Multimodal Shortwave Infrared Imaging for Visualization of Injection Laryngoplasty.

This study aims to explore two-dimensional semiconductor materials with superior carrier transport properties to meet the growing demands of high-speed electronics and optoelectronic devices, focusing on evaluating the feasibility of monolayer FeGa<sub>2</sub>S<sub>4</sub> as a candidate material through systematic theoretical investigations. First-principles calculations are used to analyze the exfoliation energy of FeGa<sub>2</sub>S<sub>4</sub> bulk crystal, as well as the structural stability, mechanical properties, and strain-dependent optoelectronic behavior of its monolayer counterpart. Strain engineering strategies, including uniaxial and biaxial strain, are used to assess carrier mobility modulation and spectral response. Our calculation results indicate that monolayer FeGa<sub>2</sub>S<sub>4</sub> is an indirect bandgap semiconductor (<i>E</i><sub>g</sub> = 1.65 eV) with low stiffness (Young’s modulus up to 151.6 GPa) and high flexibility (Poisson’s ratio less than 0.25), demonstrating exceptional thermodynamic stability. Under +5% uniaxial tensile strain, its electron mobilities along <i>x</i> and <i>y</i> directions dramatically increases to 5402.4 cm<sup>2</sup>·V<sup>–1</sup>·s<sup>–1</sup> and 4164.0 cm<sup>2</sup>·V<sup>–1</sup>·s<sup>–1</sup>, fivefold higher than its hole mobility. Biaxial strain outperforms uniaxial strain in bandgap modulation and induces a systematic redshift in optical spectra, significantly enhancing visible-light harvesting efficiency. This work reveals that monolayer FeGa<sub>2</sub>S<sub>4</sub> is a promising high-mobility photoactive material for next-generation solar cells and optoelectronics. The strain-mediated control of electronic and optical properties provides a theoretical framework for optimizing 2D semiconductors and critical guidance for experimental synthesis and device engineering. These findings highlight the potential of materials in advancing energy conversion technology and photonic applications.

The substitution reaction of Cl- ion in the complex [IrCl6]2- with the acetone molecule was investigated in detail by CW X-band EPR and UV-Vis spectroscopy methods. An original software package for deconvolution of a series of EPR or optical spectra has been developed. Based on the all-data analysis, the most probable mechanism of the process under study is proposed, including four reactions (two reversible ones). One of the stages is the redox reactions between iridium(IV) and iridium(III).

Detection and Identification of Multiple Soft Failures in Optical Networks Based on Hybrid Learning and Ultra-High-Resolution Optical Spectrum

Two novel π-extended BOPYIN cores and their derivatives (10a-10e) were prepared, exhibiting significant red-shifts vs. conventional BOPYINs and BODIPY derivatives in optical spectra. Notably, condensation product 5 and BOPYIN derivatives selectively converted to a six-membered BODIPY analogue (11). Furthermore, grinding can repeatedly light up the solid-state fluorescence of compound 7.

Nucleic acid and protein extraction, digestion, and purification are common steps of sample preparation and assays such as DNA sequencing, cell-viability, and enzyme activity in the modern biomedical laboratory. To increase the throughput of assays, microplates are often used to process many samples in parallel by a single operator. In this work, we have fabricated microplates that have an array of metallic elements integrated with them to form a metasurface, a periodic array of subwavelength metal scattering elements on a dielectric substrate, that are designed for the radio frequency (RF)/microwave region of the electromagnetic spectrum. By integrating the metasurface with a microplate, high-throughput processing without transferring samples becomes possible since the entire microplate can be irradiated with a RF/microwave radiation source and the metasurface will distribute electric field intensity and dielectric heating to the desired regions of the microplate, analogous to how plasmonic materials can guide and confine field intensities of visible and infrared frequency radiation. This analogue of plasmonic excitations and localization at lower frequencies in the RF/microwave region of the spectrum is termed spoof plasmonics due to its similarity to the plasmonic phenomena observed at visible frequencies. Using finite-difference time-domain (FDTD) modeling software, metasurfaces were designed for the RF/microwave frequency range and then fabricated using standard 96-well microplates and metallic films. The properties of the finished microplate system were characterized using a variety of physical and chemical methods including forward-looking infrared (FLIR) imaging, fluorescence sensing, and microbial inactivation and the system was then applied to a common polymerase chain reaction (PCR) assay to assess its real-world applicability. Herein we report our findings for various physical properties of the metasurface under a range of conditions as well as its application to biomedical laboratory assays and processing techniques. Our results demonstrate both a novel application of metasurfaces in bioprocessing and comparisons of in silico results with actual results for microwave metasurfaces.

Effects of lanthanum oxide concentrations on the optical parameters, magnetic spectra and radiation shielding efficiency of CoO–Na2O–B2O3 glass system

Synthesis, characterization and biological evaluation of a novel chalcone derivative: Spectroscopic, DFT, docking, ADMET and MD Studies.

<sec>To meet the growing demand for high-frequency broadband signal processing in complex electromagnetic environments and to overcome the limitations of traditional electronic systems such as restricted bandwidth, limited response speed, and low integration density, this paper presents a reconfigurable microwave photonic channelized receiver chip implemented on a silicon photonic platform. The proposed architecture adopts a two-stage optical filtering strategy that circumvents the typical strict wavelength alignment requirements in traditional designs, thereby greatly alleviating the challenges of system integration. In the first stage, the cascaded Mach-Zehnder interferometer (MZI)-based wavelength division multiplexers (WDMs) are used to perform Gaussian-shaped filtering of the input optical spectrum with a channel spacing of approximately 200 GHz. The second stage combines an array of coupled resonator optical waveguide (CROW) filters functioning as finely tunable bandpass elements. These CROW filters utilize curved waveguide directional couplers, which are specifically designed to address the issues found in traditional multimode interference (MMI) couplers such as high insertion loss—and in straight directional couplers, which encounter significant coupling dispersion. The optimized curved coupler exhibits an insertion loss below 0.03 dB and a coupling ratio variation of less than 10% across the 1500–1600 nm wavelength band. Filter bandwidth reconfigurability is achieved via thermo-optic tuning of the balanced MZI embedded within each CROW filter, enabling dynamic adjustment of the coupling coefficients. Each filter exhibits a continuously adjustable 3 dB bandwidth ranging from 2.25 GHz to 3.12 GHz, with an excellent 20 dB/3 dB shape factor of 3.08. This performance indicates significantly improved roll-off characteristics compared with the performance of traditional filter designs, leading to enhanced suppression of image frequency components and improved signal separation fidelity.</sec><sec>A complete microwave photon channelized receiving link is constructed using an integrated WDM-CROW filter bank. System-level simulations confirm that the architecture provides excellent broadband adaptability, supporting the channelization of radio frequency (RF) signals in two operational bands: 8–28 GHz and 8–36 GHz. The system efficiently decomposes the input wideband RF signal into eight independent intermediate frequency (IF) sub-bands. Within each sub-band, an image rejection ratio (IRR) exceeding 22 dB is maintained. The corresponding IF ranges are 1.4–3.6 GHz when configured for 8–28 GHz RF input, and 2–5 GHz for 8–36 GHz input, covering critical communication and detection bands from X-band to K-band and satisfying the requirements of multi-scenario signal processing. Furthermore, we simulate the reception and reconstruction of a 5 GHz bandwidth linear frequency-modulated (LFM) signal, successfully verifying the chip’s capability in handling wideband waveforms. These results underscore the feasibility of the proposed chip as a high-performance solution for advanced applications such as radar detection and broadband electronic warfare systems, offering a novel, integrated photonic alternative to traditional channelized reception architectures.</sec>

High-performance on-chip photodetectors are critical for next-generation integrated photonic systems that enable efficient sensing, optical communication, and light detection. Waveguide-integrated two-dimensional (2D) materials, among various material platforms, offer promising solutions for enhanced light-matter interactions due to their remarkable electrical and optical properties. In this article, we have simulated and experimentally demonstrated, for the first time, an ultracompact MoS2-based photodetector integrated with a coiled silicon nitride waveguide, which is designed to maximize the light-matter interaction by increasing the optical light absorption and improving the responsivity and external quantum efficiency. In contrast to the conventional straight waveguide integration with 2D materials, the coiled waveguide architecture with the MoS2 flake significantly extends the optical interaction length, which allows prolonged evanescent interaction with the MoS2 flake, resulting in an increase in responsivity of over 500% compared to a referenced straight waveguide structure. Our fabricated coiled structural photodetector achieves an excellent responsivity of 600 mAW-1, an external quantum efficiency of 145%, a normalized photocurrent-to-dark current ratio of 9.35 × 1014 AW-3, and a noise equivalent power of 1.72 × 10-9 W under optimal operating conditions. The coiled waveguide's performance confirms that this architecture maximizes optical absorption and photocurrent by extending the light-matter interaction length.

Objective. In the fight against cancer, improving the detectors performance is crucial to enhance diagnostic accuracy and optimize therapeutic monitoring. Current clinical SPECT systems predominantly rely on NaI(Tl) crystals, which, despite their advantages, suffer from limited count-rate performance due to long scintillation decay times. Our goal is to address this limitation by developing an innovative class of plastic scintillators doped with high-Z elements. These materials combine the fast timing characteristics of organic scintillators with improved gamma-ray detection efficiency via enhanced photoelectric interaction probability. Methods. Our research has focused on synthesizing novel organic fluorophores to fabricate plastic scintillators doped with high-Z elements with concentrations up to 10%. Moreover, we explored different fabrication techniques, including thermal polymerisation, photoinitiated polymerisation and resin 3D-printing. Results. The resulting prototypes show promising characteristics in terms of optical transparency, dopant homogeneity, light yield and timing performance, reaching levels comparable with commercial standards. Conclusions. These novel scintillators will be at the core of a next-generation SPECT detector, in which the doped scintillators are polymerized directly into the holes of a 3D-printed tungsten collimator, with signal readout performed by tiled CMOS sensors to fully exploit the plastics’ timing properties, and FPGA modules for data pre-processing. Moreover, they will serve for the development of a compact portable dosimeter tailored for metastatic castration-resistant prostate cancer (mCRPC) patients undergoing Lu-177-PSMA-617 radio-metabolic therapy. This device is designed to retrieve the radiopharmaceutical washout curve without requiring multiple SPECT scans, in order to customize the radiopharmaceutical prescription by determining the patient-specific radiometabolic parameters.

Insight into the transfer of energetic hot carriers (HCs) from plasmonic nanostructures to specific vibrational coordinates of adsorbed molecules is essential for understanding the HC-driven reaction mechanism, yet this process remains incompletely elucidated. Here, using 4-nitrothiophenol (4-NTP) adsorbed on gold nanoparticles (AuNPs) as a model system, we demonstrate that femtosecond visible pump-sum frequency generation vibrational spectroscopy (SFG-VS) probe technique can quantitatively monitor ultrafast interfacial HC injection into 4-NTP molecules following AuNP excitation, by detecting the third-order nonlinear SFG response (χ(3)) of specific vibrational modes. The HC transfer efficiencies from AuNPs to the NO2 coordinates are determined to be 45-55% and 21-23% for interband and intraband excitations, respectively, significantly higher than those to the C═C coordinates. A higher HC transfer efficiency is correlated with an enhanced reaction yield. The observed selectivity in HC transfer to specific vibrational coordinates highlights the dominance of nonthermal pathways in plasmonic catalysis.

Topaz is frequently subjected to heat treatment and irradiation to enhance colour, particularly to produce the market's most preferred salmon pink and sky blue varieties. However, an insufficient description of these processes can lead to fraudulent practices. This experimental and forensic mineralogical and gemmological study investigates eighteen heat-treated topaz samples from Ouro Preto (OP) and Caraí (CA), Brazil, using electron microanalysis, LA-ICP-MS, Raman, and optical absorption spectroscopy before and after heat treatment at various temperatures. The most significant optical changes were observed at 300°C when the CA sample lost its colour from sky blue to colourless, while OP samples retained their imperial orange colour up to 500°C before transitioning to pink at 700°C. Chemically, the CA samples are rich in F (> 1.8 apfu) with low trace element concentration (Fe ≤ 125 ppm, Ge ≤ 153 ppm), falling to the pegmatite and greisen field of topaz origin. The OP samples contain less F (1.4-1.5 apfu) but higher trace element contents (Cr up to 204 ppm, Ti up to 115 ppm, Fe, Mn, Ge < 64 ppm), consistent with a hydrothermal origin. Raman spectra show no significant inter-sample variation, but their luminescence spectra feature strong differences: Mn acts as the luminophore in CA samples, while Cr3+ centers dominate in OP samples. The optical absorption spectra reveal distinct thermal responses. The OP samples heated to temperatures ≥ 500°C developed new absorption bands at 530-532nm, consequently resulting in a visible pink colour. On the other hand, the CA spectra exhibit strong absorption in the NIR region; the unheated sample has a broad absorption band at 634nm, responsible for the sky-blue colour of topaz. Heating ≥ 300°C eliminates the transmission window in the blue to cyan regions, removing blue colouration. These thermal-optical signatures serve as indicators of heat treatment in topaz declared from these two localities. Moreover, the combination of spectroscopic methods, which we successfully applied in recognizing heat treatment on the studied samples, provides a systematic approach for identifying treatment in topaz and potentially other gemstones.

Abstract This study explores the efficacy of Solvent Vapor Annealing (SVA) in enhancing the performance of Organic Solar Cells (OSCs) by mitigating charge recombination and improving charge extraction, which are prevalent issues limiting their efficiency. Focusing on an OSC blend with known suboptimal characteristics, we specifically examine the effects of SVA on the blend's morphology, optical properties, and charge dynamics. Notably, SVA treatment significantly increases the short-circuit current density (JSC) from 17.29 ± 0.38 mA/cm² to 26.82 ± 0.79 mA/cm² for an optimal 30-second treatment. However, extended treatment durations inversely affect the JSC, indicating the need for precise control of the SVA protocol. The treatment also induces shifts in the optical absorption spectra and morphological changes. The impact of improved optical properties on charge photogeneration was analysed by Transfer Matrix Method (TMM) simulations, while transient absorption (TA), transient photovoltage (TPV) and transient photocurrent (TPC) measurements helped to understand the dynamics of charge recombination. Both features explain the increase in experimental cell performance. These findings bring light to the mechanisms behind the use of SVA to enhance OSC performance and underscore its potential by careful implementation of a simple post-processing technique.

Abstract Background Resection margins and lymph node status in upper gastrointestinal cancer surgery are crucial to postoperative outcomes, but their intraoperative assessment remains challenging. The current gold-standard, frozen section, is time-consuming, operator-dependent and limited to small sampling areas. Diffuse reflectance spectroscopy (DRS) is an optical technique that differentiates tissue by analysing the absorption and reflection of light within tissue. We investigated the performance of DRS in differentiating normal and malignant oesophageal, gastric and lymph node tissue ex- and in-vivo. Method Patients undergoing oesophagectomy or gastrectomy between May 2022 and November 2024 were recruited at Imperial College Healthcare NHS Trust, London. Optical spectra were collected ex-vivo from lymph nodes and in-vivo from normal and suspected tumour tissue in the stomach and oesophagus using a custom-built handheld sterilisable DRS probe. Spectra were correlated with histopathology for ground-truths labelling and used to train an XGB machine learning classifier for binary classification. Performance was evaluated for sensitivity, specificity and accuracy. Results 6,470 stomach and 3,116 oesophageal spectra were acquired from 32 patients in-vivo, and 12,685 spectra were acquired from 169 lymph nodes from 45 patients ex-vivo. For differentiating normal from cancer tissue, XGB achieved sensitivity, specificity and diagnostic accuracy as follows: stomach—77%, 95% and 90%; oesophagus—85%, 81% and 83%; and lymph nodes—90%, 98% and 96%. Conclusions DRS combined with real-time tracking and machine learning can accurately differentiate normal and malignant tissue in the oesophagus, stomach and lymph nodes. This supports its translational potential for integration in operating theatres to enhance surgical precision and improve cancer outcomes.

Background. One of the promising elements of optical and quantum communication systems is various delay lines built on the high-quality dielectric resonators (DRs). These lines typically comprise a substantial number of elements, making the optimisation of their parameters quite challenging. The theory of DRs serves as a foundation for comprehending, calculating, and optimising the parameters of delay lines and other devices, facilitating a considerable reduction in the computational resources that typically require the use of powerful computers. Objective. The study aims to derive analytical expressions for the electromagnetic parameters of diverse optical waveguides, composed of numerous types of DRs, to utilise them as transmission lines for optical communication systems. To address this issue, an infinite linear system of equations has been derived based on the perturbation theory applied to Maxwell's equations, which connects the complex amplitudes, wave numbers and the resonator frequencies. Methods. To derive solutions for the analytical expressions, perturbation theory and the theory of infinite linear equations are employed. The outcome is a set of new general analytical formulae that describe the dispersion curves of lattices made up of an infinite number of various types of DRs. Results. A theory of wave propagation in systems of interconnected one-, two-, and three-dimensional lattices of DRs extended infinitely in one or more directions has been developed. New analytical expressions for the dispersion characteristic of eigenwaves, delay times, and distributions of complex amplitudes of resonators, without any limitations on their quantity, have been derived. By utilising perturbation theory, a novel analytical model has been developed that describes the eigenwaves of three-dimensional lattices composed of identical ring structures of DRs. General analytical solutions for frequency dependencies and amplitudes for one-, two-, and three-dimensional lattices with varying arrangements of resonators have been identified. Conclusions. The developed theory serves as the foundation for the analysis and design of many devices operating within the optical wavelength spectrum, constructed upon an infinite variety of distinct types of DRs. The obtained new analytical expressions for calculating optical waveguide parameters, based on coupled oscillations of DRs, enable the development of innovative and more efficient mathematical models for various optical communication devices.

Thermophotovoltaic (TPV) systems offer a promising route to convert thermal radiation into electricity with high efficiency, particularly when waste heat or high-temperature sources are available. A key challenge in TPV system design is to match the optical spectrum of the source to the absorption spectrum of the photovoltaic (PV) cell. While spectral control can be achieved through engineered emitters or optical filters, the design of high-performance, multilayer filters is a complex optimization problem due to the large parameter space and fabrication constraints. Here, we introduce a deep reinforcement learning (DRL) framework to design multilayer optical filters that selectively transmit a narrowband of above-bandgap photons, while reflecting sub-bandgap and excessively high-energy photons back to the emitter. Our DRL-based approach integrates transfer matrix method simulations with a customized reward function and the detailed balance model to maximize the system's power conversion efficiency. We demonstrate filters that closely approximate ideal spectral profiles and predict TPV efficiencies exceeding 50% for silicon PV cells and emitter temperatures below 1500 °C. This method provides a scalable, data-driven pathway for designing advanced optical components in next-generation energy conversion systems.

Abstract We observed the isolated neutron star (NS) RX J2143.0+0654 with the Hubble Space Telescope (HST) in the UVOIR wavelength range (0.14–1.7 μ m). The UV part is consistent with a Rayleigh–Jeans tail of a thermal spectrum, f ν ∝ ν 2 , while a power-law spectrum, f ν ∝ ν α with α ∼ −0.8, dominates in the near-IR–optical. A joint fit of the UVOIR and contemporaneous X-ray spectra with a two-component blackbody with possible absorption features + power-law optical spectrum yields the following temperature and apparent radius of the colder component (which gives the main contribution in the UV): kT cold ≈ 45 eV and R cold ≈ 6 d 260 km, where d 260 is the distance in units of 260 pc. The temperature and radius of the hotter component, kT hot ≈ 106 eV and R hot ≈ 1.5 d 260 km; the parameters of an absorption feature at 0.74 keV; and the properties of X-ray pulsations are the same as found in previous X-ray observations. In the near-IR images, the NS is possibly surrounded by extended emission with a characteristic size of ∼2″ and flux densities of about 1.7 and 0.9 μ Jy at 1.54 and 1.15 μ m, respectively. Comparison with a previous HST observation in the optical 14 yr ago shows a proper motion μ ≈ 6 mas yr −1 , which corresponds to a small transverse velocity of 7 d 260 km s −1 . It is consistent with the hypothesis that the NS was born in the vicinity of the solar system about 0.5 Myr ago.

Abstract The Mn 2+ intoxicated Cd Cs 2 (SO 4 ) 2 ·6H 2 O (CCS) single crystals' splitting parameters of zero field are computed utilizing the superposition model. The determined parameters match well with those obtained from EPR. The inference of EPR experiment that in CCS, the Mn 2+ ion takes the position of the Cd 2+ site is verified by theoretical study. The crystal's optical spectra are found by utilizing the crystal field parameters evaluated from the superposition model and crystal field analysis program. A fair match between the calculated and experimental band positions is noted. Therefore, the experimental findings are confirmed by the theoretical calculations.

The results of the study “Improving the Efficiency of Solar Cells by Incorporating Advanced Nanomaterials” shows that incorporating nanomaterials into solar cells represents a major development towards increasing the efficiency of these cells. The main benefits of using nanomaterials include improving light absorption, reducing losses due to reflection, and increasing the overall efficiency of energy conversion. The study addresses several areas in which nanomaterials can contribute, such as the design of multi-layer solar cells (Tandem Solar Cells) that make better use of the solar spectrum, allowing them to exceed the traditional limit on solar cell efficiency. The study also addresses the importance of anti-reflection coatings and modifying the optical spectrum using these materials, which increases the quantity of light that is assimilated and transformed into electrical energy. The study considers that current challenges include the stability of nanomaterials and the possibility of large-scale manufacturing, but it remains optimistic about the future, with expectations of further improvements in efficiency as research and development in this field continue. This comprehensive overview of developments in the field of solar cells using nanomaterials reflects the future direction of making solar energy more effective and efficient.