Article
Engineering, Electrical & Electronic
Joohyung Song, Hyungjun Heo, Sangjun Lee, Sangin Kim
Summary: We propose a novel approach to achieve unidirectional radiation in an asymmetric single resonator without using an external mirror. Through the mutual coupling between two degenerate resonant modes, the resonator can mimic a one-port system. The design of such devices is straightforward with the use of temporal coupled-mode theory and practical design method derived from it. Numerical simulations demonstrate the effectiveness of the proposed approach, showing a high ratio between upward and downward radiations.
JOURNAL OF LIGHTWAVE TECHNOLOGY
(2022)
Article
Chemistry, Analytical
Fan-Ching Chien, Chun-Yu Lin, Gerald Abrigo
Summary: Surface plasmon-coupled emission (SPCE) substrates were fabricated to enhance the blinking fluorescence of spontaneously blinking fluorophores in single-molecule localization microscopy (SMLM), with the silver-layer substrate of 44 nm thickness producing the highest SPCE fluorescence and highly directional emission. This substrate improved detection efficiency, reduced fluorescence background, and allowed for precise localization of fluorophores, leading to a 480% fluorescence enhancement and reduced excitation power density for imaging EGFR distribution. Additionally, SPCE-SMLM imaging revealed a decrease in EGFR abundance at the plasma membranes of cells treated with PIKfyve-specific inhibitor.
ANALYTICAL CHEMISTRY
(2021)
Article
Optics
Samyobrata Mukherjee, Jordi Gomis-Bresco, David Artigas, Lluis Torner
Summary: This study demonstrates that anisotropic planar anti-guiding waveguide structures can support unidirectional guided resonances, where radiation is cancelled in one channel and redirected into another. The mechanism described allows for the easy selection of radiation direction, as well as tuning of wavelength and propagation angle for the UGRs to occur at specific wavelengths and light propagation directions.
Article
Thermodynamics
J. E. Avalos-Patino, S. Dargaville, S. J. Neethling, M. D. Piggott
Summary: The study examines the effects of an inhomogeneous unsteady participating media on combined convection-radiation in a rectangular enclosure, highlighting the importance of different gas modelling approaches. A new non-uniform discretisation method for the absorption distribution function is introduced to improve model performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Optics
Abdul-haseeb Munj, William R. Kerridge-Johns
Summary: In this work, a compact unidirectional Nd:YVO4 ring laser with an intracavity wedge-plate shearing interferometer (WPSI) as an output coupler was used to directly generate a high power and high purity LG01 optical vortex (OV). Compared to other designs, the monolithic WPSI offers advantages in stability and simplicity. The system is compact, cheap, and can be easily adapted to generate OV at wavelengths currently unobtainable using other methods.
Article
Multidisciplinary Sciences
Rashid A. Ganeev
Summary: This paper demonstrates methods for enhancing the strong high-order harmonics of femtosecond pulses in laser-induced plasma. By applying different techniques, the harmonic yield can be increased in various spectral ranges. These techniques have been shown to significantly increase the harmonic yield in indium plasma.
SCIENTIFIC REPORTS
(2023)
Article
Optics
Utpal Nundy
Summary: Theoretical model for a rotating mirror Q switched CW CO laser is presented, describing the laser process by calculating rate equations for 36 vibration levels, 397 rotational sublevels, and equations for photon densities associated with 360 lasing lines. The results show that multiple lasing lines operate in different vibration bands, but only a few lines are strong and can achieve time synchronization.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Engineering, Electrical & Electronic
Chieh-Chen Tsai, Yu-Lung Lo, Ching-Min Chang, Po-Ling Huang
Summary: A Mueller matrix polarimetry was used to extract the mean absorbance of an anisotropic turbid media. The experimental results showed a linear increase in mean absorbance with increasing ink concentration. The simulation using LighTools also successfully demonstrated the extraction of mean absorbance based on a new methodology.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2023)
Article
Optics
Yongcui Mi, Satyapal Mahade, Fredrik Sikstrom, Isabelle Choquet, Shrikant Joshi, Antonio Ancona
Summary: This study explores the customization of the fusion zone in laser welding by using a deformable mirror to shape the laser beam. The results show that the geometry of the melt pool can be modified by shaping the power density distribution of the laser beam. This has potential applications in improving process efficiency and reducing remelting in laser beam additive manufacturing.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Optics
Renlai Zhou, Shijie Chen, Qian Li, H. Y. Fu, K. Nakkeeran
Summary: The experiment demonstrated the generation of supercontinuum comb with different comb-teeth structures by controlling the pump power and waveplate orientation. The maximum output powers of dual SC combs were 21.95 mW and 3.75 mW, respectively. This technique can be used in broadband spectrometers and full-field 3D metrology applications.
OPTICS AND LASER TECHNOLOGY
(2022)
Article
Optics
Zilan Pan, Yin Xiao, Yonggui Cao, Lina Zhou, Wen Chen
Summary: In this paper, a new method is proposed to achieve high-fidelity and high-robustness free-space optical data transmission through highly dynamic and turbid water using dynamic scaling factors. Optical experiments demonstrate that the proposed scheme is robust against water-flow-induced turbulence and turbid water and enables high-fidelity optical information transmission at specific wavelengths.
Article
Chemistry, Multidisciplinary
Hao Hu, Xiao Lin, Dongjue Liu, Hongsheng Chen, Baile Zhang, Yu Luo
Summary: Cherenkov radiation plays a crucial role in high-energy and particle physics, but its limited photon yield hampers its applications in various fields. A general approach has been reported to enhance Cherenkov radiation by using dispersionless plasmons, which can achieve a radiation enhancement rate more than two orders of magnitude higher than conventional Cherenkov radiation over an ultrabroad frequency band.
Article
Multidisciplinary Sciences
Jae Won Choi, Yeon Jin Cho, Ji Young Ha, Seul Bi Lee, Seunghyun Lee, Young Hun Choi, Jung-Eun Cheon, Woo Sun Kim
Summary: Synthetic CECT generated from NCCT improves the depiction of mediastinal lymph nodes.
SCIENTIFIC REPORTS
(2021)
Article
Optics
Alan T. K. Godfrey, Deepak L. N. Kallepalli, Sabaa Rashid, Jesse Ratte, Chunmei Zhang, P. B. Corkum
Summary: This study presents a novel method for controlling blister formation in Laser-Induced Forward Transfer (LIFT) by using a thin metal film between two polymer films. The laser energy deposition is primarily in the metal layer, and blister expansion is driven by laser-induced spallation of the gold film.
Article
Optics
Zuogang Yang, Longjie Fang, Xicheng Zhang, Haoyi Zuo
Summary: An improved ant colony optimization algorithm has been developed to control a scattered light field through a turbid medium, with enhanced search ability and the ability to shape the scattered light field. Simulations and experiments have shown that the algorithm offers good optimization effect, rapid convergence, and strong anti-interference ability.
OPTICS AND LASERS IN ENGINEERING
(2021)
Article
Instruments & Instrumentation
Christopher Corden, Pavel Matousek, Claudia Conti, Ioan Notingher
Summary: The study investigated the use of time-gated and micro-spatially offset Raman spectroscopy for sub-surface molecular analysis in optically turbid samples. Multiplexed spectral detection allowed fast acquisition of signals for three-dimensional Raman mapping, demonstrating the potential for practical applications in various fields.
APPLIED SPECTROSCOPY
(2021)
Article
Instruments & Instrumentation
Luca Ciaffoni, Pavel Matousek, William Parker, Elin A. McCormack, Hugh Mortimer
Summary: This study presents a generic analytical model for comparing the detection performance of Raman spectrometers based on grating and spatial heterodyne designs. It shows that the SNR ratio between the two types of spectrometers can vary by two orders of magnitude, with spatial heterodyne spectrometers potentially competing with compact grating designs in delivering comparable detection performance in a much smaller footprint.
APPLIED SPECTROSCOPY
(2021)
Article
Chemistry, Analytical
Sara Mosca, Priyanka Dey, Marzieh Salimi, Benjamin Gardner, Francesca Palombo, Nick Stone, Pavel Matousek
Summary: The proposed method utilizes Spatially Offset Raman Spectroscopy (SORS) to estimate the reduced scattering coefficient (mu(s)') of turbid samples, with high accuracy achieved through calibration on a PTFE model sample. Knowledge of mu(s)' in the NIR range is valuable for optimizing SORS illumination and geometric configurations, providing in-depth information about SORS measurements, and benefiting various photon applications in fields such as biomedical, pharmaceutical, security, forensic, and cultural sciences.
ANALYTICAL CHEMISTRY
(2021)
Article
Chemistry, Analytical
Sara Mosca, Priyanka Dey, Marzieh Salimi, Benjamin Gardner, Francesca Palombo, Nick Stone, Pavel Matousek
Summary: This study investigates how SORS probes for specific depths in turbid samples, highlighting the reduced scattering coefficient of the medium as a key parameter in determining the probed zone. The proposed methodology was tested with experimental data, showing its relevance to a wide range of SORS applications and the importance of providing additional information for SORS measurements.
ANALYTICAL CHEMISTRY
(2021)
Article
Physics, Multidisciplinary
A. Botteon, M. Realini, C. Colombo, C. Conti, P. Matousek, C. Castiglioni
Summary: This study systematically investigates the micro-SORS capability to characterize a system where an agent diffuses into a turbid matrix, with potential applications in heritage science and other fields. The experiments show that the slope of the Raman intensity decay rate ratio can correlate with the penetration depth of the agent, providing a non-destructive analytical tool for monitoring conservation treatments and other applications involving agent penetration.
EUROPEAN PHYSICAL JOURNAL PLUS
(2021)
Article
Chemistry, Multidisciplinary
Mehrvash Varnasseri, Howbeer Muhamadali, Yun Xu, Paul I. C. Richardson, Nick Byrd, David Ellis, Pavel Matousek, Royston Goodacre
Summary: The study explored the use of Raman spectroscopy and SORS technology for the non-destructive detection of adulteration in extra virgin olive oil. Results demonstrated that these methods have significant potential for rapid and accurate analysis.
APPLIED SCIENCES-BASEL
(2021)
Article
Chemistry, Analytical
Alessandra Botteon, Wang-Hyo Kim, Chiara Colombo, Marco Realini, Chiara Castiglioni, Pavel Matousek, Byung-Man Kim, Tae-Hyuk Kwon, Claudia Conti
Summary: This study demonstrates the ability to monitor the dye depth profile within the light active layer of dye-sensitized solar cells using a non-destructive/non-invasive Raman method, micro-spatially offset Raman spectroscopy (micro-SORS). The results show that micro-SORS can accurately discriminate between homogeneous and inhomogeneous dye depth profiles, and its analysis is reliable compared to destructive time-of-flight secondary ion mass spectrometry measurements.
ANALYTICAL CHEMISTRY
(2022)
Article
Instruments & Instrumentation
Max Dooley, Thomas Paterson, Louise Dexter, Pavel Matousek, Hamid Dehghani, Ioan Notingher
Summary: Spatially offset Raman spectroscopy (SORS) is a powerful technique for subsurface molecular analysis of optically turbid samples. Numerical modeling and experimental validation have shown that offsetting the laser source and detector in opposite directions can significantly improve spectral contrast and signal to noise ratio.
APPLIED SPECTROSCOPY
(2022)
Article
Chemistry, Multidisciplinary
Marzieh Salimi, Sara Mosca, Benjamin Gardner, Francesca Palombo, Pavel Matousek, Nicholas Stone
Summary: The development of new effective cancer treatment methods, especially photothermal therapy using plasmonically resonant metallic nanoparticles, has garnered attention. However, the effectiveness of photothermal therapy can be limited by parameters such as pain sensation experienced by the patient. This review summarizes studies on pain management and enhancing the efficiency of photothermal therapy.
Article
Spectroscopy
Chiara Castiglioni, Alessandra Botteon, Claudia Conti, Matteo Tommasini, Pavel Matousek
Summary: This study introduces an analytical physical description of micro-spatially offset Raman spectroscopy (micro-SORS) experiments in turbid samples and highlights its use for studying the penetration depth of chemical species into a matrix. The study demonstrates the relationship between the Raman intensity ratio and the concentration profiles of the analytes using a physical model and Monte Carlo simulation. The obtained formulas provide insights for interpreting micro-SORS data and comparing different samples.
JOURNAL OF RAMAN SPECTROSCOPY
(2022)
Article
Biochemistry & Molecular Biology
Nai-Hao Yin, Anthony W. Parker, Pavel Matousek, Helen L. Birch
Summary: The purpose of this study is to determine if Raman spectroscopy can detect age-related changes in tendon matrix molecules. The study found that old age groups had significantly higher Raman intensities and fluorescence levels compared to young tendons. Principal component analysis was able to distinguish between different age groups and tendon types. There was also a significant correlation between Raman spectra and levels of advanced glycation end-product (AGE) collagen crosslinks. These findings provide a basis for quantifying age-related chemical modifications to tendon matrix molecules in intact tissue.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Instruments & Instrumentation
Sara Mosca, Kay Sowoidnich, Megha Mehta, William H. Skinner, Benjamin Gardner, Francesca Palombo, Nicholas Stone, Pavel Matousek
Summary: In this work, we propose an advanced CCD read-out combined with SERDS for fast acquisition rates in Raman spectroscopy. The incorporation of a periodic mask and a smaller shift of charge on the CCD allowed for a 10-fold increase in acquisition speed compared to previous designs. The 10 kHz system outperformed earlier variants in different situations, enabling accurate data acquisition from moving samples and under varying ambient light conditions. The high-speed instrument has potential applications in disease diagnosis, accurate data acquisition, and monitoring rapidly evolving Raman signals.
APPLIED SPECTROSCOPY
(2023)
Article
Instruments & Instrumentation
Kay Sowoidnich, Michael Towrie, Pavel Matousek
Summary: This paper presents a holistic approach to addressing the problems of fluorescence interference, sample heterogeneity, and laser-induced sample heating in Raman spectroscopy. Long wavelength shifted excitation Raman difference spectroscopy (SERDS) combined with wide-area illumination and sample rotation is successfully applied for the investigation of selected wood species. The results demonstrate that SERDS is effective in separating the Raman spectroscopic fingerprints of wood species from intense fluorescence interference, and sample rotation with wide-area illumination allows for representative SERDS spectra within a short time.
APPLIED SPECTROSCOPY
(2023)
Article
Chemistry, Analytical
Benjamin Gardner, Pavel Matousek, Nicholas Stone
Summary: The article introduces a method to correct self-attenuation artifacts in Raman spectroscopy in deep biological tissue analysis. The method successfully reduces Raman spectral intensity variances and distortions in specific peak ratios, with potential to improve detection limits and depth in clinical specimen analysis.
Review
Multidisciplinary Sciences
Sara Mosca, Claudia Conti, Nick Stone, Pavel Matousek
Summary: Spatially offset Raman spectroscopy (SORS) is a spectroscopic technique that allows for non-invasive chemical characterization of diffusely scattering materials. It has been widely applied in fields such as disease diagnosis, explosive detection, non-destructive analysis of pharmaceutical products and art objects, with potential future applications.
NATURE REVIEWS METHODS PRIMERS
(2021)
