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Item Metadata only Mid-Infrared PolarizationMaintaining Photonic Crystal Fiber(2022) Ebendorff-Heidepriem, H.; Chenard, F.; Schartner, E.; Alvarez, O.; Radionova, A.; 7th International Workshop on Speciality Optical Fibers (WSOF) (12 Dec 2022 - 12 Dec 2022 : Adelaide)Item Metadata only Visualisation of glass flow during extrusion to track glass deformations(2022) Ebendorff-Heidepriem, H.; Radionova, A.; Schartner, E.; 7th International Workshop on Speciality Optical Fibers (11 Dec 2022 - 16 Dec 2022Item Metadata only Speciality optical glasses & fibre: fabrication & applications(2022) Radionova, A.; Australian Institute of Physics Congress (AIP) ANFF Pre Conference Workshop (11 Dec 2022 - 11 Dec 2022 : Adelaide)Item Metadata only 3D glass printing for fibre preforms(2022) Radionova, A.; Australian Institute of Physics Congress (AIP) ANFF Pre Conference Workshop (11 Dec 2022 - 11 Dec 2022 : Adelaide)Item Metadata only A Method for in Vivo Quantification of Cytokine IL-1β in the Rat Intrathecal Space(American Chemical Society, 2020) Deng, F.; Arman, A.; Goldys, E.M.; Hutchinson, M.R.; Liu, G.IL-1β is a potent pro-inflammatory cytokine critical to multiple pathologies in the central nervous system (CNS). Quantification of IL-1β in vivo is challenging due to pM range of IL-1β released in the spinal cord and also the terminal nature of cerebrospinal fluid (CSF) sampling in rodents. Herein we developed a robust in vivo device on stainless steel suitable for detection of IL-1β in the spinal cord of rats. This approach offers high sensitivity (3.2 pg mL–1) and specificity to IL-1β. Also, a modified lumbar puncture method was employed to implant the device in the intrathecal space of male Sprague–Dawley (SD) rats under short-acting anesthesia, allowing minimal invasiveness, which provided the possibility of repeated measurement of IL-1β in the same animal. Our biosensing technology and the surgical method provide a universal platform for in vivo detection of diverse analytes in longitudinal, within-subject studies in the intrathecal space of rats to reduce the required number of experimental animals.Item Open Access Monolithic Photonic Integrated Circuit Based on Silicon Nitride and Lithium Niobate on Insulator Hybrid Platform(Wiley-VCH, 2022) Jiang, Y.; Han, X.; Huang, H.; Zhang, P.; Dubey, A.; Xiao, H.; Yuan, M.; Frigg, A.; Thach, G.N.; Boes, A.; Li, Y.; Ren, G.; Su, Y.; Mitchell, A.; Tian, Y.Lithium niobate on insulator (LNOI) has been demonstrated as a promising platform for photonic integrated circuits (PICs), thanks to its excellent properties such as strong electro-optic effect, low material loss, and wide transparency window. Herein, a monolithic PIC for high-speed data communication application on a lithium-niobate-etchless platform with silicon nitride (Si₃N₄) as a loading material is proposed and demonstrated. The fabricated PIC consists of four racetrack resonator modulators and a pair of four-channel mode (de)multiplexers, which shows high data modulation rate of 70 Gbps for single channel and the total data throughput reaches up to 280 Gbps. To the best of knowledge, this is the first demonstration of PIC consisting of high-speed electro-optical modulators and (de)multiplexers with such high data capacity on Si₃N₄-LNOI hybrid platform, which opens up new avenues for achieving large-scale monolithic integration on LNOI platform in future.Item Open Access Saos-2 cells cultured under hypoxia rapidly differentiate to an osteocyte-like stage and support intracellular infection by Staphylococcus aureus.(Wiley, 2023) Zelmer, A.R.; Starczak, Y.; Solomon, L.B.; Richter, K.; Yang, D.; Atkins, G.J.The intracellular infection of osteocytes represents a clinically important aspect of osteomyelitis. However, few human osteocyte in vitro models exist and the differentiation of immature osteoblasts to an osteocyte stage typically takes at least 4-weeks of culture, making the study of this process challenging and time consuming. The osteosarcoma cell line Saos-2 has proved to be a useful model of human osteoblast to mature osteocyte differentiation. Culture under osteogenic conditions in a standard normoxic (21% O2) atmosphere results in reproducible mineralization and acquisition of mature osteocyte markers over the expected 28–35day culture period. In order to expedite experimental assays, we tested whether reducing available oxygen to mimic concentrations experienced by osteocytes in vivo would increase the rate of differentiation. Cells cultured under 1% O2 exhibited maximal mineral deposition by 14days. Early (COLA1, MEPE) and mature (PHEX, DMP1, GJA1, SOST) osteocyte markers were upregulated earlier under hypoxia compared to normoxia. Cells differentiated under 1% O2 for 14days displayed a similar ability to internalize Staphylococcus aureus as day 28 cells grown under normoxic conditions. Thus, low oxygen accelerates Saos-2 osteocyte differentiation, resulting in a useful human osteocyte-like cell model within 14 days.Item Open Access UV emission from lanthanide-doped upconversion nanoparticles in super-resolution microscopy: potential for cellular damage(American Chemical Society, 2023) Karami, A.; de Prinse, T.J.; Spooner, N.A.; Kidd, S.P.; Sumby, C.J.; Bi, J.Upconversion nanoparticles (UCNPs) co-doped with lanthanide ions have recently attracted significant attention as fluorescent probes for super-resolution microscopy (SRM). This is due to the advantages of UCNPs over other fluorescence probes, such as fluorescent proteins, owing to their unique optical properties, limited photobleaching, and sharp emissions. However, the concurrent emission of ultraviolet (UV) wavelength radiation by UCNPs and the potential for cell photodamage, which may limit useful live-cell analysis, have been overlooked. Here, UCNPs synthesized with eight commonly used combinations of Yb/Tm and Yb/Tm/Gd dopants were excited by either pulsed- or continuous-wave (CW) lasers to evaluate their UV emission. The ratio of emitted UV-A and UV-B was measured relative to blue emission at 475 nm, which is traditionally used for imaging during SRM. We demonstrate that most UCNP samples emit UV light and that the dopant concentration has a key role in generating UV emissions. In addition, the use of pulsed or CW lasers for excitation can lead to a large variation in the amount of UV emitted. This work highlights the importance of considering upconversion dopant composition and concentration, as well as analyzing the emission of synthesized UCNPs before their use to prevent unwanted cell photodamage during live-cell imaging by SRM. Moreover, it established a need to improve the visible light emission of UCNPs with respect to UV emission for SRM applications.Item Open Access Dual Laser Study of Non-Degenerate Two Wavelength Upconversion Demonstrated in Sensitizer-Free NaYF₄:Pr Nanoparticles(Wiley, 2021) de Prinse, T.J.; Karami, A.; Moffatt, J.E.; Payten, T.B.; Tsiminis, G.; Teixeira, L.D.S.; Bi, J.; Kee, T.W.; Klantsataya, E.; Sumby, C.J.; Spooner, N.A.Understanding the upconversion pathways of a rare-earth dopant is crucial to furthering the use of that material, either toward applications in imaging or elsewhere. This work outlines a new analysis approach that consists of using two synchronized widely-tunable laser sources to explore the properties of upconverting materials. By examining sensitizer-free rare-earth nanoparticles based on a matrix of hexagonal sodium yttrium tetrafluoride (β-NaYF4) doped with praseodymium but no ytterbium sensitizer, a “non-degenerate” two-color upconversion fluorescence at a combined excitation of 1020–850 nm is shown. This insight demonstrates the ability of this technique to locate and interrogate novel upconversion pathways. The dopant level of the nanoparticles could be modified without altering other factors, such as the particle's shape or size, that would also change optical properties and this allows investigation of the dopant-level dependency of the optical properties. The approach also allows exploration of the time delay domain between the arrival times of the two non-degenerate excitation pulses, which allows modulation of the brightness from the visible light emissions. This work opens up the parameter space for the systematic synthesis and characterization of new materials with non-degenerate upconversion emission.Item Open Access Terahertz hollow core antiresonant fiber with metamaterial cladding(MDPI AG, 2020) Sultana, J.; Islam, M.S.; Cordeiro, C.M.B.; Dinovitser, A.; Kaushik, M.; Ng, B.W.H.; Abbott, D.A hollow core antiresonant photonic crystal fiber (HC-ARPCF) with metal inclusions is numerically analyzed for transmission of terahertz (THz) waves. The propagation of fundamental and higher order modes are investigated and the results are compared with conventional dielectric antiresonant (AR) fiber designs. Simulation results show that broadband terahertz radiation can be guided with six times lower loss in such hollow core fibers with metallic inclusions, compared to tube lattice fiber, covering a single mode bandwidth (BW) of 700 GHz.Item Open Access Exploring Photoswitchable Binding Interactions with Small Molecule- and Peptide-Based Inhibitors of Trypsin(Wiley, 2023) Palasis, K.; Peddie, V.; Turner, D.; Zhang, X.; Yu, J.; Abell, A.D.The ability to photochemically activate a drug, both when and where needed, requires optimisation of the difference in biological activity between each isomeric state. As a step to this goal, we report small molecule and peptide-based inhibitors of the same protease - trypsin - to better understand how photoswitchable drugs interact with their biological target. The best peptidic inhibitor displayed a >5-fold difference in inhibitory activity between isomeric states, whereas the best small molecule inhibitor only showed a 3.4-fold difference. Docking and molecular modelling suggests this result is due to a large change in 3D structure in the key binding residues of the peptidic inhibitor upon isomerisation, which is not observed for the small molecule inhibitor. Hence, we demonstrate that significant structural changes in critical binding motifs upon irradiation are essential for maximising the difference in biological activity between isomeric states. This is an important consideration in the design of future photoswitchable drugs for clinical applications.Item Metadata only Multiple beam coherent combination via an optical ring resonator(Optical Society of America, 2023) Bode, N.; Holmes, Z.; Ng, S.; vonBehren, B.; Ottaway, D.; Willke, B.Future gravitational wave detectors (GWDs) require low noise, single frequency, continuous wave lasers with excellent beam quality and powers in excess of 500 W. Low noise laser amplifiers with high spatial purity have been demonstrated up to 300 W. For higher powers, coherent beam combination can overcome scaling limitations. In this Letter we introduce a new, to the best of our knowledge, combination scheme that uses a bow-tie resonator to combine three laser beams with simultaneous spatial filtering performance.Item Metadata only Label-free DNA quantification using isothermal amplification on an exposed core optical fiber microfluidic platform(Royal Society of Chemistry, 2023) Li, X.; Zhang, H.; Zhang, Y.; Zhao, Y.; Nguyen, L.V.; Zhou, X.; Warren-Smith, S.C.Isothermal amplification technology has triggered 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 reliable widescale testing is critical to outbreak management. In this paper, a label-free isothermal deoxyribonucleic acid (DNA) amplification method based on refractive index (RI) quantification is proposed and demonstrated for the first time by combining optical fiber sensing, microfluidics, and isothermal amplification. A highly RI-sensitive Mach-Zehnder (MZ) interference is formed by splicing a short length of an exposed-core fiber between two lengths of a single-mode fiber while the microfluidic liquid channel on the exposed side of the ECF is filled with target DNA and the amplification solution. Real-time quantitative measurement of the target DNA is then realized by monitoring the change in RI of the solution during the isothermal DNA amplification process. The experimental results show that the platform successfully realizes real-time label-free monitoring of isothermal amplification of 0.16 aM DNA samples. This method is a breakthrough for applications in the fields of DNA detection and quantification where simple operation, rapid detection, portability, small size, high selectivity, and high sensitivity are required.Item Open Access Investigation of refractive index dynamics during in vitro embryo development using off-axis digital holographic microscopy(Optical Society of America, 2023) Dwapanyin, G.O.; Chow, D.J.X.; Tan, T.C.Y.; Dubost, N.S.; Morizet, J.M.; Dunning, K.R.; Dholakia, K.Embryo quality is a crucial factor affecting live birth outcomes. However, an accurate diagnostic for embryo quality remains elusive in the in vitro fertilization clinic. Determining physical parameters of the embryo may offer key information for this purpose. Here, we demonstrate that digital holographic microscopy (DHM) can rapidly and non-invasively assess the refractive index of mouse embryos. Murine embryos were cultured in either low- or high-lipid containing media and digital holograms recorded at various stages of development. The phase of the recorded hologram was numerically retrieved, from which the refractive index of the embryo was calculated. We showed that DHM can detect spatio-temporal changes in refractive index during embryo development that are reflective of its lipid content. As accumulation of intracellular lipid is known to compromise embryo health, DHM may prove beneficial in developing an accurate, non-invasive, multimodal diagnostic.Item Metadata only Nanoporous anodic alumina-based iontronics: fundamentals and applications(Royal Society of Chemistry (RSC), 2023) Wang, J.; Vu, K.N.; Abell, A.D.; Santos, A.; Law, C.S.Synthetic iontronic systems harness ions as elementary carriers to perform functions that mimic those of biological systems; such as information transduction, sensing, and energy generation. The underlying principle of synthetic iontronics is to control the concentration, depletion, flow, and spatial and temporal distribution of ions when these flow along engineered nanochannels. Synthetic iontronic materials enable unique forms of ion transport phenomena such as rectification and switching, which resemble those of solid-state electronics. Nanoporous anodic alumina (NAA) is a versatile material with tailorable structural and chemical properties that provides an ideal platform for developing a range of iontronic devices. NAA membranes exhibit both intrinsic and extrinsic ionic rectification properties, where the former has recently been associated with the presence of its anodic oxide barrier oxide layer at the bottom tips of its nanopores, and the latter can be achived by engineering its structure and through surface chemistry modifications. This review provides a comprehensive overview of NAA as an iontronic platform material, from its intrinsic and extrinsic properties to proof-of-concept demonstrations of NAAbased iontronic systems for applications such as ionic diodes, bio- and chemical sensing, and osmotic energy generation.Item Metadata only Experimental and Theoretical Study of Dynamic Polarizabilities in the 5S1/2–5D5/2 Clock Transition in Rubidium-87 and Determination of Electric Dipole Matrix Elements(American Physical Society (APS), 2023) Hamilton, R.; Roberts, B.M.; Scholten, S.K.; Locke, C.; Luiten, A.N.; Ginges, J.S.M.; Perrella, C.The interaction between light and an atom causes perturbations in the atom’s energy levels, known as the light shift. These light shifts are a key source of inaccuracy in atomic clocks, and can also deteriorate their precision. We present a study of light shifts and associated dynamic polarizabilities for a two-photon atomic clock based on the 5S1/2–5D5/2 transition in rubidium-87 over the range 770–800 nm. We determine experimental and theoretical values for a magic wavelength in this range and the electric dipole (E1) matrix element for the 5P3/2–5D5/2 transition. We find a magic wavelength of 776.179(5) nm (experimental) and 776.21 nm (theoretical) in the vicinity of the 5P3/2–5D5/2 resonance, and the corresponding reduced E1 matrix element 1.80(6)ea0 (experimental) and 1.96(15)ea0 (theoretical). These values resolve a previous discrepancy between theory and experiment.Item Open Access Correlated twin-photon generation in a silicon nitride loaded thin film PPLN waveguide(Optica Publishing Group, 2023) Henry, A.; Barral, D.; Zaquine, I.; Boes, A.; Mitchell, A.; Belabas, N.; Bencheikh, K.Photon-pair sources based on thin film lithium niobate on insulator technology have a great potential for integrated optical quantum information processing. We report on such a source of correlated twin-photon pairs generated by spontaneous parametric down conversion in a silicon nitride (SiN) rib loaded thin film periodically poled lithium niobate (LN) waveguide. The generated correlated photon pairs have a wavelength centred at 1560 nm compatible with present telecom infrastructure, a large bandwidth (21 THz) and a brightness of ∼2.5 × 105 pairs/s/mW/GHz. Using the Hanbury Brown and Twiss effect, we have also shown heralded single photon emission, achieving an autocorrelation g (2) H (0) ≃ 0.04.Item Open Access Chronological constraint of Neanderthal cultural and environmental changes in southwestern Europe: MIS 5-MIS 3 dating of the Axlor site (Biscay, Spain)(Wiley, 2023) Demuro, M.; Arnold, L.J.; González-Urquijo, J.; Lazuen, T.; Frochoso, M.The cave site of Axlor (Biscay, Spain) preserves one of the most informative Middle Palaeolithic (MP) records for the North Atlantic Iberian region, though its age remains poorly known. Here we use single‐grain optically stimulated luminescence (OSL) and single‐grain thermally transferred OSL (TT‐OSL) dating of sediments to improve the age constraint of Axlor's MP succession (levels N–B). Our new ages are consistent with the previously published terminus ante quem 14C ages for the site (>42.9 cal ka BP), and suggest the sequence accumulated during a period of ~50 kyr. Axlor's levels N–F were deposited ~100–80 ka, probably during marine isotope stage (MIS) 5d–a, while levels D and B were deposited ~70 and ~50 ka, respectively, during MIS 4 and mid‐MIS 3. Our results indicate that major faunal and technological turnovers occurred towards the end of MIS 5, potentially coinciding with broader environmental and climatic changes. Axlor's Quina record, dated here to the onset of MIS 4, is one of the oldest in Europe. Comparisons with neighbouring sites point to complex regional chronologies and development for this particular behaviour, though detailed correlations with other MP sequences remain difficult due to their poor chronological attributes. The present study highlights the important role that single‐grain optical dating can play in elucidating the broader evolution of the MP across southwestern Europe.Item Metadata only Optical transport over millimeter distances of a microscopic particle using a novel all-fiber Bessel-like beam generator(Elsevier, 2023) Lee, H.; Lee, M.; Lee, H.J.; Yoon, J.; Dholakia, K.; Oh, K.Whilst free space Bessel modes can show particle guidance over extended distances, this has been limited for fiber-based Bessel-like beams which have importance for microfluidic applications. We propose and experimen- tally demonstrate a novel all-fiber Bessel-like beam generator (BBG) that is shown transport a dielectric particle distance in excess of 2mm. This was achieved by optimizing the multimode interference (MMI) in the BBG struc- ture to create a Bessel-like beam of appropriate propagation invariant length (PIL) and judicious choice of laser wavelength suppress thermal effects. By varying the diameter of the region where the MMI occurred we analyzed its impact on PIL and the transverse intensity profile of the Bessel-like beam. Our study paves the way for the fiber optic applications such as novel beam shaping, optical transport, and optical imaging.Item Restricted Present, Past and Future of Glass art and science exhibition(2023) Radionova, A.