond (fs) laser structuring inside a silica plate. This flat-axicon optical element produces a needle-like axial intensity distribution which can be used for the optical pump pulse. The fs-X-ray free electron laser (X-FEL) beam of sub-1 micrometer diameter can be introduced through the central hole along the optical axis onto a target as a probe. Different realisations of optical pump are discussed. Such optical elements facilitate alignment of ultra-short fs-pulses in space and time and can be used in light-matter interaction experiments at extreme energy densities on the surface and in the volume of targets. Full advantage of ultra-short 10 fs X-FEL probe pulses with fs-pump(optical) opens an unexplored temporal dimension of phase transitions and the fastest laser-induced rates of material heating and quenching. A wider field of applications of fs-laser-enabled structuring of materials and design of specific optical elements for astrophotonics is presented.
Anisotropy of 3D Columnar Coatings in Mid-Infrared Spectral Range
Publisher: MDPI AG
Date: 29-11-2021
DOI: 10.3390/NANO11123247
Abstract: Polarisation analysis in the mid-infrared fingerprint region was carried out on thin (∼1 μm) Si and SiO2 films evaporated via glancing angle deposition (GLAD) method at 70∘ to the normal. Synchrotron-based infrared microspectroscopic measurements were carried out on the Infrared Microspectroscopy (IRM) beamline at Australian Synchrotron. Specific absorption bands, particularly Si-O-Si stretching vibration, was found to follow the angular dependence of ∼cos2θ, consistent with the absorption anisotropy. This unexpected anisotropy stems from the enhanced absorption in nano-crevices, which have orientation following the cos2θ angular dependence as revealed by Fourier transforming the image of the surface of 3D columnar films and numerical modeling of light field enhancement by sub-wavelength nano-crevices.
Deep Deconvolution of Object Information Modulated by a Refractive Lens Using Lucy-Richardson-Rosen Algorithm
Publisher: MDPI AG
Date: 31-08-2022
Abstract: A refractive lens is one of the simplest, most cost-effective and easily available imaging elements. Given a spatially incoherent illumination, a refractive lens can faithfully map every object point to an image point in the sensor plane, when the object and image distances satisfy the imaging conditions. However, static imaging is limited to the depth of focus, beyond which the point-to-point mapping can only be obtained by changing either the location of the lens, object or the imaging sensor. In this study, the depth of focus of a refractive lens in static mode has been expanded using a recently developed computational reconstruction method, Lucy-Richardson-Rosen algorithm (LRRA). The imaging process consists of three steps. In the first step, point spread functions (PSFs) were recorded along different depths and stored in the computer as PSF library. In the next step, the object intensity distribution was recorded. The LRRA was then applied to deconvolve the object information from the recorded intensity distributions during the final step. The results of LRRA were compared with two well-known reconstruction methods, namely the Lucy-Richardson algorithm and non-linear reconstruction.
All-dielectric metasurface for wavefront control at terahertz frequencies
Publisher: SPIE
Date: 05-01-2018
DOI: 10.1117/12.2283090
Additional enhancement in surface-enhanced Raman scattering due to excitation geometry
Publisher: SPIE
Date: 31-01-2012
DOI: 10.1117/12.915963
Arrays of Arbitrarily Shaped Nanoparticles: Overlay‐Errorless Direct Ion Write
Publisher: Wiley
Date: 03-05-2013
Spectroscopy of excised skin patches exposed to THz and far-IR radiation
Publisher: Optica Publishing Group
Date: 07-2021
DOI: 10.1364/BOE.424267
Abstract: Applications of far infrared (Far-IR) and terahertz (THz) radiation in areas such as healthcare and security are fast-growing. As a consequence, humans and the environment are becoming more exposed to mm-wave and Far-IR radiation than previously. We examined typical skin-care and sunscreen ingredients and propitiatory products with transmission FTIR, ATR-FTIR and THz-time domain spectroscopy (THz-TDS) methods using fresh and dehydrated toad and fresh human skin s les for their absorption properties in these frequency ranges. The skin hydration compounds glycerol and sorbitol have comparable absorption characteristics to physiological bulk water. Products containing these and similar hydrating compounds have significant Far-IR absorption characteristics. The sunscreen ingredients ZnO (20 micron), TiO 2 (mesh 325), and graphene platelet demonstrate a generally poor Far-IR absorbance, with TiO 2 displaying some frequency-specific absorption in the 3-6 THz and 12 THz regions. The Far-IR absorbance of proprietary sunscreens was, however, shown not to be significant. The absorption properties of melanin, collagen, bound water, and other constituents are significant in dehydrated skin s les but are not of the same order of importance as the hydrating agents examined.
Highly selective trapping of enteropathogenic E. coli on Fabry-Perot sensor mirrors
Publisher: Elsevier BV
Date: 05-2012
DOI: 10.1016/J.BIOS.2012.03.019
Abstract: Untreated recycled water, such as sewage and graywater, will almost always contain a wide range of agents that are likely to present risks to human health, including chemicals and pathogenic microorganisms. The microbial hazards, such as large numbers of enteric pathogens that can cause gastroenteric illness if ingested, are the main cause of concern for human health. The presence of the enteropathogenic Escherichia coli (EPEC) serotype is of particular concern, as this group of bacteria is responsible for causing severe infant and travelers' diarrhea, gastroenteritis and hemolytic uremic syndrome. A biosensing system based on an optical Fabry-Pérot (FP) cavity, capable of directly detecting the presence of EPEC within 5 min, has been developed using a simple micro-thin double-sided adhesive tape and two semi-transparent FP mirror plates. The system utilizes a poly(methyl methacrylate) (PMMA) or glass substrates sputtered by 40-nm-thick gold thin films serving as FP mirrors. Mirrors have been activated using 0.1M mercaptopropionic acid, influencing an immobilization density of the translocated intimin receptor (TIR) of 100 ng/cm(2). The specificity of recognition was confirmed by exposing TIR functionalized surfaces to four taxonomically related and/or distantly related bacterial strains. It was found that the TIR-functionalized surfaces did not show any bacterial capture for these other bacterial strains within a 15 min incubation period.
Bactericidal activity of black silicon
Publisher: Springer Science and Business Media LLC
Date: 26-11-2013
DOI: 10.1038/NCOMMS3838
Optical fibers for miniaturized surface-enhanced Raman-scattering probes
Publisher: The Optical Society
Date: 25-11-2013
DOI: 10.1364/AO.52.008388
Direct Measurement of Temperature Diffusivity of Nanocellulose-Doped Biodegradable Composite Films
Publisher: MDPI AG
Date: 29-07-2020
DOI: 10.3390/MI11080738
Abstract: The thermal properties of novel nanomaterials play a significant role in determining the performance of the material in technological applications. Herein, direct measurement of the temperature diffusivity of nanocellulose-doped starch–polyurethane nanocomposite films was carried out by the micro-contact method. Polymer films containing up to 2 wt%. of nanocellulose were synthesised by a simple chemical process and are biodegradable. Films of a high optical transmittance T≈80% (for a 200 μm thick film), which were up to 44% crystalline, were characterised. Two different modalities of temperature diffusivity based on (1) a resistance change and (2) micro-thermocouple detected voltage modulation caused by the heat wave, were used for the polymer films with cross sections of ∼100 μm thickness. Twice different in-plane α‖ and out-of-plane α⊥ temperature diffusivities were directly determined with high fidelity: α‖=2.12×10−7 m2/s and α⊥=1.13×10−7 m2/s. This work provides an ex le of a direct contact measurement of thermal properties of nanocellulose composite biodegradable polymer films. The thermal diffusivity, which is usually high in strongly interconnected networks and crystals, was investigated for the first time in this polymer nanocomposite.
Structural and Thermal Diffusivity Analysis of an Organoferroelastic Crystal Showing Scissor-Like Two-Directional Deformation Induced by Uniaxial Compression
Publisher: American Chemical Society (ACS)
Date: 12-10-2023
DOI: 10.1021/JACS.3C05545
Mono- and bi-metallic plasmonic photocatalysts for degradation of organic compounds under UV and visible light irradiation
Publisher: Elsevier BV
Date: 07-2014
Efficient humidity-sensitive electrical response of annealed lithium substituted nickel ferrite (Li–NiFe2O4) nanoparticles under ideal, real and corrosive environments
Publisher: Springer Science and Business Media LLC
Date: 04-09-2018
Photoluminescence in hexagonal silicon carbide by direct femtosecond laser writing
Publisher: The Optical Society
Date: 13-12-2018
DOI: 10.1364/OL.43.006077
Super-dense Al formed by ultrafast laser microexplosion
Publisher: IEEE
Date: 05-2011
Micro-thermocouple on nano-membrane: thermometer for nanoscale measurements
Publisher: Springer Science and Business Media LLC
Date: 20-04-2018
DOI: 10.1038/S41598-018-24583-W
Abstract: A thermocouple of Au-Ni with only 2.5- μ m-wide electrodes on a 30-nm-thick Si 3 N 4 membrane was fabricated by a simple low-resolution electron beam lithography and lift off procedure. The thermocouple is shown to be sensitive to heat generated by laser as well as an electron beam. Nano-thin membrane was used to reach a high spatial resolution of energy deposition and to realise a heat source of sub-1 μ m diameter. This was achieved due to a limited generation of secondary electrons, which increase a lateral energy deposition. A low thermal capacitance of the fabricated devices is useful for the real time monitoring of small and fast temperature changes, e.g., due to convection, and can be detected through an optical and mechanical barrier of the nano-thin membrane. Temperature changes up to ~2 × 10 5 K/s can be measured at 10 kHz rate. A simultaneous down-sizing of both, the heat detector and heat source strongly required for creation of thermal microscopy is demonstrated. Peculiarities of Seebeck constant (thermopower) dependence on electron injection into thermocouple are discussed. Modeling of thermal flows on a nano-membrane with presence of a micro-thermocouple was carried out to compare with experimentally measured temporal response.
Polarisation Control in Arrays of Microlenses and Gratings: Performance in Visible–IR Spectral Ranges
Publisher: MDPI AG
Date: 31-03-2023
DOI: 10.3390/MI14040798
Abstract: Microlens arrays (MLAs) which are increasingly popular micro-optical elements in compact integrated optical systems were fabricated using a femtosecond direct laser write (fs-DLW) technique in the low-shrinkage SZ2080TM photoresist. High-fidelity definition of 3D surfaces on IR transparent CaF2 substrates allowed to achieve ∼50% transmittance in the chemical fingerprinting spectral region 2–5 μm wavelengths since MLAs were only ∼10 μm high corresponding to the numerical aperture of 0.3 (the lens height is comparable with the IR wavelength). To combine diffractive and refractive capabilities in miniaturised optical setup, a graphene oxide (GO) grating acting as a linear polariser was also fabricated by fs-DLW by ablation of a 1 μm-thick GO thin film. Such an ultra-thin GO polariser can be integrated with the fabricated MLA to add dispersion control at the focal plane. Pairs of MLAs and GO polarisers were characterised throughout the visible–IR spectral window and numerical modelling was used to simulate their performance. A good match between the experimental results of MLA focusing and simulations was achieved.
Sierpin´ski fractal plasmonic nanoantennas
Publisher: Wiley
Date: 13-04-2011
Abstract: We propose plasmonic Sierpiński gasket, a self‐replicating fractal, with structural elements spanning from ∼100 nm to ∼5 µm made by standard electron beam lithography (EBL), metal deposition, and lift‐off sequence. Such structures demonstrate light field enhancement from visible to far‐IR spectral range and can be scaled up towards THz band. Numerical simulations show that as the fractal order is increased, the optical extinction band broadens from the visible light towards far‐IR, achieving a light field enhancement of more than four orders of magnitude in the nano‐gap proximity. Such antennas are prospective for IR–THz filter, detection, and emission applications. magnified image Fundamental mode simulation of Sierpiński fourth‐order fractal gold nanoantenna with 10 nm nano‐gap, made by EBL and lift‐off. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Dielectric cross-shaped-resonator-based metasurface for vortex beam generation at mid-IR and THz wavelengths
Publisher: Walter de Gruyter GmbH
Date: 07-2019
Abstract: Metasurfaces are engineered thin surfaces comprising two-dimensional (2D) arrays of sub-wavelength-spaced and sub-wavelength-sized resonators. Metasurfaces can locally manipulate the litude, phase, and polarization of light with high spatial resolution. In this paper, we report numerical and experimental results of a vortex-beam-generating metasurface fabricated specifically for infrared (IR) and terahertz (THz) wavelengths. The designed metasurface consists of a 2D array of dielectric cross-shaped resonators with spatially varying length, thereby providing the desired spatially varying phase shift to the incident light. The metasurface was found to be insensitive to the polarization of the incident light. The dimensions of the cross-resonators were calculated using rigorous finite-difference time-domain analysis. The spectral scalability via physical scaling of the meta-resonators is demonstrated using two vortex-generating optical elements operating at 8.8 μm (IR) and 0.78 THz. The vortex beam generated in the mid-IR spectral range was imaged using a Fourier transform IR (FTIR) imaging miscroscope equipped with a focal plane array detector. This design could be used for efficient wavefront shaping and various optical imaging applications in the mid-IR spectral range, where polarization insensitivity is desired.
Lensless Three-Dimensional Quantitative Phase Imaging Using Phase Retrieval Algorithm
Publisher: MDPI AG
Date: 20-09-2020
Abstract: Quantitative phase imaging (QPI) techniques are widely used for the label-free examining of transparent biological s les. QPI techniques can be broadly classified into interference-based and interferenceless methods. The interferometric methods which record the complex litude are usually bulky with many optical components and use coherent illumination. The interferenceless approaches which need only the intensity distribution and works using phase retrieval algorithms have gained attention as they require lesser resources, cost, space and can work with incoherent illumination. With rapid developments in computational optical techniques and deep learning, QPI has reached new levels of applications. In this tutorial, we discuss one of the basic optical configurations of a lensless QPI technique based on the phase-retrieval algorithm. Simulative studies on QPI of thin, thick, and greyscale phase objects with assistive pseudo-codes and computational codes in Octave is provided. Binary phase s les with positive and negative resist profiles were fabricated using lithography, and a single plane and two plane phase objects were constructed. Light diffracted from a point object is modulated by phase s les and the corresponding intensity patterns are recorded. The phase retrieval approach is applied for 2D and 3D phase reconstructions. Commented codes in Octave for image acquisition and automation using a web camera in an open source operating system are provided.
Optical tweezing and binding at high irradiation powers on black-Si
Publisher: Springer Science and Business Media LLC
Date: 26-09-2017
DOI: 10.1038/S41598-017-12470-9
Abstract: Nowadays, optical tweezers have undergone explosive developments in accordance with a great progress of lasers. In the last decade, a breakthrough brought optical tweezers into the nano-world, overcoming the diffraction limit. This is called plasmonic optical tweezers (POT). POT are powerful tools used to manipulate nanomaterials. However, POT has several practical issues that need to be overcome. First, it is rather difficult to fabricate plasmonic nanogap structures regularly and rapidly at low cost. Second, in many cases, POT suffers from thermal effects (Marangoni convection and thermophoresis). Here, we propose an alternative approach using a nano-structured material that can enhance the optical force and be applied to optical tweezers. This material is metal-free black silicon (MFBS), the plasma etched nano-textured Si. We demonstrate that MFBS-based optical tweezers can efficiently manipulate small particles by trapping and binding. The advantages of MFBS-based optical tweezers are: (1) simple fabrication with high uniformity over wafer-sized areas, (2) free from thermal effects detrimental for trapping, (3) switchable trapping between one and two - dimensions, (4) tight trapping because of no detrimental thermal forces. This is the NON-PLASMONIC optical tweezers.
Characterisation of Biological Materials at THz Frequencies by Attenuated Total Reflection: Lard
Publisher: MDPI AG
Date: 04-12-2020
DOI: 10.3390/APP10238692
Abstract: The penetration depth of an evanescent wave in Attenuated Total Reflection (ATR) is dependent on the wavelength of the radiation utilised. At THz frequencies, the penetration depth into biological tissues is in the order of 0.1 to 0.5 mm rendered pig lard was used as a model s le in this study. A method for the direct measurement of the evanescent wave penetration depth is presented which allows for the estimation of the dispersion of the complex refractive index by using the reflection of the evanescent wave from varying s le depths. The method employs frustrated total internal reflection, and has been demonstrated by using the THz/Far-IR beamline at the Australian synchrotron, and modelled using finite difference time domain (FDTD) simulations.
High-spatial-resolution mapping of superhydrophobic cicada wing surface chemistry using infrared microspectroscopy and infrared imaging at two synchrotron beamlines
Publisher: International Union of Crystallography (IUCr)
Date: 22-03-2013
DOI: 10.1107/S0909049513004056
Abstract: The wings of some insects, such as cicadae, have been reported to possess a number of interesting and unusual qualities such as superhydrophobicity, anisotropic wetting and antibacterial properties. Here, the chemical composition of the wings of the Clanger cicada ( Psaltoda claripennis ) were characterized using infrared (IR) microspectroscopy. In addition, the data generated from two separate synchrotron IR facilities, the Australian Synchrotron Infrared Microspectroscopy beamline (AS-IRM) and the Synchrotron Radiation Center (SRC), University of Wisconsin-Madison, IRENI beamline, were analysed and compared. Characteristic peaks in the IR spectra of the wings were assigned primarily to aliphatic hydrocarbon and amide functionalities, which were considered to be an indication of the presence of waxy and proteinaceous components, respectively, in good agreement with the literature. Chemical distribution maps showed that, while the protein component was homogeneously distributed, a significant degree of heterogeneity was observed in the distribution of the waxy component, which may contribute to the self-cleaning and aerodynamic properties of the cicada wing. When comparing the data generated from the two beamlines, it was determined that the SRC IRENI beamline was capable of producing higher-spatial-resolution distribution images in a shorter time than was achievable at the AS-IRM beamline, but that spectral noise levels per pixel were considerably lower on the AS-IRM beamline, resulting in more favourable data where the detection of weak absorbances is required. The data generated by the two complementary synchrotron IR methods on the chemical composition of cicada wings will be immensely useful in understanding their unusual properties with a view to reproducing their characteristics in, for ex le, industry applications.
Hybrid curved nano-structured micro-optical elements
Publisher: The Optical Society
Date: 18-07-2016
DOI: 10.1364/OE.24.016988
Advanced Multi-Functional Integrated Photonic Filters Based on Coupled Sagnac Loop Reflectors
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 03-2021
Tailoring plasmonic field enhancement in spatial and spectral domains
Publisher: IEEE
Date: 08-2012
Fabrication and replication of micro-optical structures for growth of GaN-based light emitting diodes
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2033709
Metamaterial for Hydrogen Sensing
Publisher: American Chemical Society (ACS)
Date: 15-08-2019
DOI: 10.1021/ACSSENSORS.9B00980
Abstract: A hydrogen sensor based on plasmonic metasurfaces is demonstrated to exhibit the industry-required 10 s reaction time and sensitivity. It consists of a layer of either Y or WO
Black-Si as a platform for sensing
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2033707
Roadmap on Digital Holography-Based Quantitative Phase Imaging.
Publisher: MDPI AG
Date: 26-11-2021
Abstract: Quantitative Phase Imaging (QPI) provides unique means for the imaging of biological or technical microstructures, merging beneficial features identified with microscopy, interferometry, holography, and numerical computations. This roadmap article reviews several digital holography-based QPI approaches developed by prominent research groups. It also briefly discusses the present and future perspectives of 2D and 3D QPI research based on digital holographic microscopy, holographic tomography, and their applications.
Outsmarting superbugs: bactericidal activity of nanostructured titanium surfaces against methicillin- and gentamicin-resistant Staphylococcus aureus ATCC 33592
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9TB00102F
Abstract: The colonisation of biomaterial surfaces by pathogenic bacteria is a significant issue of concern, particularly in light of the rapid rise of antibiotic resistance.
Ultrafast laser-induced micro-explosion: material modification tool
Publisher: OSA
Date: 2016
Black silicon as a platform for bacterial detection
Publisher: AIP Publishing
Date: 11-2015
DOI: 10.1063/1.4934966
Abstract: Surface-enhanced Raman scattering (SERS) shows promise for identifying single bacteria, but the short range nature of the effect makes it most sensitive to the cell membrane, which provides limited information for species-level identification. Here, we show that a substrate based on black silicon can be used to impale bacteria on nanoscale SERS-active spikes, thereby producing spectra that convey information about the internal composition of the bacterial capsule. This approach holds great potential for the development of microfluidic devices for the removal and identification of single bacteria in important clinical diagnostics and environmental monitoring applications.
Correlated emission of X-ray and sound from water film irradiated by femtosecond laser pulses
Publisher: Elsevier BV
Date: 06-2019
Photoluminescence from voids created by femtosecond-laser pulses inside cubic-BN
Publisher: The Optical Society
Date: 03-12-2015
DOI: 10.1364/OL.40.005711
Which period ripples will form on the ablated surface: subwavelength or deep-subwavelength?
Publisher: SPIE
Date: 19-02-2018
DOI: 10.1117/12.2300731
Artificial Antibacterial Surfaces that are Simple to Fabricate
Publisher: Springer International Publishing
Date: 2015
Robust Demultiplexing of Distinct Orbital Angular Momentum Infrared Vortex Beams Into Different Spatial Geometry Over a Broad Spectral Range
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2021
Structural changes in femtosecond laser modified regions inside fused silica
Publisher: IOP Publishing
Date: 11-11-2010
Dielectric geometric phase optical elements fabricated by femtosecond direct laser writing in photoresists
Publisher: AIP Publishing
Date: 05-0004
DOI: 10.1063/1.4982602
Abstract: We propose to use a femtosecond direct laser writing technique to realize dielectric optical elements from photo-resist materials for the generation of structured light from purely geometrical phase transformations. This is illustrated by the fabrication and characterization of spin-to-orbital optical angular momentum couplers generating optical vortices of topological charge from 1 to 20. In addition, the technique is scalable and allows obtaining microscopic to macroscopic flat optics. These results thus demonstrate that direct 3D photopolymerization technology qualifies for the realization of spin-controlled geometric phase optical elements.
Photo-structuring of As2S3glass by femtosecond irradiation
Publisher: The Optical Society
Date: 2006
DOI: 10.1364/OE.14.007751
Abstract: The nonlinear absorption coefficient of As(2)S(3) glass has been measured to be 2.0 cm/GW for femtosecond pulses at 800 nm. Femtosecond laser structuring via two photon absorption in bulk As(2)S(3) glass by erasable and permanent photo-darkening is demonstrated using both holographic and direct multi-beam laser writing.
Localized photocatalysis by Au-titania plasmonics
Publisher: IEEE
Date: 06-2011
The idiosyncratic self-cleaning cycle of bacteria on regularly arrayed mechano-bactericidal nanostructures
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NR05923G
Abstract: Bacterial cells are lysed when they attach onto regularly arrayed silicon nanopillars. Following cell lysis, the cell debris detaches from the surface and is released back into the immediate environment which allows for restored bactericidal activity of the substratum.
Randomization of gold nano-brick arrays: a tool for SERS enhancement
Publisher: The Optical Society
Date: 29-05-2013
DOI: 10.1364/OE.21.013502
Nanotextured surfaces for surface enhanced Raman spectroscopy and sensors
Publisher: SPIE
Date: 04-03-2016
DOI: 10.1117/12.2218461
SERS substrate for detection of explosives
Publisher: Royal Society of Chemistry (RSC)
Date: 2012
DOI: 10.1039/C2NR32409A
Abstract: A novel gold coated femtosecond laser nanostructured sapphire surface - an "optical nose" - based on surface-enhanced Raman spectroscopy (SERS) for detecting vapours of explosive substances was investigated. Four different nitroaromatic vapours at room temperature were tested. Sensor responses were unambiguous and showed response in the range of 0.05-15 μM at 25 °C. The laser fabricated substrate nanostructures produced up to an eight-fold increase in Raman signal over that observed on the unstructured portions of the substrate. This work demonstrates a simple sensing system that is compatible with commercial manufacturing practices to detect taggants in explosives which can undertake as part of an integrated security or investigative mission.
Spectral Shaping Based on Coupled Sagnac Loop Reflectors Formed by a Self-Coupled Wire Waveguide
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2202
Is the nano-explosion really microscopic?
Publisher: Elsevier BV
Date: 07-2009
Energy harvesting with black Si/plasmonics composite material
Publisher: IEEE
Date: 08-2016
High Aspect Ratio Nanostructures Kill Bacteria via Storage and Release of Mechanical Energy.
Publisher: American Chemical Society (ACS)
Date: 31-05-2018
Abstract: The threat of a global rise in the number of untreatable infections caused by antibiotic-resistant bacteria calls for the design and fabrication of a new generation of bactericidal materials. Here, we report a concept for the design of antibacterial surfaces, whereby cell death results from the ability of the nanofeatures to deflect when in contact with attaching cells. We show, using three-dimensional transmission electron microscopy, that the exceptionally high aspect ratio (100-3000) of vertically aligned carbon nanotubes (VACNTs) imparts extreme flexibility, which enhances the elastic energy storage in CNTs as they bend in contact with bacteria. Our experimental and theoretical analyses demonstrate that, for high aspect ratio structures, the bending energy stored in the CNTs is a substantial factor for the physical rupturing of both Gram-positive and Gram-negative bacteria. The highest bactericidal rates (99.3% for Pseudomonas aeruginosa and 84.9% for Staphylococcus aureus) were obtained by modifying the length of the VACNTs, allowing us to identify the optimal substratum properties to kill different types of bacteria efficiently. This work highlights that the bactericidal activity of high aspect ratio nanofeatures can outperform both natural bactericidal surfaces and other synthetic nanostructured multifunctional surfaces reported in previous studies. The present systems exhibit the highest bactericidal activity of a CNT-based substratum against a Gram-negative bacterium reported to date, suggesting the possibility of achieving close to 100% bacterial inactivation on VACNT-based substrata.
Alloy plasmonic materials
Publisher: IEEE
Date: 08-2016
Laser fabricated ripple substrates for surface‐enhanced Raman scattering
Publisher: Wiley
Date: 10-09-2012
Evidence of superdense aluminium synthesized by ultrafast microexplosion
Publisher: Springer Science and Business Media LLC
Date: 23-08-2011
DOI: 10.1038/NCOMMS1449
Ultratrace Nitroaromatic Vapor Detection via Surface-Enhanced Fluorescence on Carbazole-Terminated Black Silicon.
Publisher: American Chemical Society (ACS)
Date: 11-10-2019
DOI: 10.1021/ACSSENSORS.9B01063
Abstract: Detection of nitroaromatic compounds (NACs) is an important applied task for environmental monitoring, medical diagnostics, and forensic analysis. However, detection of NAC vapors is challenging owing to their low vapor pressure and relatively weak sensitivity of the existing detection techniques. Here, we propose a novel concept to design fluorescence (FL) detection platforms based on chemical functionalization of nanotextured dielectric surfaces exhibiting resonant light absorption, trapping, and localization effects. We demonstrate highly-efficient NAC vapor sensor with selective FL-quenching response from monolayers of carbazole moieties covalently bonded to a spiky silicon surface, "black" silicon, produced over the centimeter-scale area using simple reactive ion etching. The sensor is shown to provide unprecedented ppt (10
Mechano-bactericidal actions of nanostructured surfaces
Publisher: Springer Science and Business Media LLC
Date: 17-08-2020
Ripple-patterned substrates for light enhancement applications
Publisher: SPIE
Date: 25-06-2010
DOI: 10.1117/12.871049
Modification of refractive index by a single femtosecond pulse confined inside a bulk of a photorefractive crystal
Publisher: American Physical Society (APS)
Date: 23-02-2010
Augmented sensitivity of an IR-absorption gas sensor employing a metal hole array
Publisher: The Optical Society
Date: 13-06-2013
DOI: 10.1364/OME.3.000968
Scaling Rules of SERS Intensity
Publisher: Wiley
Date: 12-02-2014
Three Waveguide Coupled Sagnac Loop Reflectors for Advanced Spectral Engineering
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 06-2021
Alumina-embedded Au nanowires for SERS sensing
Publisher: IEEE
Date: 06-2011
Direct laser printing of tunable IR resonant nanoantenna arrays
Publisher: Elsevier BV
Date: 03-2019
Infrared Polariscopy Imaging of Linear Polymeric Patterns with a Focal Plane Array
Publisher: MDPI AG
Date: 13-05-2019
DOI: 10.3390/NANO9050732
Abstract: Polariscopy is demonstrated using hyperspectral imaging with a focal plane array (FPA) detector in the infrared (IR) spectral region under illumination by thermal and synchrotron light sources. FPA Fourier-transform IR (FTIR) imaging microspectroscopy is useful for monitoring real time changes at specific absorption bands when combined with a high brightness synchrotron source. In this study, several types of s les with unique structural motifs were selected and used for assessing the capability of polariscopy under this FPA-FTIR imaging technique. It was shown that the time required for polariscopy at IR wavelengths can be substantially reduced by the FPA-FTIR imaging approach. By using natural and laser fabricated polymers with sub-wavelength features, alignment of absorbing molecular dipoles and higher order patterns (laser fabricated structures) were revealed. Spectral polariscopy at the absorption peaks can reveal the orientation of sub-wavelength patterns (even when they are not spatially resolved) or the orientation of the absorbing dipoles.
3D printed gratings: IR-THz applications
Publisher: OSA
Date: 2018
Plasmonic photo-thermoelectric energy converter with black-Si absorber
Publisher: Elsevier BV
Date: 12-2015
Lymphoblastoid cell line with B1 cell characteristics established from a chronic lymphocytic leukemia clone by in vitro EBV infection
Publisher: Informa UK Limited
Date: 2012
Optical readout of hydrogen storage in films of Au and Pd
Publisher: The Optical Society
Date: 22-09-2017
DOI: 10.1364/OE.25.024081
MetaOptics: opensource software for designing metasurface optical element GDSII layouts
Publisher: Optica Publishing Group
Date: 24-01-2020
DOI: 10.1364/OE.384057
Abstract: Metasurfaces have recently emerged as a promising technology to realize flat and ultra-thin optical elements that can manipulate light at sub-wavelength scale. The typical design flow of a metasurface involves tedious Finite Difference Time Domain (FDTD) simulations followed by creation of a GDSII layout of the metasurface phase profile, the latter being essential for fabrication purposes. Both these steps can be time-consuming and involve the usage of expensive software. To make the design process more straightforward, we have developed an open-source software called MetaOptics built using Python for designing a generic metasurface optical element. MetaOptics uses the FDTD simulated phase response data of a set of meta-atoms and converts the phase profile of any given optical element into a metasurface GDSII layout. MetaOptics comes with in-built FDTD data for most commonly used wavelengths in the visible and infrared spectrum. It also has an option to upload user-specific dimension versus transmission phase data for any choice of wavelength. In this work we describe the software’s framework and provide details to guide users to design a metasurface layout using MetaOptics.
Characterization of optical polarization converters made by femtosecond laser writing
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2033928
Optical anisotropy of glancing angle deposited thin films on nano-patterned substrates
Publisher: Optica Publishing Group
Date: 03-2022
DOI: 10.1364/OME.451669
Abstract: This study has demonstrated that 3D columnar micro-films/coatings can be deposited over pre-patterned surfaces with sub-micrometer periodic patterns. Four-angle polarisation analysis of thin (0.4 − 1~ μ m) Si and SiO 2 films, evaporated via glancing angle deposition (GLAD) at 70° to the normal, was carried out in reflection mode using synchrotron infrared microspectroscopy at the Australian Synchrotron. The angular dependence of absorbance followed A ( θ ) ∝ cos 2 θ , confirmed for Si substrates patterned by electron beam lithography and plasma etching, which were used to make checkerboard patterns of Λ = 0.4~ μ m period on Si. Retardance control by birefringence of a patterned SiO 2 substrate coated by columnar SiO 2 is promising for UV-visible applications due to the use of the same material to endow polarisation control.
High performance optical filters based on advanced coupled Sagnac loop waveguide reflector structures
Publisher: SPIE
Date: 05-03-2021
DOI: 10.1117/12.2584020
Additional Enhancement of Electric Field in Surface-Enhanced Raman Scattering due to Fresnel Mechanism
Publisher: Springer Science and Business Media LLC
Date: 08-2013
DOI: 10.1038/SREP02335
Enhanced photoacoustics from gold nano-colloidal suspensions under femtosecond laser excitation
Publisher: The Optical Society
Date: 22-06-2016
DOI: 10.1364/OE.24.014781
Orientational Mapping Augmented Sub-Wavelength Hyper-Spectral Imaging of Silk
Publisher: Springer Science and Business Media LLC
Date: 07-08-2017
DOI: 10.1038/S41598-017-07502-3
Abstract: Molecular alignment underpins optical, mechanical, and thermal properties of materials, however, its direct measurement from volumes with micrometer dimensions is not accessible, especially, for structurally complex bio-materials. How the molecular alignment is linked to extraordinary properties of silk and its amorphous-crystalline composition has to be accessed by a direct measurement from a single silk fiber. Here, we show orientation mapping of the internal silk fiber structure via polarisation-dependent IR absorbance at high spatial resolution of 4.2 μ m and 1.9 μ m in a hyper-spectral IR imaging by attenuated total reflection using synchrotron radiation in the spectral fingerprint region around 6 μ m wavelength. Free-standing longitudinal micro-slices of silk fibers, thinner than the fiber cross section, were prepared by microtome for the four polarization method to directly measure the orientational sensitivity of absorbance in the molecular fingerprint spectral window of the amide bands of β -sheet polypeptides of silk. Microtomed lateral slices of silk fibers, which may avoid possible artefacts that affect spectroscopic measurements with fibers of an elliptical cross sections were used in the study. Amorphisation of silk by ultra-short laser single-pulse exposure is demonstrated.
Phase controlled SERS enhancement
Publisher: Springer Science and Business Media LLC
Date: 24-01-2019
DOI: 10.1038/S41598-018-36491-0
Abstract: Surface-enhanced Raman spectroscopy (SERS) has attracted increasing interest for chemical and biochemical sensing. Several studies have shown that SERS intensities are significantly increased when an optical interference substrate composed of a dielectric spacer and a reflector is used as a supporting substrate. However, the origin of this additional enhancement has not been systematically studied. In this paper, high sensitivity SERS substrates composed of self-assembled core-satellite nanostructures and silica-coated silicon interference layers have been developed. Their SERS enhancement is shown to be a function of the thickness of silica spacer on a more reflective silicon substrate. Finite difference time domain modeling is presented to show that the SERS enhancement is due to a spacer contribution via a sign change of the reflection coefficients at the interfaces. The magnitude of the local-field enhancement is defined by the interference of light reflected from the silica-air and silica-silicon interfaces, which constructively added at the hot spots providing a possibility to maximize intensity in the nanogaps between the self-assembled nanoparticles by changing the thickness of silica layer. The core-satellite assemblies on a 135 nm silica-coated silicon substrate exhibit a SERS activity of approximately 13 times higher than the glass substrate.
FDTD modeling to enhance the performance of an organic solar cell embedded with gold nanoparticles
Publisher: The Optical Society
Date: 21-10-2011
DOI: 10.1364/OME.1.001326
Ultra-pure, water-dispersed Au nanoparticles produced by femtosecond laser ablation and fragmentation
Publisher: Informa UK Limited
Date: 07-2013
DOI: 10.2147/IJN.S44163
Far-side geometrical enhancement in surface-enhanced Raman scattering with Ag plasmonic films
Publisher: SPIE
Date: 02-01-2018
DOI: 10.1117/12.2283335
Four-Polarisation Camera for Anisotropy Mapping at Three Orientations: Micro-Grain of Olivine
Publisher: MDPI AG
Date: 18-09-2023
Programmed Death of Injured
Publisher: American Chemical Society (ACS)
Date: 18-01-2022
DOI: 10.1021/ACS.NANOLETT.1C04243
Abstract: Mechano-bactericidal surfaces deliver lethal effects to contacting bacteria. Until now, cell death has been attributed to the mechanical stress imparted to the bacterial cell envelope by the surface nanostructures however, the process of bacterial death encountering nanostructured surfaces has not been fully illuminated. Here, we perform an in-depth investigation of the mechano-bactericidal action of black silicon (bSi) surfaces toward Gram-negative bacteria
Magnetically Cured Macroradical Epoxy as Antimicrobial Coating
Publisher: Wiley
Date: 06-2023
Abstract: The radical‐bearing epoxy monomer could be the ideal embodiment of multifunctionality in epoxy‐based materials. This study demonstrates the potential of macroradical epoxies as surface coating materials. A diepoxide monomer derivatized with a stable nitroxide radical is polymerized with a diamine hardener under the influence of a magnetic field. The magnetically oriented and stable radicals in the polymer backbone render the coatings antimicrobial. The unconventional use of magnets during polymerization proved crucial in correlating the structure‐property relationships with antimicrobial performance inferred from oscillatory rheological technique, polarized macro‐attenuated total reflectance – infrared (macro‐ATR‐IR) spectroscopy and X‐ray photoelectron spectroscopy (XPS). The magnetic thermal curing influenced the surface morphology, resulting in a synergy of the coating's radical nature with microbiostatic performance assessed using the Kirby‐Bauer test and liquid chromatography – mass spectroscopy (LC–MS). Further, the magnetic curing of blends with a traditional epoxy monomer demonstrates that radical alignment is more critical than radical density in imparting biocidal behavior. This study shows how the systematic use of magnets during polymerization could pave for probing more significant insights into the mechanism of antimicrobial action in radical‐bearing polymers.
Generation of high energy density by fs-laser-induced confined microexplosion
Publisher: IOP Publishing
Date: 11-02-2013
GDOESII: Software for design of diffractive optical elements and phase mask conversion to GDSII lithography files
Publisher: Elsevier BV
Date: 2019
Attenuated Total Reflection at THz Wavelengths: Prospective Use of Total Internal Reflection and Polariscopy
Publisher: MDPI AG
Date: 19-08-2021
DOI: 10.3390/APP11167632
Abstract: Capabilities of the attenuated total reflection (ATR) at THz wavelengths for increased sub-surface depth characterisation of (bio-)materials are presented. The penetration depth of a THz evanescent wave in biological s les is dependent on the wavelength and temperature and can reach 0.1–0.5 mm depth, due to the strong refractive index change ∼0.4 of the ice-water transition this is quite significant and important when studying biological s les. Technical challenges are discussed when using ATR for uneven, heterogeneous, high refractive index s les with the possibility of frustrated total internal reflection (a breakdown of the ATR reflection mode into transmission mode). Local field enhancements at the interface are discussed with numerical/analytical ex les. Maxwell’s scaling is used to model the behaviour of absorber–scatterer inside the materials at the interface with the ATR prism for realistic complex refractive indices of bio-materials. The modality of ATR with a polarisation analysis is proposed, and its principle is illustrated, opening an invitation for its experimental validation. The sensitivity of the polarised ATR mode to the refractive index between the s le and ATR prism is numerically modelled and experimentally verified for background (air) spectra. The design principles of polarisation active optical elements and spectral filters are outlined. The results and proposed concepts are based on experimental conditions at the THz beamline of the Australian Synchrotron.
Corrigendum to: Dielectric cross-shaped-resonator-based metasurface for vortex beam generation at mid-IR and THz wavelengths
Publisher: Walter de Gruyter GmbH
Date: 31-10-2019
Si-based infrared optical filters
Publisher: SPIE-Intl Soc Optical Eng
Date: 14-12-2015
Mechanical inactivation of Staphylococcus aureus and Pseudomonas aeruginosa by titanium substrata with hierarchical surface structures
Publisher: Elsevier BV
Date: 03-2019
Tailoring spontaneous infrared emission of HgTe quantum dots with laser-printed plasmonic arrays
Publisher: Springer Science and Business Media LLC
Date: 04-02-2020
DOI: 10.1038/S41377-020-0247-6
Abstract: Chemically synthesized near-infrared to mid-infrared (IR) colloidal quantum dots (QDs) offer a promising platform for the realization of devices including emitters, detectors, security, and sensor systems. However, at longer wavelengths, the quantum yield of such QDs decreases as the radiative emission rate drops following Fermi’s golden rule, while non-radiative recombination channels compete with light emission. Control over the radiative and non-radiative channels of the IR-emitting QDs is crucially important to improve the performance of IR-range devices. Here, we demonstrate strong enhancement of the spontaneous emission rate of near- to mid-IR HgTe QDs coupled to periodically arranged plasmonic nanoantennas, in the form of nanobumps, produced on the surface of glass-supported Au films via ablation-free direct femtosecond laser printing. The enhancement is achieved by simultaneous radiative coupling of the emission that spectrally matches the first-order lattice resonance of the arrays, as well as more efficient photoluminescence excitation provided by coupling of the pump radiation to the local surface plasmon resonances of the isolated nanoantennas. Moreover, coupling of the HgTe QDs to the lattice plasmons reduces the influence of non-radiative decay losses mediated by the formation of polarons formed between QD surface-trapped carriers and the IR absorption bands of dodecanethiol used as a ligand on the QDs, allowing us to improve the shape of the emission spectrum through a reduction in the spectral dip related to this ligand coupling. Considering the ease of the chemical synthesis and processing of the HgTe QDs combined with the scalability of the direct laser fabrication of nanoantennas with tailored plasmonic responses, our results provide an important step towards the design of IR-range devices for various applications.
Surface defect mediated electron hopping between nanoparticles separated by a nano‐gap
Publisher: Wiley
Date: 22-07-2010
Tunable morphological changes of asymmetric titanium nanosheets with bactericidal properties
Publisher: Elsevier BV
Date: 02-2020
DOI: 10.1016/J.JCIS.2019.10.067
Abstract: Titanium and titanium alloys are often the most popular choice of material for the manufacture of medical implants however, they remain susceptible to the risk of device-related infection caused by the presence of pathogenic bacteria. Hydrothermal etching of titanium surfaces, to produce random nanosheet topologies, has shown remarkable ability to inactivate pathogenic bacteria via a physical mechanism. We expect that systematic tuning of the nanosheet morphology by controlling fabrication parameters, such as etching time, will allow for optimisation of the surface pattern for superior antibacterial efficacy. Using time-dependent hydrothermal processing of bulk titanium, we fabricated bactericidal nanosheets with variable nanoedge morphologies according to a function of etching time. A systematic study was performed to compare the bactericidal efficiency of nanostructured titanium surfaces produced at 0.5, 1, 2, 3, 4, 5, 6, 24 and 60 h of hydrothermal etching. Titanium surfaces hydrothermally treated for a period of 6 h were found to achieve maximal antibacterial efficiency of 99 ± 3% against Gram-negative Pseudomonas aeruginosa and 90 ± 9% against Gram-positive Staphylococcus aureus bacteria, two common human pathogens. These surfaces exhibited nanosheets with sharp edges of approximately 10 nm. The nanotopographies presented in this work exhibit the most efficient mechano-bactericidal activity against both Gram-negative and Gram-positive bacteria of any nanostructured titanium topography reported thus far.
Warm dense matter at the bench-top: Fs-laser-induced confined micro-explosion
Publisher: Elsevier BV
Date: 03-2012
Recording and reading of three-dimensional optical memory in glasses
Publisher: Springer Science and Business Media LLC
Date: 08-08-2003
Using Attenuated Total Reflection (ATR) Apparatus to Investigate the Temperature Dependent Dielectric Properties of Water, Ice, and Tissue-Representative Fats
Publisher: MDPI AG
Date: 11-02-2021
DOI: 10.20944/PREPRINTS202102.0271.V1
Abstract: A novel method of investigating the temperature dependent variation of aspects of the complex refractive index n* in s les in the THz range using continuous, non-polarised, synchrotron radiation is presented. The method relies on the use of ATR apparatus, and retains the advantage of minimal s le preparation, which is a feature of ATR techniques. The method demonstrates the viability of rapidly monitoring temperature reflectance whilst continuously heating or cooling s les by using a temperature variable Thermal S le Stage. The method remains useful when the refractive index of the s le precludes attenuated total reflection study. This is demonstrated with the water reflectance experiments. The temperature dependent ATR reflectance of tissue-representative fats (lard and Lurpak& reg butter) was investigated with the novel approach. Both are within the ATR range of the diamond crystal in a & true& ATR mode. Lard showed no clear temperature variation between -15 0C and 24 0C at 0.7 to 1.15 THz or 1.70 to 2.25 THz. Lard can be regarded as having invariable, constant, dielectric properties within mixtures when biological substances are being assessed for temperature dependent dielectric variation within the stated THz ranges. Lurpak& reg butter (water content 14.7%) displayed temperature dependent reflectance features with a steady decline in reflectivity with increasing temperature. This is in line with the temperature-dependent behaviour of liquid water. There is no rapid change in reflectance, even at -20 0C, suggesting that emulsified water retains liquid-water-like THz properties at freezing temperatures.
Extreme energy density confined inside a transparent crystal: Status and perspectives of solid-plasma-solid transformations
Publisher: MDPI AG
Date: 21-07-2018
DOI: 10.3390/NANO8070555
Abstract: It was demonstrated during the past decade that an ultra-short intense laser pulse tightly-focused deep inside a transparent dielectric generates an energy density in excess of several MJ/cm3. Such an energy concentration with extremely high heating and fast quenching rates leads to unusual solid-plasma-solid transformation paths, overcoming kinetic barriers to the formation of previously unknown high-pressure material phases, which are preserved in the surrounding pristine crystal. These results were obtained with a pulse of a Gaussian shape in space and in time. Recently, it has been shown that the Bessel-shaped pulse could transform a much larger amount of material and allegedly create even higher energy density than what was achieved with the Gaussian beam (GB) pulses. Here, we present a succinct review of previous results and discuss the possible routes for achieving higher energy density employing the Bessel beam (BB) pulses and take advantage of their unique properties.
Structure and Optical Anisotropy of Spider Scales and Silk: The Use of Chromaticity and Azimuth Colors to Optically Characterize Complex Biological Structures
Publisher: MDPI AG
Date: 20-06-2023
DOI: 10.3390/NANO13121894
Abstract: Herein, we give an overview of several less explored structural and optical characterization techniques useful for biomaterials. New insights into the structure of natural fibers such as spider silk can be gained with minimal s le preparation. Electromagnetic radiation (EMR) over a broad range of wavelengths (from X-ray to THz) provides information of the structure of the material at correspondingly different length scales (nm-to-mm). When the s le features, such as the alignment of certain fibers, cannot be characterized optically, polarization analysis of the optical images can provide further information on feature alignment. The 3D complexity of biological s les necessitates that there be feature measurements and characterization over a large range of length scales. We discuss the issue of characterizing complex shapes by analysis of the link between the color and structure of spider scales and silk. For ex le, it is shown that the green-blue color of a spider scale is dominated by the chitin slab’s Fabry–Pérot-type reflectivity rather than the surface nanostructure. The use of a chromaticity plot simplifies complex spectra and enables quantification of the apparent colors. All the experimental data presented herein are used to support the discussion on the structure–color link in the characterization of materials.
Size-controlled gold nanoparticles on octahedral anatase particles as efficient plasmonic photocatalyst
Publisher: Elsevier BV
Date: 06-2017
Chemically non-perturbing SERS detection of a catalytic reaction with black silicon
Publisher: Royal Society of Chemistry (RSC)
Date: 2018
DOI: 10.1039/C8NR02123F
Abstract: All-dielectric resonant nanostructures made of high-index dielectrics have recently emerged as a promising surface-enhanced Raman scattering platform which can complement or replace the metal-based counterparts in routine sensing measurements.
Polariscopy with optical near-fields.
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D2NH00187J
Abstract: Polarisation analysis of light-matter interactions established for propagating optical far-fields is now extended into an evanescent field as demonstrated in this study using an attenuated total reflection (ATR) setup and a synchrotron source at THz frequencies. Scalar intensity
Tipping solutions: emerging 3D nano-fabrication/ -imaging technologies
Publisher: Walter de Gruyter GmbH
Date: 17-06-2017
Abstract: The evolution of optical microscopy from an imaging technique into a tool for materials modification and fabrication is now being repeated with other characterization techniques, including scanning electron microscopy (SEM), focused ion beam (FIB) milling/imaging, and atomic force microscopy (AFM). Fabrication and in situ imaging of materials undergoing a three-dimensional (3D) nano-structuring within a 1−100 nm resolution window is required for future manufacturing of devices. This level of precision is critically in enabling the cross-over between different device platforms (e.g. from electronics to micro-/nano-fluidics and/or photonics) within future devices that will be interfacing with biological and molecular systems in a 3D fashion. Prospective trends in electron, ion, and nano-tip based fabrication techniques are presented.
Effective optical constants of anisotropic silver nanoparticle films with plasmonic properties: erratum
Publisher: The Optical Society
Date: 07-03-2017
DOI: 10.1364/OL.42.001092
Tilted black-Si: ∼045 form-birefringence from sub-wavelength needles
Publisher: Optica Publishing Group
Date: 13-05-2020
DOI: 10.1364/OE.392646
Abstract: The self-organised conical needles produced by plasma etching of silicon (Si), known as black silicon (b-Si), create a form-birefringent surface texture when etching of Si orientated at angles of θ i 50 − 70 ° (angle between the Si surface and vertical plasma E-field). The height of the needles in the form-birefringent region following 15 min etching was d ∼ 200 nm and had a 100 μ m width of the optical retardance/birefringence, characterised using polariscopy. The height of the b-Si needles corresponds closely to the skin-depth of Si ∼ λ /4 for the visible spectral range. Reflection-type polariscope with a voltage-controlled liquid-crystal retarder is proposed to directly measure the retardance Δ n × d / λ ≈ 0.15 of the region with tilted b-Si needles. The quantified form birefringence of Δ n = −0.45 over λ = 400 − 700 nm spectral window was obtained. Such high values of Δ n at visible wavelengths can only be observed in the most birefringence calcite or barium borate as well as in liquid crystals. The replication of b-Si into Ni-shim with high fidelity was also demonstrated and can be used for imprinting of the b-Si nanopattern into other materials.
Antifungal versus antibacterial defence of insect wings
Publisher: Elsevier BV
Date: 12-2021
Optical Trapping of Polystyrene Nanoparticles on Black Silicon: Implications for Trapping and Studying Bacteria and Viruses
Publisher: American Chemical Society (ACS)
Date: 14-09-2020
Microparticles of High Entropy Alloys Made by Laser-Induced Forward Transfer
Publisher: MDPI AG
Date: 15-11-2022
DOI: 10.3390/MA15228063
Abstract: The controlled deposition of CoCrFeNiMo0.2 high-entropy alloy (HEA) microparticles was achieved by using laser-induced forward transfer (LIFT). Ultra-short laser pulses of 230 fs of 515 nm wavelength were tightly focused into ∼2.4 μm focal spots on the ∼50-nm thick plasma-sputtered films of CoCrFeNiMo0.2. The morphology of HEA microparticles can be controlled at different fluences. The HEA films were transferred onto glass substrates by magnetron sputtering in a vacuum (10−8 atm) from the thermal spray-coated substrates. The absorption coefficient of CoCrFeNiMo0.2α≈6×105 cm−1 was determined at 600-nm wavelength. The real and imaginary parts of the refractive index (n+iκ) of HEA were determined from reflectance and transmittance by using nanofilms.
Three-dimensional write-read-erase memory bits by femtosecond laser pulses in photorefractive LiNbO3 crystals
Publisher: Elsevier BV
Date: 05-2008
Formation of nano-voids in transparent dielectrics by femtosecond lasers
Publisher: Elsevier BV
Date: 05-2008
THz photomixer with a 40nm-wide nanoelectrode gap on low-temperature grown GaAs
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2033746
Tailoring spectral position and width of field enhancement by focused ion‐beam patterning of plasmonic nanoparticles
Publisher: Wiley
Date: 30-07-2010
Imaging with Diffractive Axicons Rapidly Milled on Sapphire by Femtosecond Laser Ablation
Publisher: MDPI
Date: 13-03-2023
DOI: 10.3390/HMAM2-14147
Pillars of Life: Is There a Relationship between Lifestyle Factors and the Surface Characteristics of Dragonfly Wings?
Publisher: American Chemical Society (ACS)
Date: 05-06-2018
Remote-sensing concept using polariscopy for orientation determination below the spatial resolution limit
Publisher: SPIE
Date: 05-03-2021
DOI: 10.1117/12.2577096
Statistically quantified measurement of an Alzheimer's marker by surface-enhanced Raman scattering
Publisher: Wiley
Date: 13-08-2015
Abstract: Fibrillar forms of the Amyloid-β (Aβ) protein have been implicated in the early stages of Alzheimer's disease (AD), however there are no standardised assays for soluble Aβ oligomer biomarkers that provide the best indication of the disease progression [1,2]. As a step towards a fast and label-free method for testing different AD biomarkers, we have combined laser nano-textured substrates with a SERS mapping technique and validated it using soluble Aβ-40 oligomers [3-5]. The nano-textured SERS substrates provide fast ( min), label-free spectra associated with soluble Aβ-40 oligomers down to a concentration of 10 nM. Statistical analysis of the spectral intensities mapped over the substrate surface shows a quantitative correlation with the oligomer concentration. Schematics of experiments: SERS mapping of Aβ-40 (left figure: measured SERS intensity overlayed with an SEM image of ripples) was carried out on the laser nano-textured (ripple) surface of sapphire and statistical analysis of the SERS intensity was carried out for qualitative (a high SERS intensity at low probability) and quantitative (a moderate SERS intenisty at the highest probability) measures. Quantitative statistical analysis of SERS mapping data can be performed off line for cross correlations with other known SERS signatures.
Plasmonic nano-printing: large-area nanoscale energy deposition for efficient surface texturing
Publisher: Springer Science and Business Media LLC
Date: 27-07-2017
DOI: 10.1038/LSA.2017.112
Nanoscale optical and structural characterisation of silk
Publisher: Beilstein Institut
Date: 23-04-2019
DOI: 10.3762/BJNANO.10.93
Abstract: The nanoscale composition of silk defining its unique properties via a hierarchial structural anisotropy needs to be analysed at the highest spatial resolution of tens of nanometers corresponding to the size of fibrils made of β-sheets, which are the crystalline building blocks of silk. Nanoscale optical and structural properties of silk have been measured from 100 nm thick longitudinal slices of silk fibers with ca. 10 nm resolution, the highest so far. Optical sub-wavelength resolution in hyperspectral mapping of absorbance and molecular orientation were carried out for comparison at IR wavelengths of 2–10 μm using synchrotron radiation. A reliable distinction of transmission changes by only 1–2% as the anisotropy of amide bands was obtained from nanometer-thin slices of silk.
Mechanism of fine ripple formation on surfaces of (semi)transparent materials via a half-wavelength cavity feedback
Publisher: IOP Publishing
Date: 23-12-2010
DOI: 10.1088/0957-4484/22/5/055304
Abstract: The mechanism of the fine ripples, perpendicular to laser polarization, on the surface of (semi)transparent materials with period smaller than the vacuum wavelength, λ, of the incident radiation is proposed and experimentally validated. The sphere-to-plane transformation of nanoplasma bubbles responsible for the in-bulk ripples accounts for the fine ripples on the surface of dielectrics and semiconductors. The mechanism is demonstrated for 4H:SiC and sapphire surfaces using 800 nm/150 fs and 1030 nm/300 fs laser pulses. The ripples are pinned to the smallest possible standing wave cavity inside material of refractive index n. This defines the corresponding period, Λ = (λ/n)/2, of a light standing wave with intensity, E(2), at the maxima of which surface ablation occurs. The mechanism accounts for the fine ripples at the breakdown conditions. Comparison with ripples recorded on different materials and via other mechanisms using femtosecond pulses is presented and application potential is discussed.
Crosslinking Rapidly Cured Epoxy Resin Thermosets: Experimental and Computational Modeling and Simulation Study
Publisher: MDPI AG
Date: 06-03-2023
Abstract: The power of computational modeling and simulation for establishing clear links between materials’ intrinsic properties and their atomic structure has more and more increased the demand for reliable and reproducible protocols. Despite this increased demand, no one approach can provide reliable and reproducible outcomes to predict the properties of novel materials, particularly rapidly cured epoxy-resins with additives. This study introduces the first computational modeling and simulation protocol for crosslinking rapidly cured epoxy resin thermosets based on solvate ionic liquid (SIL). The protocol combines several modeling approaches, including quantum mechanics (QMs) and molecular dynamics (MDs). Furthermore, it insightfully provides a wide range of thermo-mechanical, chemical, and mechano-chemical properties, which agree with experimental data.
Improvement and stabilization of optical hydrogen sensing ability of Au-Pd alloys
Publisher: Optica Publishing Group
Date: 12-08-2020
DOI: 10.1364/OE.398784
Abstract: Formation of metal hydrides is a signature chemical property of hydrogen and it can be leveraged to enact both storage and detection of this technologically important yet extremely volatile gas. Palladium shows particular promise as a hydrogen storage medium as well as a platform for creating rapid and reliable H 2 optical sensor devices. Furthermore, alloying Pd with other noble metals provides a technologically simple yet powerful way of enacting control over the structural and catalytic properties of the resultant material. Similarly, in addition to alloying, different top-down and bottom-up Pd nanostructuring methods have been proposed and investigated specifically for creating optical H 2 sensors. In this work it was determined that the hydrogen sensing ability of a series of Pd-Au alloy films could be improved by way of a hydrogen over exposure (HOE) treatment. Structural investigation showed that the HOE treatment, in addition to irreversibly altering the film morphology, results in a 1 to 2% expansion in the lattice constant of the metal. By combining a cyclic HOE treatment and alloy aging through annealing, the hydrogen detection sensitivity and response rates of Pd-Au films could be stabilized so that their performance would no longer be appreciably affected by repeated hydrogen uptake and release cycles. This work takes a further step towards routine all-optical detection of part-per-million level hydrogen gas concentrations in Pd-Au alloy films and discussion of ways to enhance response rates is provided.
Ultra-Sensitive Photo-Induced Hydrogen Gas Sensor Based on Two-Dimensional CeO2-Pd-PDA/rGO Heterojunction Nanocomposite
Publisher: MDPI AG
Date: 10-05-2022
DOI: 10.3390/NANO12101628
Abstract: A two-dimensional (2D) CeO2-Pd-PDA/rGO heterojunction nanocomposite has been synthesised via an environmentally friendly, energy efficient, and facile wet chemical procedure and examined for hydrogen (H2) gas sensing application for the first time. The H2 gas sensing performance of the developed conductometric sensor has been extensively investigated under different operational conditions, including working temperature up to 200 °C, UV illumination, H2 concentrations from 50–6000 ppm, and relative humidity up to 30% RH. The developed ceria-based nanocomposite sensor was functional at a relatively low working temperature (100 °C), and its sensing properties were improved under UV illumination (365 nm). The sensor’s response towards 6000 ppm H2 was drastically enhanced in a humid environment (15% RH), from 172% to 416%. Under optimised conditions, this highly sensitive and selective H2 sensor enabled the detection of H2 molecules down to 50 ppm experimentally. The sensing enhancement mechanisms of the developed sensor were explained in detail. The available 4f electrons and oxygen vacancies on the ceria surface make it a promising material for H2 sensing applications. Moreover, based on the material characterisation results, highly reactive oxidant species on the sensor surface formed the electron–hole pairs, facilitated oxygen mobility, and enhanced the H2 sensing performance.
White light three-dimensional imaging using a quasi-random lens
Publisher: Optica Publishing Group
Date: 05-05-2021
DOI: 10.1364/OE.426021
Abstract: Coded aperture imaging (CAI) technology is a rapidly evolving indirect imaging method with extraordinary potential. In recent years, CAI based on chaotic optical waves have been shown to exhibit multidimensional, multispectral, and multimodal imaging capabilities with a signal to noise ratio approaching the range of lens based direct imagers. However, most of the earlier studies used only narrow band illumination. In this study, CAI based on chaotic optical waves is investigated for white light illumination. A numerical study was carried out using scalar diffraction formulation and correlation optics and the lateral and axial resolving power for different spectral width were compared. A binary diffractive quasi-random lens was fabricated using electron beam lithography and the lateral and axial point spread holograms are recorded for white light. Three-dimensional imaging was demonstrated using thick objects consisting of two planes. An integrated sequence of signal processing tools such as non-linear filter, low-pass filter, median filter and correlation filter were applied to reconstruct images with an improved signal to noise ratio. A denoising deep learning neural network (DLNN) was trained using synthetic noisy images generated by the convolution of recorded point spread functions with the virtual object functions under a wide range of aberrations and noises. The trained DLNN was found to reduce further the reconstruction noises.
Angle‐multiplexed optical printing of biomimetic hierarchical 3D textures
Publisher: Wiley
Date: 10-01-2017
Anti-reflective surfaces: Cascading nano/microstructuring
Publisher: AIP Publishing
Date: 10-2016
DOI: 10.1063/1.4964851
Abstract: The creation of anti-reflective surfaces is reliant on the engineering of the surface textures and patterns to enable efficient trapping or transmission of light. Here we demonstrate anti-reflective layers composed of hierarchical nano/microscale features that are prepared on Si using a combination of wet and dry etching processes, and which are both scalable and affordable. The performance of the structured surfaces was tested through optical measurements of the reflectance, transmittance, and scattering spectra from the visible to mid-infrared wavelength regions, and the results were verified using numerical simulations to identify the performance of the textured anti-reflective layers. The anti-reflective properties of the layers were shown to be dramatically improved by the composite nanostructured surfaces over a broad spectral range, which thus provides a basis for the design rules that are essential for the progress towards effective anti-reflector fabrication. At normal incidence, the hierarchical surfaces achieve reflectances that are 10–80 times lower than that of conventional single-etch nano-microstructures. Portions of the absorbed, transmitted, scattered, and reflected light in the visible-IR spectrum are presented to illustrate the results.
Coupling of molecular vibration and metasurface modes for efficient mid-infrared emission
Publisher: Royal Society of Chemistry (RSC)
Date: 2022
DOI: 10.1039/D1TC04519A
Abstract: We demonstrate extraordinarily spectrally selective narrowband mid-infrared radiation via coupling of plasmon resonance and molecular vibration. Absorbance and thermal emittance with resonant peak FWHM ≤ 124 nm at λ = 5.73 μm, corresponding to a Q -factor of ∼92.3 were obtained.
Nonlinear Reconstruction of Images from Patterns Generated by Deterministic or Random Optical Masks—Concepts and Review of Research
Publisher: MDPI AG
Date: 20-06-2022
Abstract: Indirect-imaging methods involve at least two steps, namely optical recording and computational reconstruction. The optical-recording process uses an optical modulator that transforms the light from the object into a typical intensity distribution. This distribution is numerically processed to reconstruct the object’s image corresponding to different spatial and spectral dimensions. There have been numerous optical-modulation functions and reconstruction methods developed in the past few years for different applications. In most cases, a compatible pair of the optical-modulation function and reconstruction method gives optimal performance. A new reconstruction method, termed nonlinear reconstruction (NLR), was developed in 2017 to reconstruct the object image in the case of optical-scattering modulators. Over the years, it has been revealed that the NLR can reconstruct an object’s image modulated by an axicons, bifocal lenses and even exotic spiral diffractive elements, which generate deterministic optical fields. Apparently, NLR seems to be a universal reconstruction method for indirect imaging. In this review, the performance of NLR isinvestigated for many deterministic and stochastic optical fields. Simulation and experimental results for different cases are presented and discussed.
Structural Characterization of Femtosecond Laser Modified Regions Inside Sapphire
Publisher: American Scientific Publishers
Date: 04-2011
Abstract: We report on structural characterization of sapphire photomodified by voids of sub-wavelength diameter surrounded by amorphised regions formed after exposure by tightly-focused femtosecond laser pulses of 800 nm wavelength and 150 fs duration at the single and double-pulse irradiation inside crystalline sapphire. Regrowth of a crystalline phase near the edge between the amorphous and crystalline phases was observed by transmission electron microscopy (TEM) in the case of double-pulse-irradiated locations. Regions patterned by single-pulse-induced voids inside sapphire were characterized by synchrotron X-ray diffraction (XRD) technique. The XRD patterns indicate presence of an expanded phase of the host crystal. The origin of structural changes observed in TEM and XRD is discussed and is consistent with fast thermal quenching.
Three-Dimensional Organization of Self-Encapsulating Gluconobacter oxydans Bacterial Cells
Publisher: American Chemical Society (ACS)
Date: 20-11-2017
Applications of Nanotextured Surfaces
Publisher: Elsevier
Date: 2015
Influence of nanoscale topology on bactericidal efficiency of black silicon surfaces
Publisher: IOP Publishing
Date: 23-05-2017
Abstract: The nanostructuring of materials to create bactericidal and antibiofouling surfaces presents an exciting alternative to common methods of preventing bacterial adhesion. The fabrication of synthetic bactericidal surfaces has been inspired by the anti-wetting and anti-biofouling properties of insect wings, and other topologies found in nature. Black silicon is one such synthetic surfaces which has established bactericidal properties. In this study we show that time-dependent plasma etching of silicon wafers using 15, 30, and 45 min etching intervals, is able to produce different surface geometries with linearly increasing heights of approximately 280, 430, and 610 nm, respectively. After incubation on these surfaces with Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa bacterial cells it was established that smaller, more densely packed pillars exhibited the greatest bactericidal activity with 85% and 89% inactivation of bacterial cells, respectively. The decrease in the pillar heights, pillar cap diameter and inter-pillar spacing corresponded to a subsequent decrease in the number of attached cells for both bacterial species.
Antibacterial titanium nano-patterned arrays inspired by dragonfly wings
Publisher: Springer Science and Business Media LLC
Date: 18-11-2015
DOI: 10.1038/SREP16817
Abstract: Titanium and its alloys remain the most popular choice as a medical implant material because of its desirable properties. The successful osseointegration of titanium implants is, however, adversely affected by the presence of bacterial biofilms that can form on the surface and hence methods for preventing the formation of surface biofilms have been the subject of intensive research over the past few years. In this study, we report the response of bacteria and primary human fibroblasts to the antibacterial nanoarrays fabricated on titanium surfaces using a simple hydrothermal etching process. These fabricated titanium surfaces were shown to possess selective bactericidal activity, eliminating almost 50% of Pseudomonas aeruginosa cells and about 20% of the Staphylococcus aureus cells coming into contact with the surface. These nano-patterned surfaces were also shown to enhance the aligned attachment behavior and proliferation of primary human fibroblasts over 10 days of growth. These antibacterial surfaces, which are capable of exhibiting differential responses to bacterial and eukaryotic cells, represent surfaces that have excellent prospects for biomedical applications.
Hyperspectral mapping of anisotropy
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9NH00340A
Abstract: Hyperspectral imaging is now augmented by separation of the birefringence, dichroism and orientation function at the same wavelength and pixel by combining Malus and Beer–Lambert laws.
Silk: Optical Properties over 12.6 Octaves THz-IR-Visible-UV Range
Publisher: MDPI AG
Date: 28-03-2017
DOI: 10.3390/MA10040356
Thermal to electrical energy converter based on black Si
Publisher: SPIE
Date: 17-04-2015
DOI: 10.1117/12.2082403
Mechano-Bactericidal Titanium Surfaces for Bone Tissue Engineering
Publisher: American Chemical Society (ACS)
Date: 15-10-2020
Absorption and scattering in perfect thermal radiation absorber-emitter metasurfaces
Publisher: Optica Publishing Group
Date: 24-01-2022
DOI: 10.1364/OE.447885
Abstract: Detailed spectral analysis of radiation absorption and scattering behaviors of metasurfaces was carried out via finite-difference time-domain (FDTD) photonic simulations. It revealed that, for typical metal-insulator-metal (MIM) nanodisc metasurfaces, absorbance and scattering cross-sections exhibit a ratio of σ abs / σ sca = 1 at the absorption peak spectral position. This relationship was likewise found to limit the attainable photo-thermal conversion efficiency in experimental and application contexts. By increasing the absorption due to optical materials, such as Cr metal nano-films typically used as an adhesion layer, it is possible to control the total absorption efficiency η = σ abs / σ sca and to make it the dominant extinction mechanism. This guided the design of MIM metasurfaces tailored for near-perfect-absorption and emission of thermal radiation. We present the fabrication as well as the numerical and experimental spectral characterisation of such optical surfaces.
Optoplasmonics: hybridization in 3D
Publisher: SPIE
Date: 07-12-2013
DOI: 10.1117/12.2033716
Single Shot Lensless Interferenceless Phase Imaging of Biochemical Samples Using Synchrotron near Infrared Beam
Publisher: MDPI AG
Date: 24-11-2022
DOI: 10.3390/BIOS12121073
Abstract: Phase imaging of biochemical s les has been demonstrated for the first time at the Infrared Microspectroscopy (IRM) beamline of the Australian Synchrotron using the usually discarded near-IR (NIR) region of the synchrotron-IR beam. The synchrotron-IR beam at the Australian Synchrotron IRM beamline has a unique fork shaped intensity distribution as a result of the gold coated extraction mirror shape, which includes a central slit for rejection of the intense X-ray beam. The resulting beam configuration makes any imaging task challenging. For intensity imaging, the fork shaped beam is usually tightly focused to a point on the s le plane followed by a pixel-by-pixel scanning approach to record the image. In this study, a pinhole was aligned with one of the lobes of the fork shaped beam and the Airy diffraction pattern was used to illuminate biochemical s les. The diffracted light from the s les was captured using a NIR sensitive lensless camera. A rapid phase-retrieval algorithm was applied to the recorded intensity distributions to reconstruct the phase information. The preliminary results are promising to develop multimodal imaging capabilities at the IRM beamline of the Australian Synchrotron.
Laser-induced microexplosion confined in a bulk of silica: Formation of nanovoids
Publisher: AIP Publishing
Date: 15-05-2006
DOI: 10.1063/1.2204847
Abstract: We report on the nanovoid formation inside synthetic silica, viosil, by single femtosecond pulses of 30–100nJ energy, 800nm wavelength, and 180fs duration. It is demonstrated that the void is formed as a result of shock and rarefaction waves at pulse power much lower than the threshold of self-focusing. The shock-compressed region around the nanovoid is demonstrated to have higher chemical reactivity. This was used to reveal the extent of the shock-compressed region by wet etching. Application potential of nanostructuring of dielectrics is discussed.
Using Attenuated Total Reflection (ATR) Apparatus to Investigate the Temperature Dependent Dielectric Properties of Water, Ice, and Tissue-Representative Fats
Publisher: MDPI AG
Date: 12-03-2021
DOI: 10.3390/APP11062544
Abstract: A novel method of investigating the temperature dependent variation of aspects of the complex refractive index n* in s les in the THz range using continuous, non-polarised, synchrotron radiation is presented. The method relies on the use of ATR apparatus, and retains the advantage of minimal s le preparation, which is a feature of ATR techniques. The method demonstrates a “proof of concept” of monitoring temperature reflectance whilst continuously heating or cooling s les by using a temperature variable Thermal S le Stage. The method remains useful when the refractive index of the s le precludes attenuated total reflection study. This is demonstrated with the water reflectance experiments. The temperature dependent ATR reflectance of tissue-representative fats (lard and Lurpak® butter) was investigated with the novel approach. Both are within the ATR range of the diamond crystal in a “true” ATR mode. Lard showed no clear temperature variation between −15 °C and 24 °C at 0.7 to 1.15 THz or 1.70 to 2.25 THz. Lard can be regarded as having invariable, constant, dielectric properties within mixtures when biological substances are being assessed for temperature dependent dielectric variation within the stated THz ranges. Lurpak® butter (water content 14.7%) displayed temperature dependent reflected signal intensity features with a steady decline in reflectivity with increasing temperature. This is in line with the temperature-dependent behaviour of liquid water. There is no rapid change in reflected signal intensity even at −20 °C, suggesting that emulsified water retains liquid-water-like THz properties at freezing temperatures.
Femtosecond laser-induced hard X-ray generation in air from a solution flow of Au nano-sphere suspension using an automatic positioning system
Publisher: The Optical Society
Date: 22-08-2016
DOI: 10.1364/OE.24.019994
Single shot multispectral multidimensional imaging using chaotic waves
Publisher: Springer Science and Business Media LLC
Date: 17-08-2020
DOI: 10.1038/S41598-020-70849-7
Abstract: Multispectral imaging technology is a valuable scientific tool for various applications in astronomy, remote sensing, molecular fingerprinting, and fluorescence imaging. In this study, we demonstrate a single camera shot, lensless, interferenceless, motionless, non-scanning, space, spectrum, and time resolved five-dimensional incoherent imaging technique using tailored chaotic waves with quasi-random intensity and phase distributions. Chaotic waves can distinctly encode spatial and spectral information of an object in single self-interference intensity distribution. In this study, a tailored chaotic wave with a nearly pure phase function and lowest correlation noise is generated using a quasi-random array of pinholes. A unique sequence of signal processing techniques is applied to extract all possible spatial and spectral channels with the least entropy. The depth-wavelength reciprocity is exploited to see colour from depth and depth from colour and the physics of beam propagation is exploited to see at one depth by calibrating at another.
Femtosecond laser-induced confined microexplosion: tool for creation high-pressure phases
Publisher: Springer Science and Business Media LLC
Date: 30-12-2015
DOI: 10.1557/ADV.2015.41
Development of an optical fiber SERS microprobe for minimally invasive sensing applications
Publisher: SPIE
Date: 20-02-2018
DOI: 10.1117/12.2289227
Implementation of a Large-Area Diffractive Lens Using Multiple Sub-Aperture Diffractive Lenses and Computational Reconstruction
Publisher: MDPI AG
Date: 21-12-2022
DOI: 10.3390/PHOTONICS10010003
Abstract: Direct imaging systems that create an image of an object directly on the sensor in a single step are prone to many constraints, as a perfect image is required to be recorded within this step. In designing high resolution direct imaging systems with a diffractive lens, the outermost zone width either reaches the lithography limit or the diffraction limit itself, imposing challenges in fabrication. However, if the imaging mode is switched to an indirect one consisting of multiple steps to complete imaging, then different possibilities open. One such method is the widely used indirect imaging method with Golay configuration telescopes. In this study, a Golay-like configuration has been adapted to realize a large-area diffractive lens with three sub-aperture diffractive lenses. The sub-aperture diffractive lenses are not required to collect light and focus them to a single point as in a direct imaging system, but to focus independently on different points within the sensor area. This approach of a Large-Area Diffractive lens with Integrated Sub-Apertures (LADISA) relaxes the fabrication constraints and allows the sub-aperture diffractive elements to have a larger outermost zone width and a smaller area. The diffractive sub-apertures were manufactured using photolithography. The fabricated diffractive element was implemented in indirect imaging mode using non-linear reconstruction and the Lucy–Richardson–Rosen algorithm with synthesized point spread functions. The computational optical experiments revealed improved optical and computational imaging resolutions compared to previous studies.
Fabrication of nanoparticles for generation of force and torque at nanoscale
Publisher: SPIE
Date: 11-09-2013
DOI: 10.1117/12.2024577
Design concept of a hybrid photo-voltaic/thermal conversion cell for mid-infrared light energy harvester
Publisher: The Optical Society
Date: 06-09-2017
DOI: 10.1364/OME.7.003484
Lethal Interactions of Atomically Precise Gold Nanoclusters and Pseudomonas aeruginosa and Staphylococcus aureus Bacterial Cells
Publisher: American Chemical Society (ACS)
Date: 27-06-2022
Abstract: Ultrasmall metal nanoclusters (NCs) are employed in an array of diagnostic and therapeutic applications due to their tunable photoluminescence, high biocompatibility, polyvalent effect, ease of modification, and photothermal stability. However, gold nanoclusters' (AuNCs') intrinsically antimicrobial properties remain poorly explored and are not well understood. Here, we share an insight into the antimicrobial action of atomically precise AuNCs based on their ability to passively translocate across the bacterial membrane. Functionalized by a hydrophilic modified-bidentate sulfobetaine zwitterionic molecule (AuNC-ZwBuEt) or a more hydrophobic monodentate-thiolate, mercaptohexanoic acid (AuNC-MHA) molecule, 2 nm AuNCs were lethal to both Gram-negative
Influence of nanoscale topology on the bactericidal efficiency of black silicon surfaces (vol 28, 245301, 2017)
Publisher: IOP Publishing
Date: 20-10-2017
3D-Tailored Gold Nanoparticles for Light Field Enhancement and Harvesting over Visible-IR Spectral Range
Publisher: American Chemical Society (ACS)
Date: 04-03-2011
DOI: 10.1021/JP109099M
Comment on bactericidal Effects of Natural Nanotopography of Dragonfly Wing on Escherichia coli
Publisher: American Chemical Society (ACS)
Date: 24-08-2017
Enhanced sensitivity and measurement range SOI microring resonator with integrated one-dimensional photonic crystal
Publisher: The Optical Society
Date: 08-03-2017
Recent Advances in Macro ATR-FTIR Microspectroscopic Technique for High Resolution Surface Characterisation at Australian Synchrotron IR Beamline
Publisher: OSA
Date: 2018
Nanofabrication of mechano-bactericidal surfaces
Publisher: Royal Society of Chemistry (RSC)
Date: 2017
DOI: 10.1039/C7NR05881K
Abstract: The search for alternatives to standard methods of preventing bacterial adhesion and biofilm formation on biotic and abiotic surfaces alike has led to the use of biomimetics to reinvent, through nanofabrication methods, surfaces whereby the nanostructured topography is directly responsible for bacterial inactivation through physico-mechanical means.
Plasmonic hydrogen sensor at infrared wavelengths
Publisher: MYU K.K.
Date: 2017
Alloy materials for plasmonic refractive index sensing
Publisher: MYU K.K.
Date: 2017
Engineering and Localization of Quantum Emitters in Large Hexagonal Boron Nitride Layers
Publisher: American Chemical Society (ACS)
Date: 20-10-2016
Abstract: Hexagonal boron nitride is a wide-band-gap van der Waals material that has recently emerged as a promising platform for quantum photonics experiments. In this work, we study the formation and localization of narrowband quantum emitters in large flakes (up to tens of micrometers wide) of hexagonal boron nitride. The emitters can be activated in as-grown hexagonal boron nitride by electron irradiation or high-temperature annealing, and the emitter formation probability can be increased by ion implantation or focused laser irradiation of the as-grown material. Interestingly, we show that the emitters are always localized at the edges of the flakes, unlike most luminescent point defects in three-dimensional materials. Our results constitute an important step on the roadmap of deploying hexagonal boron nitride in nanophotonics applications.
Micro-Particles of High Entropy Alloys Made by Laser Induced Forward Transfer
Publisher: MDPI AG
Date: 26-09-2022
DOI: 10.20944/PREPRINTS202209.0392.V1
Abstract: Controlled deposition of CoCrFeNiMo0.2 high entropy alloy (HEA) micro-particles was achieved using laser induced forward transfer (LIFT). Ultra-short laser pulses, 230 fs of 515 nm wavelength, were tightly focused into & sim 2.4 & mu m focal spots on the & sim nm thick plasma-sputtered films of CoCrFeNiMo0.2. The HTA films were transferred onto glass substrates by magnetron sputtering in vacuum (10& minus atm) from the thermal spray coated substrates. The absorption coefficient of CoCrFeNiMo0.2 & alpha & asymp 6 & times 105 cm& minus was determined at 600 nm wavelength. The real and imaginary parts of refractive index (n + i& kappa ) of HEA were determined from reflectance and transmittance using nano-films.
Roadmap on chaos-inspired imaging technologies (CI2-Tech)
Publisher: Springer Science and Business Media LLC
Date: 14-02-2022
Plasmonic sensor: Towards parts-per-billion level sensitivity
Publisher: MYU K.K.
Date: 2017
Effective optical constants of anisotropic silver nanoparticle films with plasmonic properties
Publisher: The Optical Society
Date: 22-11-2016
DOI: 10.1364/OL.41.005495
Photoacoustic signal enhancements from gold nano-colloidal suspensions excited by a pair of time-delayed femtosecond pulses.
Publisher: The Optical Society
Date: 03-08-2017
DOI: 10.1364/OE.25.019497
Related Organisations
No related organisations have been discovered for Saulius Juodkazis.
Related Funding Activities
Linkage Projects - Grant ID: LP120100161
Start Date: 2012
End Date: 05-2015
Amount: $90,453.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP220100153
Start Date: 2023
End Date: 12-2024
Amount: $308,586.00
Funder: Australian Research Council
View Funded ActivityLinkage Projects - Grant ID: LP190100505
Start Date: 02-2021
End Date: 02-2024
Amount: $590,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP130101205
Start Date: 2013
End Date: 06-2017
Amount: $210,000.00
Funder: Australian Research Council
View Funded ActivityIndustrial Transformation Training Centres - Grant ID: IC140100023
Start Date: 04-2015
End Date: 06-2019
Amount: $1,800,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE160100124
Start Date: 2016
End Date: 12-2016
Amount: $300,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP170100131
Start Date: 09-2017
End Date: 09-2021
Amount: $571,500.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP120102980
Start Date: 2012
End Date: 04-2016
Amount: $560,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE110100121
Start Date: 2011
End Date: 12-2012
Amount: $360,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP0988054
Start Date: 2009
End Date: 12-2011
Amount: $320,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE170100072
Start Date: 04-2017
End Date: 06-2019
Amount: $600,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE140100104
Start Date: 2014
End Date: 12-2014
Amount: $500,000.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP190103284
Start Date: 2019
End Date: 12-2022
Amount: $450,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE140100162
Start Date: 2014
End Date: 2015
Amount: $300,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE220100150
Start Date: 08-2022
End Date: 07-2023
Amount: $320,000.00
Funder: Australian Research Council
View Funded ActivityLinkage Infrastructure, Equipment And Facilities - Grant ID: LE150100001
Start Date: 2015
End Date: 12-2015
Amount: $410,000.00
Funder: Australian Research Council
View Funded ActivityIndustrial Transformation Training Centres - Grant ID: IC180100005
Start Date: 03-2019
End Date: 03-2025
Amount: $4,889,410.00
Funder: Australian Research Council
View Funded Activity