ORCID Profile
0000-0002-2612-6344
Current Organisation
University of South Australia
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Publisher: Springer Singapore
Date: 24-09-2018
Publisher: The Optical Society
Date: 15-06-2016
DOI: 10.1364/OE.24.014053
Publisher: SPIE-Intl Soc Optical Eng
Date: 24-06-2022
Publisher: Optica Publishing Group
Date: 04-06-2020
DOI: 10.1364/OL.391812
Abstract: The inception of photonic crystal fibers (PCFs) allowed for unprecedented tailoring of waveguide properties for specialty sensing probes. Exposed core microstructured fibers (ECFs) represent a natural evolution of the PCF design for practical liquid and gas sensing. Until now, to the best of our knowledge, only single-mode or few-modes ECFs have been explored. In this Letter, we demonstrate a highly multimode ECF with a lateral access that extends throughout the whole length of the fiber. The ECF is operated as a fiber specklegram sensor for assessing properties of fluids and interrogated using a simple and low-cost setup. The probe exhibits a refractive index resolution and sensitivity of at least 4.6 × 10 − 4 refractive index units (RIUs) and − 10.97 R I U − 1 , respectively. A maximum temperature resolution up to 0.017°C with a − 0.20 ∘ C − 1 temperature sensitivity over the 23°C–28°C range and a liquid level sensing resolution up to 0.12 mm with − 0.015 m m − 1 sensitivity over the 0.0–50.0 mm bathed the length range in water.
Publisher: SPIE
Date: 23-04-2017
DOI: 10.1117/12.2265387
Publisher: SPIE
Date: 24-11-2016
DOI: 10.1117/12.2243631
Publisher: Elsevier BV
Date: 12-2015
Publisher: Elsevier BV
Date: 04-2011
Publisher: SPIE
Date: 17-10-2012
DOI: 10.1117/12.970611
Publisher: AIP Publishing
Date: 10-09-2018
DOI: 10.1063/1.5040861
Abstract: The probing of physiological processes in living organisms is a grand challenge that requires bespoke analytical tools. Optical fiber probes offer a minimally invasive approach to report physiological signals from specific locations inside the body. This perspective article discusses a wide range of such fiber probes developed at the Australian Research Council Centre of Excellence for Nanoscale BioPhotonics. Our fiber platforms use a range of sensing modalities, including embedded nanodiamonds for magnetometry, interferometric fiber cavities for refractive index sensing, and tailored metal coatings for surface plasmon resonance sensing. Other fiber probes exploit molecularly sensitive Raman scattering or fluorescence where optical fibers have been combined with chemical and immunosensors. Fiber imaging probes based on interferometry and computational imaging are also discussed as emerging in vivo diagnostic devices. We provide ex les to illustrate how the convergence of multiple scientific disciplines generates opportunities for the fiber probes to address key challenges in real-time in vivo diagnostics. These future fiber probes will enable the asking and answering of scientific questions that were never possible before.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-02-2022
Publisher: Optica Publishing Group
Date: 24-10-2008
DOI: 10.1364/OE.16.018514
Abstract: Glass microstructured optical fibers have been rendered biologically active for the first time via the immobilization of antibodies within the holes in the fiber cross-section. This has been done by introducing coating layers to the internal surfaces of soft glass fibers. The detection of proteins that bind to these antibodies has been demonstrated experimentally within this system via the use of fluorescence labeling. The approach combines the sensitivity resulting from the long interaction lengths of filled fibers with the selectivity provided by the use of antibodies.
Publisher: Optica Publishing Group
Date: 21-04-2010
DOI: 10.1364/OE.18.009474
Publisher: Elsevier BV
Date: 09-2018
Publisher: The Optical Society
Date: 20-11-2012
DOI: 10.1364/BOE.3.003304
Publisher: The Optical Society
Date: 02-10-2012
DOI: 10.1364/OME.2.001538
Publisher: SPIE
Date: 27-02-2019
DOI: 10.1117/12.2507673
Publisher: SPIE
Date: 02-06-2014
DOI: 10.1117/12.2071261
Publisher: IOP Publishing
Date: 12-03-2021
Abstract: An analysis is provided of fiber-optic Fabry–Perot interferometers designed and fabricated using collimating graded-index fiber (GIF) tips as an alternative to typical highly ergent standard single-mode fibers (SMFs). The collimated beam from the GIF tips allows for significantly longer etalons to be fabricated due to the increased collection efficiency when used either in reflection or transmission mode. We extend previous results, showing that GIF tips using coreless fiber segments can allow for up to four-fold increase in fringe visibility (FV) at 1550 nm compared with standard SMF Fabry–Perot etalons of the same length. The collimating GIF tips help lessen the FV vs cavity length trade-off typically observed in fiber-optic Fabry–Perot systems. We also explore the effects on FV improvement when using capillaries to align the fibres. This paper also provides easily accessible design guidelines and considerations for fabricating GIF based devices at 1550 nm.
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2541105
Publisher: Optica Publishing Group
Date: 2022
DOI: 10.1364/CLEOPR.2022.CTUP1C_02
Abstract: Stimulated Brillouin scattering (SBS) induced by narrow-linewidth high power pulses in a multimode fiber (MMF) is suppressed via controlling the input wavefront, presenting a new route to scaling power in high power fiber lifiers.
Publisher: The Optical Society
Date: 18-12-2012
DOI: 10.1364/OE.20.029378
Publisher: The Optical Society
Date: 18-11-2014
DOI: 10.1364/OE.22.029493
Publisher: Elsevier BV
Date: 03-2020
Publisher: The Optical Society
Date: 14-04-2016
DOI: 10.1364/OE.24.008967
Publisher: Routledge
Date: 23-09-2013
Publisher: SPIE
Date: 14-04-2008
DOI: 10.1117/12.785887
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2023
Publisher: The Optical Society
Date: 12-02-2016
DOI: 10.1364/OE.24.003714
Publisher: SPIE
Date: 30-05-2016
DOI: 10.1117/12.2236009
Publisher: Elsevier BV
Date: 06-2017
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2019
Publisher: The Optical Society
Date: 16-10-2014
DOI: 10.1364/BOE.5.003975
Publisher: SPIE
Date: 15-09-2016
DOI: 10.1117/12.2236321
Publisher: IEEE
Date: 05-2011
Publisher: OSA
Date: 2019
Publisher: MDPI AG
Date: 04-03-2011
DOI: 10.3390/S110302961
Publisher: Elsevier BV
Date: 05-2020
Publisher: The Optical Society
Date: 24-10-2017
DOI: 10.1364/OL.42.004395
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 09-2010
Publisher: Royal Society of Chemistry (RSC)
Date: 2023
DOI: 10.1039/D3AN01047C
Abstract: Isothermal lification technology has trigged a surge in research due to its compatibility with small and portable equipment, simplicity, and high efficiency, especially in light of the COVID-19 pandemic where...
Publisher: SPIE
Date: 14-04-2008
DOI: 10.1117/12.785997
Publisher: Optica Publishing Group
Date: 2022
DOI: 10.1364/CLEOPR.2022.CTHA10C_01
Abstract: We numerically and experimentally demonstrate that spreading power into higher order modes of a multimode optical fiber can be used to suppress stimulated Brillouin scattering for a high-power narrow linewidth system. This opens the opportunity for suppressing nonlinear effects in fibers using adaptive mode launching techniques while retaining the ability to produce spatially coherent beams through control of the light phase.
Publisher: Elsevier BV
Date: 2022
Publisher: The Optical Society
Date: 19-06-2019
DOI: 10.1364/OE.27.018601
Publisher: Elsevier BV
Date: 11-2020
Publisher: SPIE
Date: 05-10-2009
DOI: 10.1117/12.834457
Publisher: Elsevier BV
Date: 2022
Publisher: OSA
Date: 2009
Publisher: Optica Publishing Group
Date: 09-07-2021
DOI: 10.1364/OE.431544
Abstract: Whispering gallery modes (WGMs) in micro-resonators are of interest due to their high Q-factors. Ultra-thin fiber tapers are widely deployed to couple light into micro-resonators but achieving stable and practical coupling for out-of-lab use remains challenging. Here, a new WGM coupling scheme using an exposed-core silica fiber (ECF) is proposed, which overcomes the challenge of using fragile fiber tapers. Microspheres are deposited onto the exposed channel for excitation via the evanescent field of the fiber’s guided modes. The outer jacket of the ECF partially encapsulates the microspheres, protecting them from external physical disturbance. By varying the mode launching conditions in this few-mode ECF, in combination with a Fano resonance effect, we demonstrate a high degree of tunability in the reflection spectrum. Furthermore, we show multi-particle WGM excitation, which could be controlled to occur either simultaneously or separately through controlling the ECF mode launching conditions. This work can bring value towards applications such as optical switches and modulators, multiplexed/distributed biosensing, and multi-point lasing, integrated in a single optical fiber device that avoids fiber post-processing.
Publisher: Elsevier BV
Date: 07-2023
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2541295
Publisher: Optica Publishing Group
Date: 2022
DOI: 10.1364/CLEOPR.2022.CWP17B_02
Abstract: We report a specklegram pressure sensor using a pure silica six-hole novel microstructured optical fiber. This simple and low-cost sensor has the potential for pressure measurement at high temperature harsh environment applications.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2022
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-06-2020
Publisher: OSA
Date: 2019
Publisher: Optica Publishing Group
Date: 24-06-2008
DOI: 10.1364/OL.33.001473
Abstract: A general model of excitation and fluorescence recapturing by the forward and backward modes of filled microstructured optical fibers (MOFs) is presented. We also present experimental results for both backward and forward fluorescence recapturing within a MOF as a function of fiber length and demonstrate a good qualitative agreement between the numerical model and experimental results. We demonstrate higher efficiency of fluorescence recapturing into backward modes in comparison with that of forward modes.
Publisher: The Optical Society
Date: 27-04-2017
DOI: 10.1364/OL.42.001812
Publisher: Optica Publishing Group
Date: 15-03-2022
DOI: 10.1364/OE.443932
Abstract: Fiber specklegram sensors (FSSs) traditionally use statistical methods to analyze specklegrams obtained from fibers for sensing purposes, but can suffer from limitations such as vulnerability to noise and lack of dynamic range. In this paper we demonstrate that deep learning improves the analysis of specklegrams for sensing, which we show here for both air temperature and water immersion length measurements. Two deep neural networks (DNNs) a convolutional neural network and a multi-layer perceptron network, are used and compared to a traditional correlation technique on data obtained from a multimode fiber exposed-core fiber. The ability for the DNNs to be trained against a random noise source such as specklegram translations is also demonstrated.
Publisher: AIP Publishing
Date: 02-2021
DOI: 10.1063/5.0036300
Abstract: The tracking of small particles is an important but challenging task for biological applications such as disease diagnostics and medical research. Current methods are limited to the use of bulky instruments such as flow cytometers and microscopes. Here, a novel technique for the detection and measurement of micron-scale optical scatterers using a few-mode exposed-core microstructured optical fiber is proposed. Through selective mode launching combined with optical frequency domain reflectometry, scatterers located on the fiber core surface can be simultaneously mapped with both longitudinal and transverse information. This technique is demonstrated by detecting the two-dimensional positions of several femtosecond-laser-inscribed micron-scale ablations written at different locations on the fiber core surface. Due to the compact nature of the optical fiber and its local sensitivity to scatterers that are in close proximity to it, this technique has the potential for the measurement and detection of micron-scale particles in difficult to reach biological environments for in vivo applications.
Publisher: Elsevier BV
Date: 11-2023
Publisher: Optica Publishing Group
Date: 09-02-2009
DOI: 10.1364/OE.17.002646
Abstract: We report a new approach for the fabrication of nanowires: the direct drawing of optical fibers with air suspended nanoscale cores. The fibers were made from lead silicate glass using the extrusion technique for preform and jacket tube fabrication. Fibers with core diameters in the range of 420-720 nm and practical outer diameters of 110-200 microm were produced, the smallest core sizes produced to date within optical fibers without tapering. We explored the impact of the core size on the effective mode area and propagation loss of these suspended nanowires relative to circular nanowires reported to date. As for circular nanowires, the propagation loss of these suspended nanowires is dominated by surface roughness induced scattering.
Publisher: SPIE
Date: 29-04-2016
DOI: 10.1117/12.2227354
Publisher: SPIE
Date: 29-04-2016
DOI: 10.1117/12.2227113
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2541320
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-04-2019
Publisher: SPIE
Date: 05-10-2009
DOI: 10.1117/12.835350
Publisher: IEEE
Date: 07-2012
Publisher: SPIE
Date: 02-06-2014
DOI: 10.1117/12.2059161
Publisher: American Chemical Society (ACS)
Date: 06-04-2011
DOI: 10.1021/LA2002496
Abstract: The first microstructured optical fiber-based sensor platform for aluminum ions using a surface-attached derivative of lumogallion (3), a known fluorescence-based indicator, has been fabricated. These fibers allow for strong evanescent field interactions with the surrounding media because of the small core size while also providing the potential for real-time and distributed measurements. The fluorescence response to aluminum ions was first demonstrated by applying the procedure to glass slides. This was achieved through the covalent attachment of the fluorophore to a polyelectrolyte-coated glass surface and then to the internal holes of a suspended-core microstructured optical fiber to give an effective aluminum sensor. Whereas the sensor platform reported is fabricated for aluminum, the approach is versatile, with applicability to the detection of other ions.
Publisher: Wiley
Date: 21-07-2015
DOI: 10.1111/IJAG.12128
Publisher: The Optical Society
Date: 07-01-2016
DOI: 10.1364/OE.24.000378
Publisher: Elsevier BV
Date: 12-2010
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2020
Publisher: Optica Publishing Group
Date: 04-06-2008
DOI: 10.1364/OE.16.009034
Abstract: The absorption and fluorescence sensing properties of liquid-immersed exposed-core microstructured optical fibers are explored for the regime where these structures act as supported nanowires with direct access to the sensing environment. For absorption-based sensing we demonstrate that the amount of power propagating in the sensing region of the exposed-core fiber can compete with that of traditional MOFs. For fluorescence-based sensing, we see that in addition to the enhanced fluorescence capture efficiency already predicted for small-core, high refractive index contrast fibers, an improvement of up to 29% can be gained by using liquid-immersed exposed-core fibers. Additionally, calculation of the losses associated with interfaces between filled and unfilled sections predict significant benefit in using high refractive index substrate glasses for liquid-immersed exposed-core fiber sensing. This work demonstrates that, for fiber dimensions of interest, the exposed-core fiber is an attractive new sensor technology.
Publisher: Optica Publishing Group
Date: 22-07-2020
DOI: 10.1364/OE.397537
Abstract: Femtosecond laser inscribed fiber Bragg gratings in pure-silica suspended-core optical fibers have previously been demonstrated as a promising platform for high temperature sensing. However, the density of gratings that could be written on a single fiber was limited by undesired reflections associated with higher order modes in these high numerical aperture fibers. This resulted in a complex, broadband reflection spectrum with limited multiplexing capability. In this work we utilize modifications to the fine structure of the suspended core optical fibers to fine tune the relative confinement loss of the optical fiber modes, thus reducing the contribution from such higher order modes. The effects of these changes on mode propagation are modeled, giving a range of fibers with different confinement loss properties which can be tailored to the specific length scale of a desired application. We achieve single-peak reflections from in idual fiber Bragg gratings, significantly improving performance for multipoint sensing and demonstrate this technique by writing 20 gratings onto a single fiber.
Publisher: Elsevier BV
Date: 03-2011
Publisher: Optica Publishing Group
Date: 26-03-2021
DOI: 10.1364/PRJ.415902
Abstract: A new approach to optical fiber sensing is proposed and demonstrated that allows for specific measurement even in the presence of strong noise from undesired environmental perturbations. A deep neural network model is trained to statistically learn the relation of the complex optical interference output from a multimode optical fiber (MMF) with respect to a measurand of interest while discriminating the noise. This technique negates the need to carefully shield against, or compensate for, undesired perturbations, as is often the case for traditional optical fiber sensors. This is achieved entirely in software without any fiber postprocessing fabrication steps or specific packaging required, such as fiber Bragg gratings or specialized coatings. The technique is highly generalizable, whereby the model can be trained to identify any measurand of interest within any noisy environment provided the measurand affects the optical path length of the MMF’s guided modes. We demonstrate the approach using a sapphire crystal optical fiber for temperature sensing under strong noise induced by mechanical vibrations, showing the power of the technique not only to extract sensing information buried in strong noise but to also enable sensing using traditionally challenging exotic materials.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2023
Publisher: Elsevier BV
Date: 03-2022
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2022
Publisher: The Optical Society
Date: 27-07-2016
DOI: 10.1364/OE.24.017860
Publisher: Optica Publishing Group
Date: 29-09-2009
DOI: 10.1364/OE.17.018533
Publisher: Elsevier BV
Date: 12-2021
Publisher: MDPI AG
Date: 24-10-2023
DOI: 10.3390/BIOS13110949
Publisher: OSA
Date: 2016
Publisher: SPIE
Date: 23-04-2017
DOI: 10.1117/12.2265205
Publisher: SPIE
Date: 02-06-2014
DOI: 10.1117/12.2059155
Publisher: SPIE
Date: 17-10-2012
DOI: 10.1117/12.966847
Publisher: The Optical Society
Date: 25-01-2019
DOI: 10.1364/OL.44.000626
Publisher: AIP Publishing
Date: 10-2022
DOI: 10.1063/5.0102071
Abstract: The on-chip detection of fluorescent light is essential for many bioanalytical and life-science related applications. Here, the optofluidic light cage consisting of a sparse array of micrometer encircling a hollow core represents an innovative concept, particularly for on-chip waveguide-based spectroscopy. In the present work, we demonstrate the potential of the optofluidic light cage concept in the context of integrated on-chip fluorescence spectroscopy. Specifically, we show that fluorescent light from a dye-doped aqueous solution generated in the core of a nanoprinted dual-ring light cage can be efficiently captured and guided to the waveguide ports. Notably, the fluorescence collection occurs predominantly in the fundamental mode, a property that distinguishes it from evanescent field-based waveguide detection schemes that favor collection in higher-order modes. Through exploiting the flexibility of waveguide design and 3D nanoprinting, both excitation and emission have been localized in the high transmission domains of the fundamental core mode. Fast diffusion, detection limits comparable to bulk measurements, and the potential of this approach in terms of device integration were demonstrated. Together with previous results on absorption spectroscopy, the achievements presented here suggest that the optofluidic light cage concept defines a novel photonic platform for integrated on-chip spectroscopic devices and real-time sensors compatible with both the fiber circuitry and microfluidics. Applications in areas such as bioanalytics and environmental sciences are conceivable, while more sophisticated applications such as nanoparticle tracking analysis and integrated Raman spectroscopy could be envisioned.
Publisher: IEEE
Date: 2011
Publisher: Optica Publishing Group
Date: 09-05-2022
DOI: 10.1364/OL.456552
Abstract: In this paper, a highly sensitive temperature compensated fiber optic magnetic field sensor by Sagnac and Mach–Zehnder combination interference (SMZI) is proposed and verified. The sensing structure relies on microstructured exposed core fiber (ECF) filled with ethanol and magnetic fluid (MF). The refractive index of MF and ethanol is affected by the magnetic field and temperature (MFT). SMZI is based on the multimode and birefringence characteristics of ECF. The measurement principle is that the spectra of Sagnac interference and Mach–Zehnder interference have respective sensitivities to the MFT. The magnetic sensitivity can reach 1.17 nm/mT, and the temperature sensitivity is up to –1.93 nm/°C. At the same time, the sensor has good repeatability and low detection limits of 0.41 mT and 0.25°C, respectively. It not only solves the cross-influence of temperature but also makes the spectral analysis more intuitive. The sensor has a broad development prospect in the application of MFT detection.
Publisher: Optica Publishing Group
Date: 2007
DOI: 10.1364/OE.15.017891
Abstract: We develop a generic model of excitation and fluorescence recapturing within filled microstructured optical fibres (MOFs) with arbitrary structure and demonstrate that the light-matter overlap alone does not determine the optimal fibre choice. Fibre designs with sub-wavelength features and high-index glasses exhibit localised regions of high intensity, and we show that these regions can lead to approximately two orders of magnitude enhancement of fluorescence recapturing. Here we show how this regime can be exploited for sensing and demonstrate experimentally in-fibre excitation and fluorescence recapturing within a filled, solid-core MOF.
Publisher: Elsevier BV
Date: 11-2018
Publisher: The Optical Society
Date: 02-12-2014
DOI: 10.1364/OME.4.000029
Publisher: MDPI AG
Date: 30-09-2013
DOI: 10.3390/S131013163
Publisher: IEEE
Date: 10-2018
Publisher: Elsevier BV
Date: 05-2018
Publisher: IEEE
Date: 07-2017
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-11-2019
Publisher: Wiley
Date: 29-09-2023
DOI: 10.1002/POL.20230481
Publisher: The Optical Society
Date: 15-01-2014
DOI: 10.1364/OE.22.001480
Publisher: The Optical Society
Date: 10-12-2018
DOI: 10.1364/OE.26.033604
Publisher: Wiley
Date: 06-10-2020
Publisher: Trans Tech Publications, Ltd.
Date: 06-2013
DOI: 10.4028/WWW.SCIENTIFIC.NET/KEM.558.522
Abstract: This paper summarises recent work conducted on the development of exposed core microstructured optical fibres for distributed corrosion sensing. Most recently, exposed-core fibres have been fabricated in silica glass, which is known to be reliable under a range of processing and service environments. We characterise the stability of these new silica fibres when exposed to some typical sensing and storage environments. We show the background loss to be the best achieved to date for exposed-core fibres, while the transmission properties are up to ~2 orders of magnitude better than for the previously reported exposed-core fibres produced in soft glass. This provides a more robust fibre platform for corrosion sensing conditions and opens up new opportunities for distributed optical fibre sensors requiring long-term application in harsh environments.
Publisher: OSA
Date: 2016
Publisher: MDPI AG
Date: 08-08-2014
DOI: 10.3390/S140814488
Publisher: American Chemical Society (ACS)
Date: 22-07-2021
Publisher: The Optical Society
Date: 03-08-2016
DOI: 10.1364/OE.24.018541
No related grants have been discovered for Stephen Warren-Smith.