2023 April - 136 articles
A novel slow-wave waveguide structure is proposed, the guided-wave properties of which can be controlled by the rotation of nonuniform metasurface elements loaded on the surface of the substrate-integrated waveguide. The proposed nonuniform metasurfa...
For several years, Fourier transform infrared (FTIR) microspectroscopy has been proving to be very promising for use in cytological diagnostics because of its capability of providing rapid and label-free biochemical information about cell samples. Th...
In this paper, an all-fiber laser feedback interferometer (LFI) with a diffraction grating was developed for sequential measurement of in-plane and out-of-plane displacements without changing the optical arrangement. When the light emitted from an er...
In this work, we fabricated the antireflection microstructures (ARMs) on ZnSe surfaces using a femtosecond Bessel direct laser writing in burst mode. The morphology and transmittance performance of ARMs with different single-pulse energies (from 200...
A mid-infrared difference frequency generator (DFG) based on a periodically poled thin-film lithium niobate rib waveguide on a sapphire substrate is theoretically studied. A mode analysis is carried out at the mid-infrared region, and the analysis fo...
This study explored the impact of atmospheric turbulence on partially coherent light propagation. Atmospheric turbulence causes random modulation of the intensity and phase of light, resulting in a speckle pattern in the far field. This study focused...
Particle-dispersed coatings emerged as a promising approach to regulate the apparent radiative properties of underlying substrates in various applications, including but not limited to radiative cooling, thermal management, and infrared stealth. Howe...
Open-path Fourier Transform infrared spectroscopy (OP-FTIR) is widely used in polluted gas monitoring. The spectral resolution, as a key parameter of FTIR detection technology, affects the quantitative analysis of gas concentration. In OP-FTIR, the n...
We report an experimental study of the effect of the temperature of the VCSEL on the probability of excitation of a linearly polarized mode when gain-switching the device. We consider different modulation frequencies and amplitudes. We show that the...
In this study, a dual−core D-shaped photonic crystal fiber (PCF) surface plasmon resonance sensor coated with gold grating is designed and analyzed using the finite-element method (FEM). The surface plasmon resonance (SPR) effect between the fi...
In this work, a prior-training-free and low-complexity modulation format identification (MFI) scheme, based on amplitude histogram distributions, was proposed and demonstrated, both numerically and experimentally, for autonomous digital coherent rece...
We theoretically analyzed the detailed carrier transport process based on the drift-diffusion model in the InGaAs/InP modified Uni-Traveling-Carrier Photodiode (MUTC-PD) under high optical input power conditions. A high-speed MUTC-PD design was simul...
In this paper, we introduce how gallium nitride-based (GaN-based) VCSELs with curved mirrors have evolved. The discussion starts with reviewing the fundamentals of VCSELs and GaN-based materials and then introducing the curved-mirror cavity’s p...
Fork-shaped gratings are periodic structures containing a spatial dislocation known to be used for the production of optical vortices in a far field. Spatial overlapping of diffraction orders in a near field results in complex spatial evolution of op...
Optical coherence tomography (OCT) has attracted attention in dermatology applications for skin disease characterization and diagnosis because it provides high-resolution (<10 μm) of tissue non-invasively with high imaging speed (2–8 s)....
This study aims to apply the densitometry distribution analysis (DDA) method to study corneal densitometry depending on age and corneal region from Galilei Dual Scheimpflug Analyzer tomography. A total of 83 healthy participants aged 39.02 ± 1...
Two-photon absorption has been systematically studied in Ca3(VO4)2 and Ca2.7Sr0.3(VO4)2 crystals, both of which are prospective nonlinear optical and laser host materials. A strong dependence of the two-photon absorption coefficients on the orientati...
The paper presents the results of theoretical and experimental studies of all-glass leakage channel microstructured optical fibers (MOFs) with a large mode area and low bending losses. These MOFs contain two layers of fluorine-doped silica glass elem...
Ultraviolet radiation (UVR) is generally considered a primary tumorigenic agent. While UVR exposure has been studied, especially at the skin level, the impact of UV exposure on internal tissues and its effect on the appearance and the development of...
We have conducted a study on a very-low-frequency acoustic-velocity sensor which is based on a cantilever of distributed-feedback (DFB) fiber laser immersed in castor oil. A mathematical model of the frequency dependent response of the proposed senso...
Free-space optical (FSO) communications can offer high-capacity transmission owing to the properties of the laser beams. However, performance degradation caused by atmospheric turbulence is an urgent issue. Recently, the application of polar codes, w...
In this paper, partially coherent radially polarized (RP) Laguerre-Gaussian (LG) rotationally symmetrical power-exponent phase vortex (RSPEPV) beams with the LG-correlated Schell-model (LGSM) were introduced. The statistical properties of the tightly...
Optical coherence tomography (OCT) attenuation imaging is a technique that uses the optical attenuation coefficient (OAC) to distinguish the types or pathological states of tissues and has been increasingly used in basic research and clinical diagnos...
Deep learning has better detection efficiency than typical methods in photoelectric target detection. However, classical CNNs on GPU frameworks consume too much computing power and memory resources. We propose a multi-stream inference-optimized Tenso...
Zero-field optically pumped magnetometers operating in the spin-exchange relaxation-free (SERF) regime have been extensively studied, and usually depend on zeroth-order parametric resonance to measure the magnetic field. However, the studies conducte...
This paper proposes a single-photon-counting lidar based on time coding that can obtain the target’s spatial location and measure the distance and azimuth angle in real time without needing a scanning device. Multiple optical fibers were used t...
Solution-processed devices with thermally activated delayed fluorescence (TADF) compounds have gained great attention due to their low cost and high performance. Here, two solution-processable TADF emitters named ACCz-DPyM and POxCz-DPyM were synthes...
In this work, a vertical N-I-P germanium (Ge) photodetector (PD) with a multi-mode waveguide input is presented. The fabricated devices exhibit a low dark current of 10 nA at bias of −1 V, and a high responsivity of exceeding 0.75 A/W over the...
In this paper, the stabilization and high efficiency of an unstable Second Harmonic Generation (SHG) of an
The development of integrated optical technology and the continuous emergence of various low-loss optical waveguide materials have promoted the development of low-cost, size, weight, and power optical gyroscopes. However, the losses in conventional o...
Given the relationship between spherical aberrations and accommodation, the study of these aberrations can be helpful to understand accommodative response in subjects with accommodative dysfunctions. The purpose of this study was to evaluate on-axis...
High-capacity, long-distance underwater wireless optical communication (UWOC) technology is an important component in building fast, flexible underwater sensing networks. Underwater communication with light as a carrier has a large communication capa...
Sideways THz generation in Mg:LiNbO3 crystal is studied considering Si-prism-lens couplers with different output surface curvatures. A theoretical approach is developed for modeling the angular distributions of THz radiation power inside the crystal,...
Transmission spectra of a symmetric microresonator structure, with dielectric Bragg mirrors, are obtained. The working cavity of the structure is partially filled by a layer of a quarter-wave thickness of finely layered “graphene–semicond...
This article presents the particle capture performance of annular slits, which offer a simple alternative to complex micro/nano structures used to excite and focus surface plasmon polaritons (SPPs). Additionally, the annular slits are compatible with...
In this paper, we propose a rate-splitting-based generalized multiple access (GMA) scheme for band-limited multi-user visible light communication (VLC) systems. By splitting and transmitting the input data of each user in a joint orthogonal multiple...
Structural colors based on all-dielectric metasurfaces hold great promise for a wide range of applications, including high-density optical storage, ultra-high-resolution 3D displays, imaging security certification, and so on. However, achieving dynam...
Optical surface scattering is an important subject in the field of optics. Previous studies of surface scattering mainly focused on the influence of surface topography and often ignored the influence of the mechanical property’s change caused b...
For a partially coherent Laguerre–Gaussian (PCLG) vortex beam, information regarding the topological charge (TC) is concealed in the cross-spectral density (CSD) function phase. Herein, a flexible method for the simultaneous determination of th...
Two-dimensional angular distribution of terahertz emission from single-color filamentation of laser pulses is experimentally studied. The use of a polypropylene pipe makes it possible to transform the angular pattern of terahertz radiation from the o...
The aim of the present study was to evaluate changes in cutaneous blood flow detected by incoherent optical fluctuation flowmetry (IOFF) in diabetic patients with diagnosed microangiopathies. The study includes 52 patients with type 2 diabetes mellit...
In this paper, the 946/1030 nm dual-wavelength LG01 mode vortex laser is obtained by applying the intracavity cascade pumped structure and annular-beam end-pumped method, an innovative and pioneering exploration of the transverse mode of the dual-wav...
An electrodynamic system is described that provides the creation of an electromagnetic wave field of high intensity at a frequency of 1 THz due to a combination of accumulation in time and compression in space of a wave pulse coming from an electron...
Raman spectra have been excited by the radiation of lasers generatingon in the visible (532 nm) and near-IR (785 nm) ranges in a LiTaO3:Cr3+ (0.005 wt%) crystal. The obtained spectra were compared. Recorded Raman spectra contained bands in the range...
Optical coherence tomography (OCT) is used to obtain retinal images and stratify them to obtain the thickness of each intraretinal layer, which plays an important role in the clinical diagnosis of many ophthalmic diseases. In order to overcome the di...
We propose a perfectly vertical coupling scheme based on metasurface deflectors (meta-deflectors) and grating couplers (GCs). An approach for optimizing the GCs based on the Gaussian-fitting using the genetic algorithm is proposed. An meta-deflector...
Pulsed ytterbium-doped fiber amplifiers (YDFA) with ns-level signal width are important devices for obtaining high-power pulsed lasers. When some components in the amplifier are ineffective, e.g., the isolator or fiber is damaged, extra feedback ligh...
This paper investigates the directional beaming of metallic subwavelength slits surrounded by dielectric gratings. The design of the structure for light beaming was formulated as an optimization problem for the far-field angular transmission. A verti...
Nowadays, the ability to diagnose brain tumors intraoperatively and delineate their margins, as accurately as possible, is of primordial importance during surgery. However, the exact tumor boundaries and targets are difficult to find due to the simil...
High-resolution imaging with wide field of view (FoV) ground-based telescopes is often affected by skylight background and noise due to the detector, resulting in an inhomogeneous background. In this paper, we propose an improved method for spatial i...
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