ORCID Profile
0000-0003-4141-2813
Current Organisation
University of South Australia
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Publisher: American Chemical Society (ACS)
Date: 02-07-2010
DOI: 10.1021/JP103454R
Publisher: Proceedings of the National Academy of Sciences
Date: 06-02-2012
Publisher: Elsevier BV
Date: 09-2020
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: American Chemical Society (ACS)
Date: 19-07-2003
DOI: 10.1021/JP022248B
Publisher: Optica Publishing Group
Date: 28-03-2022
DOI: 10.1364/OE.452945
Abstract: Coupling characteristics between a single mode fiber (SMF) and a waveguide embedded in a glass chip via a graded index fiber (GIF) tip are investigated at a wavelength of 976 nm. The GIF tips comprise a coreless fiber section and a GIF section. A depressed cladding waveguide in a ZBLAN glass chip with a core diameter of 35 μm is coupled with GIF tips that have a range of coreless fiber and GIF lengths. An experimental coupling efficiency as high as 88% is obtained while a numerical simulation predicts 92.9% for the same GIF tip configuration. Since it is measured in the presence of Fresnel reflection, it can be further improved by anti-reflection coating. Additionally, it is demonstrated that a gap can be introduced between the chip waveguide and the GIF tip while maintaining the high coupling efficiency, thus allowing a thin planar optical component to be inserted. The results presented here will enable miniaturization and simplification of photonic chips with integrated waveguides by replacing bulk coupling lenses with integrated optical fibers.
Publisher: AIP Publishing
Date: 11-2019
DOI: 10.1063/1.5113624
Publisher: Hindawi Limited
Date: 2017
DOI: 10.1155/2017/4879528
Abstract: Defects within optical fibers can cause premature failure in fiber-based systems and must be detected early to avoid performance degradation. Addressing this need can ensure that no defective optical fibers are being used by end users and improve processes to reduce the number of defects during manufacturing. The main challenge to date has been developing a technique that can measure defects along long lengths of fiber, within opaque packaging, and with position information. We demonstrate a simple and novel technique for detecting and radially resolving microscopic defects in packaged/buried fibers using an angle-resolved interrogator that analyzes the transmission of different ray groups. We have measured the accuracy to be as low as ±2 μ m, which is sufficient for most fibers that have diameters in the order of ~100 μ m.
Publisher: CSIRO Publishing
Date: 2003
DOI: 10.1071/CH03011
Abstract: Resonance-enhanced 266 nm 1 + 1 multiphoton ionization has been used in conjunction with a liquid microjet time-of-flight mass spectrometer to explore the photochemistry of a 10–3 M solution of anisole in ethanol. Only ions generated in the condensed phase originating from the three-photon non-resonant ionization of the ethanol solvent are liberated into the vacuum. No solute ions generated in solution are observed unless the concentration is increased to 1 M. Under high concentration conditions, solute pairing or aggregation at the liquid surface is a necessary precursor towards liberating solute photoions into the vacuum via a Coulombic explosion. At a solution concentration of 10–3 M, a decreased solute ion density at the liquid surface is insufficient to initiate a Coulombic explosion into the vacuum. Rather, non-resonantly generated solvent ions on the liquid surface dominate the ion ejection process. Related studies on 10–3 M solutions of 4-methoxyphenol in both ethanol and water show that at this concentration solute ionization is most likely to be observed following thermal evaporation from the surface of a liquid beam.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 15-04-2019
Publisher: Elsevier BV
Date: 12-2007
Publisher: IEEE
Date: 10-2018
Publisher: Proceedings of the National Academy of Sciences
Date: 10-01-2012
Abstract: Adsorption of aqueous thiocyanate ions from bulk solution to the liquid/vapor interface was measured as a function of temperature by resonant UV second harmonic generation spectroscopy. The resulting adsorption enthalpy and entropy changes of this prototypical chaotrope were both determined to be negative. This surprising result is supported by molecular simulations, which clarify the microscopic origins of observed thermodynamic changes. Calculations reveal energetic influences of adsorbed ions on their surroundings to be remarkably local. Negative adsorption enthalpies thus reflect a simple repartitioning of solvent density among surface, bulk, and coordination regions. A different, and much less spatially local, mechanism underlies the concomitant loss of entropy. Simulations indicate that ions at the interface can significantly bias surface height fluctuations even several molecular diameters away, imposing restrictions consistent with the scale of measured and computed adsorption entropies. Based on these results, we expect an ion’s position in the Hofmeister lyotropic series to be determined by a combination of driving forces associated with the pinning of capillary waves and with a competition between ion hydration energy and the neat liquid’s surface tension.
Publisher: MDPI AG
Date: 27-12-2022
DOI: 10.3390/PHOTONICS10010027
Abstract: A readily configurable and scalable 2 µm laser source with multi-channel/wavelength fiber output could be advantageous to 2 µm applications such as spectral-beam combination or fiber communications. We report the first experimental realization and characterization of a two-channel holmium-doped zirconium fluoride glass waveguide array laser pumped by a single thulium fiber laser at 1945 nm. Specific laser wavelengths are selected by fiber Bragg gratings (2076.7 nm and 2074.4 nm), and single channel powers of mW are achieved. Design and assembly details, and considerations for future improvements are discussed, including the potential extension to and beyond a 12 channel source.
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2541105
Publisher: Elsevier BV
Date: 10-2014
Publisher: Elsevier BV
Date: 2012
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2541295
Publisher: Proceedings of the National Academy of Sciences
Date: 08-09-2009
Abstract: Recent experimental and theoretical results have firmly established the existence of enhanced concentrations of selected ions at the air/water interface. Ion adsorption to aqueous interfaces involving complex organic molecules is relevant to biology in connection with the familiar but incompletely understood Hofmeister effects. Here, we describe resonant UV second harmonic generation (SHG) studies of the strongly chaotropic thiocyanate ion adsorbed to the interface formed by water and a monolayer of dodecanol, wherein the Gibbs free energy of adsorption was determined to be −6.7 ± 1.1 and −6.3 ± 1.8 kJ/mol for sodium and potassium thiocyanate, respectively, coincident with the value determined for thiocyanate at the air/water interface. Interestingly, near 4 M and higher concentrations, the resonant SHG signal increases discontinuously, indicating a structural change in the interfacial region.
Publisher: SPIE
Date: 30-12-2019
DOI: 10.1117/12.2540463
Publisher: Springer Science and Business Media LLC
Date: 10-07-2018
DOI: 10.1038/S41598-018-28631-3
Abstract: There is a deficiency of low-loss microstructured waveguides that can be fabricated with a single laser-pass to minimize stress build-up, which can enable enhanced functionality and higher compactness for integrated optical devices. We demonstrate, for the first time, a series of multi-ring claddings each with a pair of cores in BK7 glass. Each waveguide was fabricated using only a single laser-pass at 1 MHz pulse repetition rate, 5 mm/s translation speed, 250 fs pulse width, over a set of pulse energies. We obtained the lowest-reported propagation loss of 0.062 dB/cm, measured at 1155 nm wavelength from the waveguide written with 340 nJ pulse energy. The maximum observed numerical aperture is 0.020, measured at 1155 nm wavelength from the waveguide written with 620 nJ pulse energy. Such waveguides could be incorporated in integrated Raman laser platforms for biomedical applications.
Publisher: OSA
Date: 2019
Publisher: Optica Publishing Group
Date: 2020
DOI: 10.1364/CLEOPR.2020.C12B_3
Abstract: We propose a method to significantly reduce speckle originating from the intrinsic coherence of a supercontinuum laser used for reflectance spectroscopy. Rotating the s les and spectral averaging reveals the characteristic spectra of two minerals.
Publisher: SPIE
Date: 08-03-2023
DOI: 10.1117/12.2649429
Publisher: Springer Science and Business Media LLC
Date: 23-02-2017
DOI: 10.1038/SREP42997
Abstract: Numerous articles have recently reported on gas seepage offshore Svalbard, because the gas emission from these Arctic sediments was thought to result from gas hydrate dissociation, possibly triggered by anthropogenic ocean warming. We report on findings of a much broader seepage area, extending from 74° to 79°, where more than a thousand gas discharge sites were imaged as acoustic flares. The gas discharge occurs in water depths at and shallower than the upper edge of the gas hydrate stability zone and generates a dissolved methane plume that is hundreds of kilometer in length. Data collected in the summer of 2015 revealed that 0.02–7.7% of the dissolved methane was aerobically oxidized by microbes and a minor fraction (0.07%) was transferred to the atmosphere during periods of low wind speeds. Most flares were detected in the vicinity of the Hornsund Fracture Zone, leading us to postulate that the gas ascends along this fracture zone. The methane discharges on bathymetric highs characterized by sonic hard grounds, whereas glaciomarine and Holocene sediments in the troughs apparently limit seepage. The large scale seepage reported here is not caused by anthropogenic warming.
Location: United States of America
No related grants have been discovered for Dale Otten.