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 articleAustin C, Shang W, Huang L, et al., 2025,
Collimated phase measuring deflectometry II: Re-design of the optical layout for high-curvature surfaces
, Optics and Lasers in Engineering, Vol: 194, ISSN: 0143-8166Collimated phase measuring deflectometry (CPMD) is an optical metrology technique developed to improve upon traditional phase measuring deflectometry (PMD). CPMD utilizes telecentric imaging and collimated structured light illumination to eliminate the height-slope ambiguity present in traditional PMD measurements. After the publication of the first CPMD paper, efforts began to optimize the optical layout of the CPMD system. The first proposed change, and the one detailed in this work, was to move the Fourier transform (FT) lens closer to the surface under test (SUT). Moving the FT lens closer to the SUT meant that for a given FT lens diameter, a larger range of surface slopes on the SUT could be measured. This change to the optical layout was not trivial and introduced at least two concerns that had to be addressed: telecentricity in the imaging path and possible ghost reflections from the re-located FT lens. In this work, we examine how these concerns were addressed and present results showing that the revised optical layout is capable of measurement results at least as good as the original CPMD optical layout. We also demonstrate the increased slope measuring range of the revised optical layout.
-
Journal articleBoland MA, Lightley JPE, Garcia E, et al., 2025,
Model‐free machine learning‐based 3D single molecule localisation microscopy
, Journal of Microscopy, Vol: 299, Pages: 77-87, ISSN: 0022-2720<jats:title>Abstract</jats:title><jats:p>Single molecule localisation microscopy (SMLM) can provide two‐dimensional super‐resolved image data from conventional fluorescence microscopes, while three dimensional (3D) SMLM usually involves a modification of the microscope, for example, to engineer a predictable axial variation in the point spread function. Here we demonstrate a 3D SMLM approach (we call <jats:italic>‘easyZloc'</jats:italic>) utilising a lightweight Convolutional Neural Network that is generally applicable, including with ‘standard’ (unmodified) fluorescence microscopes, and which we consider may be practically useful in a high throughput SMLM workflow. We demonstrate the reconstruction of nuclear pore complexes with comparable performance to previously reported methods but with a significant reduction in computational power and execution time. 3D reconstructions of the nuclear envelope and an actin sample over a larger axial range are also shown.</jats:p>
-
Journal articleKrawczyk B, Kudlinski A, Murray RT, et al., 2025,
Two-photon microscopy using picosecond pulses from four-wave mixing in a Yb-doped photonic crystal fiber
, Biomedical Optics Express, Vol: 16, Pages: 2327-2336Two-photon microscopy (TPM) enables deep tissue imaging but requires excitation pulses that have a large product of average and peak power, typically supplied by femtosecond solid-state lasers. However, these lasers are bulky, and femtosecond pulses require careful dispersion management to avoid pulse broadening, particularly when delivery fibers are used. Here we present a compact, fiber-based picosecond laser source operating at 790 nm for TPM using an ytterbium-doped photonic crystal fiber (Yb-doped PCF). The Yb-doped PCF simultaneously amplifies 1064 nm input pulses and efficiently converts them to 790 nm via four-wave mixing, generating pulses with a peak power of up to ∼3.8 kW. The source has a variable repetition rate (1.48 MHz–14.78 MHz), enabling the two-photon excitation fluorescence signal to be maximized in the presence of excitation saturation. We benchmark our picosecond laser source against a femtosecond Ti:Sapphire laser for TPM of stained Convallaria majalis samples and demonstrate comparable fluorescence signal when the two-photon excitation conditions are matched.
-
Journal articleZhu S, Chen W, Temel T, et al., 2025,
Broadband and efficient third-harmonic generation from black phosphorus–hybrid plasmonic metasurfaces in the mid-infrared
, Science Advances, Vol: 11Black phosphorus (BP), with a mid-infrared (MIR) bandgap of 0.34 eV, presents itself as a promising material for MIR nonlinear optical applications. We report the realization of MIR third-harmonic generation (THG) in both BP and BP-hybrid plasmonic metasurfaces (BPM). BP exhibits a high third-order nonlinear susceptibility (χ<sup>(</sup>3<sup>)</sup>) exceeding 10<sup>−18</sup> m<sup>2</sup>/V<sup>2</sup> in the MIR region with a maximum value of 1.55 × 10<sup>−17</sup> m<sup>2</sup>/V<sup>2</sup> at 5000 nm. The BP flake achieves a THG conversion efficiency of 1.4 × 10<sup>−5</sup>, surpassing that of other 2D materials by over one order of magnitude. To further enhance this nonlinear performance, a BPM is designed and fabricated to achieve a two-order-of-magnitude enhancement in THG, leading to a record conversion efficiency of 6.5 × 10<sup>−4</sup>, exceeding the performance of previously reported metasurfaces by more than one order of magnitude. These findings establish BP as a promising platform for next-generation MIR nonlinear optical devices.
-
Journal articleLiu H, Kumar S, Garcia E, et al., 2025,
PolSpec: polarisation‐based detection for versatile, cost‐effective rapid hyperspectral imaging
, Journal of Biophotonics, ISSN: 1864-063X“PolSpec” is a flexible, cost-effective approach for rapid (including single-shot) spectrally resolved imaging. While established approaches, e.g., using cascades of dichroic beamsplitters, diffractive image splitters, or mosaic filters, typically have pre-determined spectral detection bands with cost and experimental complexity scaling with the number of spectral channels, PolSpec uses polarisation optics to provide continuously varying transmission across a configurable spectral range to generate “spectral modulation vectors” that can represent specific spectral signatures with lower data volumes than full spectral profiles. It can be implemented with almost any detector. Here we demonstrate low-cost single-shot widefield PolSpec-based hyperspectral imaging using a polarisation-resolving camera.
-
Journal articleDe Vries M, Dent LG, Curry N, et al., 2025,
Geometric deep learning and multiple-instance learning for 3D cell-shape profiling.
, Cell Syst, Vol: 16The three-dimensional (3D) morphology of cells emerges from complex cellular and environmental interactions, serving as an indicator of cell state and function. In this study, we used deep learning to discover morphology representations and understand cell states. This study introduced MorphoMIL, a computational pipeline combining geometric deep learning and attention-based multiple-instance learning to profile 3D cell and nuclear shapes. We used 3D point-cloud input and captured morphological signatures at single-cell and population levels, accounting for phenotypic heterogeneity. We applied these methods to over 95,000 melanoma cells treated with clinically relevant and cytoskeleton-modulating chemical and genetic perturbations. The pipeline accurately predicted drug perturbations and cell states. Our framework revealed subtle morphological changes associated with perturbations, key shapes correlating with signaling activity, and interpretable insights into cell-state heterogeneity. MorphoMIL demonstrated superior performance and generalized across diverse datasets, paving the way for scalable, high-throughput morphological profiling in drug discovery. A record of this paper's transparent peer review process is included in the supplemental information.
-
Journal articleJiang X, Damzen MJ, 2025,
Pump-induced lensing in Nd:YVO4 using transient wavefront measurements
, Optics Express, Vol: 33, Pages: 11972-11984Understanding pump-induced lensing in laser amplifiers is important for power scaling of solid-state lasers with maintenance of high beam quality, however, there is still incomplete knowledge of the relative role of different lensing processes, particularly between thermally-induced lensing and excited-state population-induced lensing. In this study, we directly measure the transient dioptric lensing in the diode-pumped neodymium-doped yttrium vanadate (Nd:YVO<inf>4</inf>) gain medium using a time-gated wavefront sensor. Pulsed pump-probe measurements of the transient growth and decay of pump-induced lensing clearly distinguish thermal and population lensing mechanisms by their different time signatures. Comparison of experimental transient pump-induced lensing results to analytical theory provides quantitative information on the absolute and relative thermal and population contributions to the amplifier lens under both lasing and non-lasing conditions. Observation of Nd:YVO<inf>4</inf> samples with different doping concentrations indicates higher heating in higher-doped sample due to increased energy transfer upconversion (ETU) leading to higher thermal lensing. From the measured population-induced lens and comparison to theory, quantitative estimate is made of the difference in polarizability of the excited and ground state in the Nd:YVO<inf>4</inf> ∆α<inf>p</inf> ≈ 7.7 10<sup>−32</sup> m<sup>3</sup>
-
Journal articleLiu H, Kumar S, Garcia Castano E, et al., 2025,
Open-source implementation of polarisation-resolved single-shot differential phase contrast microscopy (pDPC) on a modular openFrame-based microscope
, HardwareX, Vol: 21, ISSN: 2468-0672We recently demonstrated polarisation differential phase contrast microscopy (pDPC) as a robust, low-cost single-shot implementation of (semi)quantitative phase imaging based on differential phase microscopy. pDPC utilises a polarisation-sensitive camera to simultaneously acquire four obliquely transilluminated images from which phase images mapping spatial variation of optical path difference can be calculated. pDPC microscopy can be implemented on existing or bespoke microscopes and can utilise radiation at a wide range of visible to near infrared wavelengths and so is straightforward to integrate with fluorescence microscopy. Here we present a low-cost open-source pDPC module that is designed for use with the modular open-source microscope stand “openFrame”. With improved hardware and software, this new pDPC implementation provides a real-time readout of phase across a field of view that facilitates optimisation of system alignment. We also provide protocols for background subtraction and correction of crosstalk
-
Journal articleTageldeen MK, de Pooter GJ, Sardini A, et al., 2025,
Compact modular open platform for low-cost ultrasound imaging: Realisation and measurements in biological settings
, Measurement Journal of the International Measurement Confederation, Vol: 244, ISSN: 0263-2241Ultrasound Open-Platforms (OPs) offer the flexibility required for developing novel ultrasound techniques but are generally bulky and expensive, impeding deployment in primary care and low-resource settings. This paper introduces a modular OP to address these challenges by enabling trade-offs in size and cost to meet performance targets. Comprising five modules, the proposed OP integrates a digital back-end controller tailored for ultrasound imaging. Key features of the OP include generating arbitrary waveforms with a 20-MHz maximum frequency and ±100 V amplitude, precise delays with a 200-ps maximum error, programmable gain (12-dB to 51-dB), and a 12-bit ADC with a conversion rate of 100-MSPS. The OP modular structure enables performance scalability through extension modules. In-vivo experiments, including imaging E12 mouse embryos and rabbit aorta, demonstrate that the OP yields high-quality images and enables the detection of anatomical structures in small animals at a fraction of the cost and size of commercially available OPs.
-
Journal articleZhang M, Li R, Fu S, et al., 2025,
Deep learning enhanced light sheet fluorescence microscopy for in vivo 4D imaging of zebrafish heart beating.
, Light Sci Appl, Vol: 14Time-resolved volumetric fluorescence imaging over an extended duration with high spatial/temporal resolution is a key driving force in biomedical research for investigating spatial-temporal dynamics at organism-level systems, yet it remains a major challenge due to the trade-off among imaging speed, light exposure, illumination power, and image quality. Here, we present a deep-learning enhanced light sheet fluorescence microscopy (LSFM) approach that addresses the restoration of rapid volumetric time-lapse imaging with less than 0.03% light exposure and 3.3% acquisition time compared to a typical standard acquisition. We demonstrate that the convolutional neural network (CNN)-transformer network developed here, namely U-net integrated transformer (UI-Trans), successfully achieves the mitigation of complex noise-scattering-coupled degradation and outperforms state-of-the-art deep learning networks, due to its capability of faithfully learning fine details while comprehending complex global features. With the fast generation of appropriate training data via flexible switching between confocal line-scanning LSFM (LS-LSFM) and conventional LSFM, this method achieves a three- to five-fold signal-to-noise ratio (SNR) improvement and ~1.8 times contrast improvement in ex vivo zebrafish heart imaging and long-term in vivo 4D (3D morphology + time) imaging of heartbeat dynamics at different developmental stages with ultra-economical acquisitions in terms of light dosage and acquisition time.
-
Journal articleDas S, Temel T, Spindler G, et al., 2025,
Power scaling of a non-resonant optical parametric oscillator based on periodically poled LiNbO3 with spectral narrowing
, Optics Express, Vol: 33, Pages: 5662-5669Using a Volume-Bragg-Grating at the signal wavelength in a periodically-poled LiNbO<inf>3</inf> non-resonant optical parametric oscillator we achieve a total average power of 11.35 W at 20 kHz corresponding to a conversion efficiency of 63%. The measured signal and idler bandwidths amount to 0.7 and 0.9 nm at ∼1922 and ∼2384 nm, respectively. The spectral features are well reproduced by numerical modeling in the plane-wave approximation taking into account pump depletion and back conversion.
-
Thesis dissertationLerendegui M, 2025,
Simulation Framework of Contrast Enhanced Ultrasound (CEUS) and Microvascular Flow for Ultrasound Localization Microscopy (ULM) and Deep Learning
Standard ultrasound imaging is a widely adopted noninvasive and safe modality, known for its affordability, real-time imaging capabilities, and ease of use. Despite its advantages, it faces limitations such as low resolution due to the diffraction limit, and the need for high frequencies to increase resolution and visualize blood flow, that leads to a trade-off between frequency and depth.Recent decades have witnessed notable advancements in ultrasound vascular imaging, including the use of Microbubble (MB) contrast agents that highlight the vasculature --known as Contrast Enhanced Ultrasound (CEUS)--, and unfocused transmission techniques that significantly increase framerate. But more importantly, inspired by optical imaging techniques like STochastic Optical Reconstruction Microscopy (STORM) and Fluorescence Photo-Activated Localization Microscopy (FPALM), Ultrasound Localization Microscopy (ULM) emerged as a novel approach capable of overcoming the diffraction limit. ULM provides unprecedented in-vivo resolution for microvascular flow, producing super-resolved maps with detailed flow information.While the field of ULM has rapidly expanded, significant challenges for clinical translation exist, such as its low acquisition rate, and the need for algorithms capable of isolating, localizing and tracking MBs accurately.Many algorithms addressing these challenges were developed, but their performance has not been consistently evaluated and benchmarked. Some attempts of evaluation have been performed, but they all present some limitations such as using datasets without considering MB oscillation physics or focusing only on localization and not tracking.Additionally, the generation of datasets with known ground truth information is crucial for training deep learning models, as it provides a reliable reference for the network to learn from.For supervised learning in ULM, relying only on real world data is not an option due to the impossibility of obtaining ground truth l
-
Book chapterMcCall M, Koufidis S, 2025,
Static Bragg-Less and Dynamic Bragg-Like Resonances
, More Adventures in Contemporary Electromagnetic Theory, Editors: Chiadini, Fiumara, Publisher: Springer Nature Switzerland, Pages: 329-360Reflection and transmission of electromagnetic waves from one-dimensional periodic index perturbations (aka Bragg gratings) have, for many decades, been described very successfully using coupled-wave theory. We review some very recent theoretical developments that have led to new insights and predictions for the coupled-wave description of Bragg scattering in various complex photonic mediums. The key insight is that standard coupled-wave equations in two complex amplitudes describing propagation through a scalar Bragg grating may be reduced, via a Möbius transformation, to a single first-order differential equation of a real variable, one that readily exposes the underlying system symmetries and connects directly with the theory of coupled oscillators. Remarkably, the method can be extended to describe Bragg gratings in mediums of significant complexity, such as mediums with chiral magneto-electric coupling, which are additionally either structurally chiral or linearly birefringent. Regarding the former, we demonstrate how, for extreme values of chirality, a medium of a particular handedness can back scatter light of both circular states. For the latter, combining linear and circular birefringence gives rise to a circular Bragg-like response that is unexpectedly predicted to occur in a homogeneous medium. Off-axis propagation is also shown to lead to singular values of the supported refractive indices. Our techniques are also shown to be applicable to the currently topical theme of uniform mediums whose constitutive parameters are modulated in time. Such “temporal” Bragg gratings, particularly those exhibiting parametric amplification, give rise to nontrivial temporal modulation scenarios, accessible via our Möbius method. We conclude by highlighting the simultaneous polarization manipulation and amplification of lightwave signals that fall into momentum gaps formed in Brillouin space by time-periodic bi-isotropic mediums.
-
Conference paperKrawczyk B, Kudlinski A, Battle RA, et al., 2025,
Enhanced four-wave mixing in the normal dispersion regime of a Yb-doped photonic crystal fiber
, ISSN: 0277-786XWe present a novel photonic crystal fiber (PCF) optimized for degenerate four-wave mixing (FWM) in the normal dispersion regime, featuring a Yb-doped core to amplify the FWM pump light via stimulated emission. A 1064 nm fiber master oscillator power amplifier (MOPA) system was used as the FWM pump to generate anti-Stokes light at 790 nm. The anti-Stokes generation was enhanced by using a 976 nm continuous-wave laser diode to create a population inversion in the Yb-doped core, amplifying the 1064 nm pulses during their conversion to the anti-Stokes sideband. The 1064 nm fibre MOPA system has a pulse duration of 15 ps and includes a pulse picker to enable the repetition rate to be varied. To establish a baseline, FWM experiments were first conducted using an undoped PCF and then compared with the Yb-doped PCF. We observed significantly stronger anti-Stokes generation in the Yb-doped PCF at every repetition rate tested in the range 16.25–1.62 MHz. These results demonstrate that amplifying the FWM pump pulses through stimulated emission substantially enhances the anti-Stokes output power, offering a promising approach to improving pump-to-anti-Stokes conversion efficiency beyond the limits of non-rare-earth-doped FWM PCFs.
-
Journal articleAaron JS, Jacobs CA, Malacrida L, et al., 2025,
Challenges of microscopy technology dissemination to resource-constrained communities
, Nature Methods, ISSN: 1548-7091Discussions at a recent conference on microscopy technology dissemination spotlighted the importance of setting technology adoption capable of producing scientific outcome as the end goal. This Comment examines current global efforts in microscopy dissemination and summarizes the challenges and paths forward.
-
Journal articleTemel T, Zhu S, Chen W, et al., 2025,
Strong Mid-Infrared Optical Harmonic Processes Mediated by Excitons in Layered Indium Selenide
, Laser and Photonics Reviews, ISSN: 1863-8880Nonlinear optics in 2D materials has attracted significant attention due to their potential in various optoelectronic applications such as nonlinear optical detection, bioimaging, and nonlinear optical modulation. Optimising the nonlinear optical response in the infrared, especially the mid-infrared (MIR) region, is particularly desirable for various applications including tunable coherent sources, high-order harmonic generation, supercontinuum light generation, and frequency-comb-based spectroscopy. However, reports on MIR nonlinear optical responses in 2D materials are limited due to a lack of materials with suitable nonlinear optical properties. Van der Waals layered γ-phase indium selenide (γ-InSe) featuring broken inversion symmetry can serve as a promising candidate for MIR nonlinear devices. Beyond the noncentrosymmetric crystal structure, γ-InSe possesses unique out-of-plane dipoles, distinguishing it from other 2D materials such as black phosphorus (BP) and transition metal dichalcogenides (TMDs). Herein, multiphoton harmonic generation processes including second (SHG), third (THG), fourth (FHG) and fifth (FIHG) harmonic generation are investigated in γ-InSe in the MIR region. Notably, γ- InSe shows strong second and higher order nonlinearities. A metal-insulator-metal (MIM) plasmonic metasurface is further designed with large SHG and THG enhancement factors reaching 8400 and 32000 times, respectively. These results demonstrate the great potential of γ-InSe for next-generation MIR nonlinear photonic devices.
-
Journal articleBaldini F, Dholakia K, French P, et al., 2025,
Shining a Light on the Future of Biophotonics
, Journal of Biophotonics, ISSN: 1864-063XBiophotonics—the interdisciplinary fusion of light-based technologies with biology and medicine—is rapidly transforming research, diagnostics, and therapy across various domains. This white paper, developed in conjunction with the International Congress on Biophotonics 2024, offers a comprehensive overview of the current landscape and future potential of biophotonics. It discusses core technologies such as bioimaging, biosensing, and photonic-based therapies, while highlighting novel applications in oncology, infectious diseases, neurology, cardiovascular health, agriculture, food safety, and environmental monitoring. The document also explores key enablers, including artificial intelligence, novel materials, and quantum biophotonics, along with critical challenges related to standardization, regulation, and clinical translation. A SWOT analysis and recommendations are provided to guide future research, commercialization, and interdisciplinary collaboration, underscoring biophotonics as a cornerstone of next-generation precision medicine and the One Health approach.
-
Journal articleKoufidis SF, Koutserimpas TT, Monticone F, et al., 2024,
Electromagnetic wave propagation in time-periodic chiral media
, OPTICAL MATERIALS EXPRESS, Vol: 14, Pages: 3006-3029, ISSN: 2159-3930 -
Journal articleTan Q, Riemer K, Hansen-Shearer J, et al., 2024,
Transcutaneous imaging of rabbit kidney using 3-D acoustic wave sparsely activated localization microscopy with a row-column-addressed array
, IEEE Transactions on Biomedical Engineering, Vol: 71, Pages: 3446-3456, ISSN: 0018-9294Objective: Super-resolution ultrasound (SRUS) imaging through localizing and tracking microbubbles, also known as ultrasound localization microscopy (ULM), can produce sub-diffraction resolution images of micro-vessels. We have recently demonstrated 3-D selective SRUS with a matrix array and phase change contrast agents (PCCAs). However, this method is limited to a small field of view (FOV) and by the complex hardware required. Method: This study proposed 3-D acoustic wave sparsely activated localization microscopy (AWSALM) using PCCAs and a 128+128 row-column-addressed (RCA) array, which offers ultrafast acquisition with over 6 times larger FOV and 4 times reduction in hardware complexity than a 1024-element matrix array. We first validated this method on an in-vitro microflow phantom and subsequently demonstrated non-invasively on a rabbit kidney in-vivo. Results: Our results show that 3-D AWSALM images of the phantom covering a 25×25×40 mm 3 volume can be generated under 5 seconds with an 8 times resolution improvement over the system point spread function. The full volume of the rabbit kidney can be covered to generate 3-D microvascular structure, flow speed and direction super-resolution maps under 15 seconds, combining the large FOV of RCA with the high resolution of SRUS. Additionally, 3-D AWSALM is selective and can visualize the microvasculature within the activation volume and downstream vessels in isolation. Sub-sets of the kidney microvasculature can be imaged through selective activation of PCCAs. Conclusion: Our study demonstrates large FOV 3-D AWSALM using an RCA probe. Significance: 3-D AWSALM offers an unique in-vivo imaging tool for fast, selective and large FOV vascular flow mapping.
-
Journal articleKoufidis SF, Lakhtakia A, Mccall MW, 2024,
Comment on 'No circular birefringence exists in a chiral medium: an analysis of single-mode refraction'
, NEW JOURNAL OF PHYSICS, Vol: 26, ISSN: 1367-2630 -
Journal articleBharadwaj A, Kumar A, Kalita R, et al., 2024,
Super-resolved fluorescence imaging utilising accessible stochastic optical reconstruction microscopy (easySTORM) implemented on a low-cost, modular open-source (openFrame) microscope
, Measurement Science and Technology, Vol: 35, ISSN: 0957-0233Optical super-resolution microscope is a powerful tool for the life sciences, including cell biology and pathology yielding information on, e.g. biological structure and protein distribution in the nano-scale range. In recent years, there has been an exponential rise in the interest to apply super-resolution microscopes in diverse areas, but its wider utility is hindered by the cost of purchasing and maintaining super-resolved microscopes. In this paper we present the implementation of easySTORM, an accessible implementation of stochastic optical reconstruction microscopy (STORM) at Indian Institute of Technology Guwahati (IITG), India, in a flexible, user friendly and cost-effective manner using a state-of-the-art, modular, open-source, optical microscope platform called: 'openFrame'. Providing comparable imaging performance to commercial optical super-resolution microscopes, the openFrame-based implementation of easySTORM uses in-expensive multimode diode lasers and industry grade CMOS cameras, and the open-source and modular nature of the instrument makes it easy to maintain and to upgrade. To demonstrate its successful implementation at IITG, we image quantum dots and actin-tubulin structure in both normal and cancer cells, resolved features separated by a few tens of nanometers. This work demonstrates that openFrame-enabled easySTORM instrumentation can be widely accessible to provide affordable, research grade super-resolution microscopy capability for academic and medical research.
-
Journal articleXiao H, Damzen MJ, 2024,
High-efficiency 5-watt wavelength-tunable UV output from an Alexandrite laser
, APPLIED PHYSICS B-LASERS AND OPTICS, Vol: 130, ISSN: 0946-2171 -
Journal articleDe Corte A, Koufidis SF, Mccall MW, et al., 2024,
Exceptional points in negatively refracting chirowaveguides due to giant chirality
, PHYSICAL REVIEW A, Vol: 110, ISSN: 2469-9926 -
Conference paperXiao H, Damzen MJ, 2024,
5-Watt level widely wavelength-tunable UV output from a frequency-doubled Alexandrite laser
, ISSN: 2101-6275We demonstrate a record 5-Watt level, wavelength tunable, continuous-wave UV output based on a diode-pumped Alexandrite laser employing intra-cavity second harmonic generation. A wide wavelength tuning range from 364nm to 402nm was achieved.
-
Conference paperDamzen MJ, 2024,
Alexandrite Lasers: Review of recent laser progress and developments for vegetation lidar
, ISSN: 2101-6275A review is made of recent progress in diode-pumped Alexandrite lasers as a high-power, tunable-wavelength source, and our advances in developing Alexandrite as a short-pulse, high-pulse-rate vegetation lidar source for satellite-based Earth Observation.
-
Conference paperJiang X, Xiao H, Damzen MJ, 2024,
Transient Analysis of Pump-induced Lensing Effects in Alexandrite Lasers Using Pump-Probe Technique
, ISSN: 2101-6275A novel transient pump-probe method is used to differentiate thermal and population pump-induced lensing mechanisms. In diode-pumped Alexandrite lasers, excellent agreement is found between theory and experiment and the population lens is found to be dominant in non-lasing amplifier.
-
Journal articleBoland MA, Lightley JPE, Garcia E, et al., 2024,
Model-free machine learning-based 3D single molecule localisation microscopy
, Journal of Microscopy, ISSN: 0022-2720<jats:title>Abstract</jats:title><jats:p>Single molecule localisation microscopy (SMLM) can provide two-dimensional super-resolved image data from conventional fluorescence microscopes, while three dimensional (3D) SMLM usually involves a modification of the microscope, e.g. to engineer a predictable axial variation in the point spread function. Here we demonstrate a 3D SMLM approach (we call<jats:italic>“easyZloc”</jats:italic>) utilising a lightweight Convolutional Neural Network that is generally applicable, including with “standard” (unmodified) fluorescence microscopes, and which we consider may be practically useful in a high throughput SMLM workflow. We demonstrate the reconstruction of nuclear pore complexes with comparable performance to previously reported methods but with a significant reduction in computational power and execution time. 3D reconstructions of the nuclear envelope and a tubulin sample over a larger axial range are also shown.</jats:p>
-
Journal articleKoufidis SF, Koutserimpas TT, Monticone F, et al., 2024,
Enhanced scattering from an almost-periodic optical temporal slab
, PHYSICAL REVIEW A, Vol: 110, ISSN: 2469-9926 -
Conference paperKoufidis SF, Koutserimpas TT, Monticone F, et al., 2024,
Time-Periodic Optical Activity
, 2024 Eighteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials), Publisher: IEEE, Pages: 1-3 -
Conference paperDe Corte A, Koufidis SF, McCall MW, et al., 2024,
Exceptional Points of Degeneracy in Coupled Chirowaveguides
, 2024 Eighteenth International Congress on Artificial Materials for Novel Wave Phenomena (Metamaterials), Publisher: IEEE, Pages: 1-3
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.