See a list of publications below or visit the Photonics academic staff page and click on a particular member of staff to access their personal web page, which includes a list of their own publications.
Results
- Showing results for:
- Reset all filters
Search results
-
Journal articleTawy G, Minassian A, Damzen MJ, 2022,
Volume Bragg Grating Locked Alexandrite Laser
, OPTICS, Vol: 3, Pages: 53-59 -
Journal articleHong W, Dunsby C, 2022,
Automatic tube lens design from stock optics for microscope remote-refocusing systems
, Optics Express, Vol: 30, Pages: 4274-4278, ISSN: 1094-4087The remote-refocusing approach of Botcherby et al. [Opt. Lett. 32, 2007 (2007) [CrossRef] ] has been applied widely to 2D and 3D fluorescence microscopes to enable rapid refocusing of the optical system without mechanically perturbing the sample. In order for this approach to operate correctly, it requires that the overall magnification of the first two microscope systems matches the ratio of the refractive indices in sample and intermedia image spaces. However, commercially available tube lenses are not always suitable to produce the desired overall magnification. Therefore, a practical approach to produce tube lenses with low expense and diffraction-limited performance is required. Tube lenses can be formed using a pair of stock achromatic doublets, however, selecting appropriate pairs of achromatic doublets from stock optics is a time-consuming process, as many combinations can be considered. In this paper, we present two software packages (Catalogue Generator and Doublet Selector) developed in MATLAB that use the application programming interface (ZOS-API) to the Zemax OpticStudio optical design software to realise an automatic search of stock achromatic doublets to produce microscope tube lenses with a specified focal length, entrance pupil diameter and maximum design field angle. An algorithm to optimise principal plane positions in versions of OpticStudio before 20.2 was also introduced to enable the use of older software versions. To evaluate the performance of Catalogue Generator and Doublet Selector, we used them to generate ten tube lens designs. All of the software-produced tube lenses have a better optical performance than those using manually selected pairs of stock doublets lenses.
-
Conference paperMurray RT, Anderson J, Wei J, et al., 2022,
Wavelength tunable mid-infrared generation in non-critically cut CdSiP2 crystals by cascaded optical parametric generation with a nanosecond 1.064 μm Nd:YAG laser
We demonstrate a method to generate wavelength tunable mid-infrared radiation from 3.7-4.3 μm using a nanosecond 1.064 μm Nd:YAG pump at 10 Hz, employing cascaded optical parametric generation in non-critically cut CdSiP2 crystals.
-
Conference paperMunj AH, Kerridge-Johns WR, 2022,
Ring Cavity Vortex Laser using a Wedge-Plate Shearing Interferometer
We construct a compact unidirectional Nd:YVO<inf>4</inf> ring laser generating watt-level vortex beam (LG<inf>01</inf>) output with high mode purity (98%) in a single longitudinal mode. This was enabled through a wedge-plate shearing interferometer (WPSI) acting as a Gaussian to LG<inf>01</inf> mode conversion device and output coupler. This compact and cheap device uses off-the-shelf components. The design could be adapted to any gain medium for wavelength versatility.
-
Conference paperTawy G, Dorrzapf M, Fang Z, et al., 2022,
Blue-Diode-Pumped Alexandrite Laser
We report a blue-diode-pumped Alexandrite laser operating at 754nm with 0.5W of output laser power with an optical efficiency of 20%. We provide a comparison of blue-diode-pumping to red-diode-pumping to show its potential as a low-cost alternative due to the availability of low-cost high-power blue-diodes. A comparison of the laser characteristics is provided as well as a study of the thermal lensing for blue-diode-pumping for the very first time.
-
Conference paperMurray RT, Anderson J, Wei J, et al., 2022,
Wavelength tunable mid-infrared generation in non-critically cut CdSiP2 crystals by cascaded optical parametric generation with a nanosecond 1.064 µm Nd:YAG laser
We demonstrate a method to generate wavelength tunable mid-infrared radiation from 3.7-4.3 µm using a nanosecond 1.064 µm Nd:YAG pump at 10 Hz, employing cascaded optical parametric generation in non-critically cut CdSiP<inf>2</inf> crystals.
-
Journal articleRamuz M, Diakonov I, Dunsby C, et al., 2022,
MultiFRET: A Detailed Protocol for High-Throughput Multiplexed Ratiometric FRET.
, Methods Mol Biol, Vol: 2483, Pages: 33-59The newly generated software plugin MultiFRET allows for real-time measurements of multiplexed fluorescent biosensors in a near high-throughput fashion. Here we describe a detailed protocol for setup and use of this software for any purpose requiring instant feedback during fluorescence measurement experiments. We further describe its non-primary features including beam splitter misalignment correction, custom calculations through input of simple equations typed in a .txt format, customizable Excel output, and offline bulk analysis of image stacks. Finally, we supply a usage example of a cAMP measurement in cultured rat neonatal cardiomyocytes.
-
Conference paperFox MFJ, Bland S, Mangles SPD, et al., 2022,
Expectations of how student views on experimental physics develop during an undergraduate degree
, Physics Education Research Conference (PERC), Publisher: AMER ASSOC PHYSICS TEACHERS, Pages: 182-187, ISSN: 2377-2379 -
Conference paperCodescu M-A, Weiß M, Brehm M, et al., 2022,
Ultrafast Proton Transfer Pathways Mediated by Imidazole
, International Conference on Ultrafast Phenomena, Publisher: Optica Publishing Group, Pages: Tu1A.4-Tu1A.4<jats:p>We explore with ultrafast infrared spectroscopy and molecular dynamics simulations how imidazole, an amphoteric molecule that can act both as acid and as base, provides alternate proton transfer pathways in the tautomerization reaction of 7-hydroxyquinoline.</jats:p>
-
Conference paperBattle RA, Chandran AM, Runcorn TH, et al., 2022,
Optical parametric amplification seeded by four-wave mixing in photonic crystal fibers
, Conference on Nonlinear Frequency Generation and Conversion - Materials and Devices XXI at SPIE LASE Conference, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X -
Journal articleKalita R, Flanagan W, Lightley J, et al., 2021,
Single-shot phase contrast microscopy using polarisation-resolved differential phase contrast
, JOURNAL OF BIOPHOTONICS, Vol: 14, ISSN: 1864-063X- Cite
- Citations: 10
-
Journal articleChandran A, Battle RA, Murray RT, et al., 2021,
Watt-level 743 nm source by second-harmonic generation of a cascaded phosphosilicate Raman fiber amplifier
, Optics Express, Vol: 29, Pages: 41467-41474, ISSN: 1094-4087We demonstrate a nanosecond pulsed 743 nm source through second-harmonic generation of a cascaded phosphosilicate Raman fiber amplifier system operating at 1485 nm. The amplifier is pumped by a 1240 nm phosphosilicate Raman fiber amplifier and seeded with a continuous-wave 1485 nm diode. This 1485 nm light is used for second-harmonic generation in periodically poled lithium niobate. Greater than 1 W of average power is generated at 743 nm with a corresponding pulse energy of 220 nJ at a repetition rate of 5 MHz. The source displays excellent beam quality (M2𝑥,𝑦 ≤ 1.18) with ideal parameters for biomedical imaging applications.
-
Journal articleFotiadi AA, Korobko DA, Zolotovskii IO, et al., 2021,
Brillouin-like amplification in rare-earth-doped optical fibers
, OPTICS EXPRESS, Vol: 29, Pages: 40345-40359, ISSN: 1094-4087- Cite
- Citations: 8
-
Journal articleGuglielmi L, Heliot C, Kumar S, et al., 2021,
Smad4 controls signaling robustness and morphogenesis by differentially contributing to the Nodal and BMP pathways
, NATURE COMMUNICATIONS, Vol: 12- Cite
- Citations: 7
-
Journal articleWright T, Sparks H, Paterson C, et al., 2021,
Video-rate remote refocusing through continuous oscillation of a membrane deformable mirror
, Journal of Physics: Photonics, Vol: 3, Pages: 1-14, ISSN: 2515-7647This paper presents the use of a deformable mirror (DM) configured to rapidly refocus a microscope employing a highnumerical aperture objective lens. An Alpao DM97-15 membrane DM was used to refocus a 40×/0.80 NA water-immersionobjective through a defocus range of -50 to 50 m at 26.3 sweeps per second. We achieved imaging with a mean Strehlmetric of > 0.6 over a field of view in the sample of 200×200 m2 over a defocus range of 77 m. We describe anoptimisation procedure where the mirror is swept continuously in order to avoid known problems of hysteresis associatedwith the membrane DM employed. This work demonstrates that a DM-based refocusing system could in the future be used inlight-sheet fluorescence microscopes to achieve video-rate volumetric imaging.
-
Conference paperWysoczanski R, Baker J, Fenwick P, et al., 2021,
Image analysis of tissue macrophages to confirm differential phagocytosis between groups by microscopy and automated bacterial quantification
, Publisher: EUROPEAN RESPIRATORY SOC JOURNALS LTD, ISSN: 0903-1936- Author Web Link
- Cite
- Citations: 1
-
Journal articleGarcia E, Lightley J, Kumar S, et al., 2021,
Application of direct stochastic optical reconstruction microscopy (dSTORM) to the histological analysis of human glomerular disease
, JOURNAL OF PATHOLOGY CLINICAL RESEARCH, Vol: 7, Pages: 438-445- Cite
- Citations: 8
-
Journal articleGeberbauer J, Kerridge-Johns W, Damzen M, 2021,
> 30 W vortex LG₀₁ or HG₁₀ laser using a modetransforming output coupler
, Optics Express, Vol: 29, Pages: 29082-29094, ISSN: 1094-4087High-power vortex light generated directly from lasers will help drive theirapplications in material processing, optical manipulation, levitation, particle acceleration, andcommunications, but limited power has been achieved to date. In this work, we demonstraterecord vortex average power of 31.3 W directly from a laser, to the best of our knowledge,using an interferometric mode transforming output coupler to convert a fundamental modeNd:YVO4 laser into a LG01 vortex output. The vortex laser was Q-switched with up to 600 kHzpulse rate with a high slope efficiency of 62.5% and an excellent LG01 modal purity of 95.2%.We further demonstrate > 30W laser power in a high quality HG10 mode by simple adjustmentof the output coupler. Experimental investigations of varying output coupling transmission arecompared with theory. This successful implementation of the interferometric output coupler ina high power system demonstrates the suitability of the mode transforming method for robustturn-key vortex lasers with high efficiency and high modal purity, with scalable power andpulse rate.
-
Journal articleLightley J, Gorlitz F, Kumar S, et al., 2021,
Robust deep learning optical autofocus system applied to automated multiwell plate single molecule localization microscopy
, JOURNAL OF MICROSCOPY, ISSN: 0022-2720- Cite
- Citations: 12
-
Journal articleQian K, Arichi T, Price A, et al., 2021,
An eye tracking based virtual reality system for use inside magnetic resonance imaging systems
, Scientific Reports, Vol: 11, Pages: 1-17, ISSN: 2045-2322Patients undergoing Magnetic Resonance Imaging (MRI) often experience anxiety and sometimes distress prior to and during scanning. Here a full MRI compatible virtual reality (VR) system is described and tested with the aim of creating a radically different experience. Potential benefits could accrue from the strong sense of immersion that can be created with VR, which could create sense experiences designed to avoid the perception of being enclosed and could also provide new modes of diversion and interaction that could make even lengthy MRI examinations much less challenging. Most current VR systems rely on head mounted displays combined with head motion tracking to achieve and maintain a visceral sense of a tangible virtual world, but this technology and approach encourages physical motion, which would be unacceptable and could be physically incompatible for MRI. The proposed VR system uses gaze tracking to control and interact with a virtual world. MRI compatible cameras are used to allow real time eye tracking and robust gaze tracking is achieved through an adaptive calibration strategy in which each successive VR interaction initiated by the subject updates the gaze estimation model. A dedicated VR framework has been developed including a rich virtual world and gaze-controlled game content. To aid in achieving immersive experiences physical sensations, including noise, vibration and proprioception associated with patient table movements, have been made congruent with the presented virtual scene. A live video link allows subject-carer interaction, projecting a supportive presence into the virtual world.
-
Conference paperGarcia E, Lightley J, Kumar S, et al., 2021,
Application of direct stochastic optical reconstruction microscopy (dSTORM) to the histological analysis of human glomerular disease
, Publisher: SPRINGER, Pages: S142-S142, ISSN: 0945-6317 -
Journal articleXiang Y, Seow KLC, Paterson C, et al., 2021,
Multivariate analysis of Brillouin imaging data by supervised and unsupervised learning
, JOURNAL OF BIOPHOTONICS, Vol: 14, ISSN: 1864-063X -
Journal articleBerk J, Paterson C, Foreman MR, 2021,
Tracking single particles using surface plasmon leakage radiation speckle
, Journal of Lightwave Technology, Vol: 39, Pages: 3950-3960, ISSN: 0733-8724Label free tracking of small bio-particles such as proteins or viruses is of great utility in the study of biological processes, however such experiments are frequently hindered by weak signal strengths and a susceptibility to scattering impurities. To overcome these problems we here propose a novel technique leveraging the enhanced sensitivity of both interferometric detection and the strong field confinement of surface plasmons. Specifically, we show that interference between the field scattered by an analyte particle and a speckle reference field, derived from random scattering of surface plasmons propagating on a rough metal film, enables particle tracking with sub-wavelength accuracy. We present the analytic framework of our technique and verify its robustness to noise through Monte Carlo simulations.
-
Journal articleGong H, Guo W, Neil MAA, 2021,
GPU-accelerated real-time reconstruction in Python of three-dimensional datasets from structured illumination microscopy with hexagonal patterns
, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 379, ISSN: 1364-503X- Cite
- Citations: 20
-
Journal articleBoland MA, Cohen EAK, Flaxman SR, et al., 2021,
Improving axial resolution in Structured Illumination Microscopy using deep learning
, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 379, ISSN: 1364-503XStructured Illumination Microscopy is a widespreadmethodology to image live and fixed biologicalstructures smaller than the diffraction limits ofconventional optical microscopy. Using recent advancesin image up-scaling through deep learning models,we demonstrate a method to reconstruct 3D SIMimage stacks with twice the axial resolution attainablethrough conventional SIM reconstructions. We furtherdemonstrate our method is robust to noise & evaluateit against two point cases and axial gratings. Finally,we discuss potential adaptions of the method tofurther improve resolution.
-
Journal articleParmar V, Singh S, Kumar S, et al., 2021,
Thermo-physical modeling and experimental validation of core-shell nanoparticle fabrication of nickel-titanium (nitinol) alloy
, Optics and Laser Technology, Vol: 138, ISSN: 0030-3992Nickel-titanium (nitinol) is a biocompatible shape memory alloy with hyperelasticity and biocompatibility property. A three-dimensional heat diffusion model was used in conjunction with phase explosion theory to explain the formation of core-shell nanoparticles of nitinol. The diffusion model was used to evaluate the melt-pool temperature in the ablation region, while the phase explosion theory was used to estimate the thermophysical expansion and subsequent fragmentation of molten and vaporized nitinol. The mathematical parameters were formulated in conjunction with the experimental results of pulsed laser ablation of core-shell nitinol nanoparticles of various sizes. The model was further employed to predict the sizes of the nanoparticles produced at other higher fluences and the results were experimentally validated.
-
Journal articleGratus J, Kinsler P, McCall MW, 2021,
Temporary Singularities and Axions: An Analytic Solution that Challenges Charge Conservation
, ANNALEN DER PHYSIK, Vol: 533, ISSN: 0003-3804- Author Web Link
- Cite
- Citations: 2
-
Journal articleCannon T, Lagarto J, Dyer B, et al., 2021,
Characterisation of NADH fluorescence properties under one-photon excitation with respect to temperature, pH and binding to lactate dehydrogenase
, Optical Society of America Continuum, Vol: 4, Pages: 1610-1625Reduced nicotinamide adenine dinucleotide (NADH) is the principal electron donor in glycolysis and oxidative metabolism and is thus recognized as a key biomarker for probing metabolic state. While the fluorescence characteristics of NADH have been investigated extensively, there are discrepancies in the published data due to diverse experimental conditions, instrumentation and microenvironmental parameters that can affect NADH fluorescence. Using a cuvette-based time-resolved spectrofluorimeter employing one-photon excitation at 375 nm, we characterized the fluorescence intensity, lifetime, spectral response, anisotropy and time-resolved anisotropy of NADH in aqueous solution under varying microenvironmental conditions, namely temperature, pH, and binding to lactate dehydrogenase (LDH). Our results demonstrate how temperature, pH, and binding partners each impact the fluorescence signature of NADH and highlight the complexity of the fluorescence data when different parameters produce competing effects. We hope that the data presented in this study will provide a reference for potential sources of variation in experiments measuring NADH fluorescence.
-
Journal articleMurray RT, Chandran AM, Battle RA, et al., 2021,
Seeded optical parametric generation in CdSiP2 pumped by a Raman fiber amplifier at 124 µm
, Optics Letters, Vol: 46, Pages: 2039-2039, ISSN: 0146-9592We report a seeded optical parametric generator (OPG) producing tunable radiation from 4.2–4.6 µm. The seeded OPG employs a 13 mm long CdSiP2 (CSP) crystal cut for non-critical phase-matching, pumped by a nanosecond-pulsed, MHz repetition rate Raman fiber amplifier system at 1.24 µm. A filtered, continuous-wave fiber supercontinuum source at 1.72 µm is used as the seed. The source generates up to 0.25 W of mid-infrared (MIR) idler power with a total pump conversion of 42% (combined signal and idler).
-
Journal articleKerridge-Johns WR, Jaillot J-B, Damzen MJ, 2021,
Sampling a vortex from a Gaussian beam using a wedge-plate shearing interferometer
, Applied Optics, Vol: 60, Pages: 3510-3510, ISSN: 1559-128XMany vortex-generation techniques have been developed to address a range of potential applications, exploiting their unique amplitude and phase profiles and their possession of orbital angular momentum. In this work, we present what may be the simplest method of vortex beam generation, requiring only a wedged optic: the wedge-plate shearing interferometer (WPSI). We show that the WPSI can reflect a first order Laguerre–Gaussian vortex beam (LG01) with a theoretical purity of >99% from an input fundamental Gaussian beam, with 98% LG01 purity experimentally demonstrated. We demonstrate 1% power conversion with a route to 14%. The monolithic WPSI is a simple, compact, and highly stable device, which can operate at any wavelength that the material is transparent to. We anticipate that it will be useful where sampling a robust, high-purity vortex beam from a Gaussian laser beam is required, including low-cost vortex generation for metrology or education.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.