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SNR of the coded aperture imaging system Opt. Rev. (IF 1.068) Pub Date : 2021-01-18 Jianwei Wang, Yan Zhao
In this paper, the expression for the SNR has been developed through the imaging model. It is concluded that the image SNR decreases with the increase of the number of light-emitting points of the target under the same hardware conditions and experimental parameters. Using uniform bright squares of different sizes as the target, the SNR of the reconstructed image is calculated. Simulation and prototype
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Uncalibrated photometric stereo refined by polarization angle Opt. Rev. (IF 1.068) Pub Date : 2021-01-16 Daisuke Miyazaki, Shuhei Hashimoto
Photometric stereo allows us to estimate the surface normal of an object based on its shading. In uncalibrated photometric stereo, the light source direction is unknown; thus, both the light source direction and surface normal should be estimated, which establishes an ill-posed problem with ambiguity in its solution. Consequently, assumptions should be made to uniquely determine the solution; however
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A Golay3 sparse aperture optical system of primary mirror with free-form surface Opt. Rev. (IF 1.068) Pub Date : 2021-01-12 Bin Chen, Quanying Wu, Junliu Fan
To image distant and dim objects, this paper designs a sparse aperture optical system with a small F number and a large filling factor. The design process is divided into three steps. To start with, the curvature radius and spacing of the primary and secondary mirrors are calculated under the guidance of the paraxial imaging theory. Then, based on the primary aberration theory, the conic coefficients
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Evaluation of gradient-index array alignment Opt. Rev. (IF 1.068) Pub Date : 2021-01-09 Akihiro Yamamura, Kazuhiko Oka, Norihiko Nishiguchi
A gradient-index (GRIN) array is used as an imaging unit in light-emitting diode (LED) printers. In this study, we measure tilts of GRINs in an array and analyze the intensity distribution of the image to clarify the tilting amount and to evaluate the relation between the GRIN tilt and the degradation of the image. The arrangement intervals of the GRINs are measured, and the GRIN tilts are calculated
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Influence of linewidth enhancement factor $$\alpha $$ α on self-mixing interferometry in solid-state lasers Opt. Rev. (IF 1.068) Pub Date : 2021-01-07 Ke Kou, Cuo Wang
Up to now, laser self-mixing interferometry (SMI) has been widely applied to numerous scientific and industry fields. A easily negligible parameter, linewidth enhancement factor \(\alpha \), influences the inclination of SMI signals, and larger \(\alpha \) generally indicates more inclined fringes. It is demonstrated in the paper that solid-state lasers (SSL) have smaller linewidth enhancement factors
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Numerical analysis on the optical force calculation in the Rayleigh scattering regime Opt. Rev. (IF 1.068) Pub Date : 2021-01-07 Wenqiang Li, Huizhu Hu, Heming Su, Qi Zhu, Nan Li
The radiation force calculated in the Rayleigh regime is investigated by comparison with the generalized Lorenz Mie Theory (GLMT). The basic concepts behind the Rayleigh regime and GLMT are introduced, and a numerical simulation is conducted to analyze the difference between these two methods. Several physical parameters are considered to evaluate their effect on the calculation accuracy of the Rayleigh
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Gain-saturated two-pump fiber optical parametric amplifiers in the presence of dispersion fluctuation and fourth-order dispersion coefficient Opt. Rev. (IF 1.068) Pub Date : 2021-01-05 Le Cheng, Lei Yu, Nan Cao, Yufeng Zhang, Zhenyu Zhu, Hao Sui, Hongna Zhu, Stefano Taccheo, Bin Luo
The saturated gain performance of the two-pump fiber optical parametric amplifier (2-P FOPA) in the presence of random dispersion fluctuation as well as fourth-order dispersion coefficient are investigated. The gain spectra of the 2-P FOPA is simulated by solving the coupled equations numerically, considering the dispersion fluctuations along the fiber as a stochastic process with a given standard
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Nonlinearities effects on optical MIMO systems Opt. Rev. (IF 1.068) Pub Date : 2021-01-04 Ichraf Chatti, Faîçal Baklouti, Faouzi Chekir, Rabah Attia
Multimode fibers (MMF) are enjoying a renewed attention boosted by recent advances in multimode complex nonlinear optics. Reason behind nonlinearity is occurred either due to intensity dependence of the medium refractive index or to inelastic-scattering phenomenon. The most commonly occurred non-linear effects in optical Multiple Input Multiple Output (O-MIMO) are the Kerr, Stimulated Brillouin Scattering
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Effect of the restoration of saturated signals in hyperspectral image analysis and color reproduction Opt. Rev. (IF 1.068) Pub Date : 2021-01-04 Lu Yan, Masahiro Yamaguchi, Naoki Noro, Yohei Takara, Fuminori Ando
In hyperspectral imaging, the captured signal is often affected by saturation due to specular reflection or a peaky spectrum. In this paper, we propose a restoration method for saturated hyperspectral signals. Our algorithm is based on principal component analysis to obtain the reconstruction basis and then solve a linear constrained least square problem to calculate the coefficients of each basis
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Determination of optical properties in double integrating sphere measurement by artificial neural network based method Opt. Rev. (IF 1.068) Pub Date : 2021-01-03 Takahiro Nishimura, Yusaku Takai, Yu Shimojo, Hisanao Hazama, Kunio Awazu
An accurate inversion technique in double integrating sphere (DIS) measurement is essential for determining the optical properties of biological tissue. Although there are several established techniques, the computational time and complexity for spectral analysis require some approximations of the anisotropy factor g and refractive index n. We aim to demonstrate an artificial neural network (ANN) based
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Design of an omnidirectional gaze optical imaging system with ultrahigh resolution Opt. Rev. (IF 1.068) Pub Date : 2021-01-02 Shuai Liu, Chunyu Liu, Guang Jin, tiancong Wang
In this study, we discuss a new method to optimize the design of an omnidirectional gaze optical imaging system with ultrahigh resolution and long focus. An aspheric diffractive optical element is used in the optical system to offer more freedom, simplify the structure, and decrease the chromatic aberration. Owing to large image sensor arrays, the omnidirectional gaze photoelectric imaging system is
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Electrochemical parameters of aluminum oxide film in situ during anodization of aluminum by white light-optical interferometry Opt. Rev. (IF 1.068) Pub Date : 2021-01-01 Khaled Habib, Waleed Mohammad, Farzia Karim, Joydeep Dutta
Both Fabry–Pérot interferometry and the DC electrochemical method have been simultaneously used for the first time to measure in situ the anodic current density (J) of aluminum oxide films in 0, 2, 4, 5, 6, 8 and 10% sulfuric acid solutions (H2SO4). The calculated values of J by Fabry–Pérot interferometry were verified by the DC electrochemical method, i.e., a potentiostat, and the AC electrochemical
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Superimposing interferogram method using a multi-slit array to enhance sensitivity and interference definition of spatial-phase-shift interferometers Opt. Rev. (IF 1.068) Pub Date : 2020-10-27 Natsumi Kawashima, Tomoya Kitazaki, Kosuke Nogo, Akira Nishiyama, Kenji Wada, Ichiro Ishimaru
We propose a superimposing interferogram method to enhance the sensitivity and interference definition of spatial-phase-shift interferometers. The proposed method uses a multi-slit array as a redesigned field stop for the spatial-phase-shift interferometer. The widths of the apertural and blocked areas correspond to half the wavelength of the fringe pattern on the imaging plane and determine the wavelength
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Lightness modification method considering visual characteristics of protanopia and deuteranopia Opt. Rev. (IF 1.068) Pub Date : 2020-10-26 Meng Meng, Go Tanaka
We live in a colorful world, and it is important for us to receive visual information from colors in situations such as when we read a map. However, such important color-based information cannot be accurately received by some people. These people generally have some type of color vision deficiency such as protanopia or deuteranopia. It is important to realize their difficulties in recognizing differences
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Optical rotation conveyor belt based on a polarization-maintaining hollow-core photonic crystal fiber Opt. Rev. (IF 1.068) Pub Date : 2020-10-23 Heming Su, Nan Li, Chenge Wang, Qi Zhu, Wenqiang Li, Zhenhai Fu, Huizhu Hu
Hollow-core photonic crystal fibers (HCPCFs), a form of optical conveyer belts, have been used to guide particles for many years. However, only the translational motions of a guided particle can be manipulated. In contrast to traditional types, we demonstrate a new form of optical conveyor belts based on a polarization-maintaining hollow-core photonic crystal fiber (PMHCPCF). Because of the constant
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Fiber-optic distributed measurement of polarization beat length using slope-assisted Brillouin optical correlation-domain reflectometry Opt. Rev. (IF 1.068) Pub Date : 2020-10-11 Heeyoung Lee, Kohei Noda, Kentaro Nakamura, Yosuke Mizuno
We demonstrate distributed measurement of the polarization beat length along single-mode optical fibers (SMFs) using slope-assisted Brillouin optical correlation-domain reflectometry (BOCDR) with high spatial resolution, long measurement range, high sampling rate, and single-end accessibility. The beat lengths of SMFs wound on mandrels with radii of 10.5, 7.5, and 3.4 cm are measured to be 36.0, 18
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Two-point resolution in bright background under partially coherent light Opt. Rev. (IF 1.068) Pub Date : 2020-10-10 Kimiaki Yamamoto
Two-point resolution for ordinary microscopy was studied in a bright background under partially coherent light. The basic equation was derived from the unified theory of image intensity for two point-like objects for bright and dark backgrounds. For an extended Rayleigh’s criterion, it is shown that the two-point resolution in a bright background is noticeably different from that in a dark background
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Laser stripe extraction in additive manufacturing based on spatiotemporal noise regularization Opt. Rev. (IF 1.068) Pub Date : 2020-10-09 Haotian Yu, Chongchong Peng, Zhuang Zhao, Yi Zhang
The optical three-dimensional (3D) measurement technique based on the laser stripe has become increasingly important in additive manufacturing, which is necessary to extract the laser stripe accurately. In welding, the wrong laser stripe centers due to the high-brightness noise are usually extracted, which causes serious measurement error. In this paper, a laser stripe extraction algorithm based on
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Review paper: imaging lidar by digital micromirror device Opt. Rev. (IF 1.068) Pub Date : 2020-09-25 Yuzuru Takashima, Brandon Hellman
Applications of digital micromirror device for lidar are overviewed. A large Lagrange invariant value makes DMD as one of the attractive beam steering transmitter and receiver solutions for a time-of-flight lidar, especially with its an extended angular throw by synchronized pulsed laser illumination.
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Compressed holographic particle tracking velocimetry for microflow measurements Opt. Rev. (IF 1.068) Pub Date : 2020-09-24 Shuhei Yoshida, Kan Itakura
We have established a holographic particle tracking velocimetry (HPTV) technique based on compressed sensing (CS) for measurement of the velocity field of microflows in this study. In conventional HPTV, where the scattered light field is reconstructed via backpropagation calculations, the particle image spreads greatly in the depth direction and it is then difficult to perform three-dimensional three-component
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Error correction and evaluation in astronomical speckle interferometry with low-light CCD camera Opt. Rev. (IF 1.068) Pub Date : 2020-09-22 Susumu Kuwamura, Shotaro Ono, Noriaki Miura, Fumiaki Tsumuraya, Makoto Sakamoto, Naoshi Baba
In the astronomical speckle interferometry, low-light CCD cameras such as the electron bombarded/multiplying CCDs (EB/EMCCDs) are being widely used for taking the faint speckle images. The detector noise affects the power spectral estimate of the astronomical object as well as the speckle noise does. The estimation errors of the object power spectrum are results of the propagation of the random fluctuations
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13 W continuous-wave intracavity frequency-doubled Nd:YAP/LBO laser at 670.8 nm Opt. Rev. (IF 1.068) Pub Date : 2020-09-20 Xuchao Liu, Fengfeng Zhang, Zhimin Wang, Nan Zong, Yong Bo, Qinjun Peng, Dafu Cui, Zuyan Xu
We report on a high-power continuous-wave (CW) intracavity frequency-doubled laser at 670.8 nm, which is produced by the second-harmonic generation of a diode side-pumped Nd:YAP crystal laser with a type-II noncritically phase-matched LBO crystal. A maximum output power up to 13 W at 670.8 nm is obtained with an optical-to-optical \((808\mathrm{ nm}\to 671\mathrm{ nm})\) efficiency of 2.4%. The beam
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Digital holography-assisted 3-D bright-field image reconstruction and refocusing Opt. Rev. (IF 1.068) Pub Date : 2020-09-03 Syukran Hakim Bin Norazman, Tomoya Nakamura, Masahiro Yamaguchi
We propose an image reconstruction technique of a color 3-D object to perform image refocusing by combining information from bright-field image and digital holography. The key concept is first to reconstruct the 3-D object using compressive holography. Next, a binary mask is created to separate objects and transparent voxels. Then, the mask is used to assist the 3-D color object reconstruction from
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Multi-scale retinex-based contrast enhancement method for preserving the naturalness of color image Opt. Rev. (IF 1.068) Pub Date : 2020-08-31 Shi Bao, Shaoying Ma, Chuanying Yang
For images with insufficient visibility, image processing is required. Retinex theory is often implemented for image contrast enhancement for images with this characteristic. This paper proposes a multi-scale retinex-based contrast enhancement method using the illumination component; this method could preserve the naturalness of color images. In the proposed method, illumination was first modified
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Plasmonic color pixels fabricated by nanoimprint process Opt. Rev. (IF 1.068) Pub Date : 2020-08-27 Minoru Takeda, Ryo Takahara, Noriyuki Hasuike
Plasmonic nanostructures or metasurfaces have recently been actively researched for structural color generation. Controlling the plasmonic resonant wavelengths of surface plasmon polaritons excited along the metal dielectric interfaces, arising from the resonant interaction with incident electromagnetic waves, reflection or transmission color can be effectively tuned in the visible wavelength region
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An efficient lattice Boltzmann method for fluorescent diffuse optical tomography on GPUs Opt. Rev. (IF 1.068) Pub Date : 2020-08-26 Huandi Wu, Zhuangzhi Yan, XingXing Cen, Jiehui Jiang
Fluorescent diffuse optical tomography (FDOT) is an emerging imaging modality, with great prospects in areas such as biology and medicine. However, current FDOT encounters difficulty in simulating photon propagation in biological tissue, i.e., the forward problem, which limits its further application in biomedical research. This paper presents a lattice Boltzmann method (LBM) on the GPU to greatly
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Simulation on near-field light on recording medium generated by semiconductor ring resonator with metal nano-antenna for heat-assisted magnetic recording Opt. Rev. (IF 1.068) Pub Date : 2020-08-20 Ryuichi Katayama, Satoshi Sugiura
Heat-assisted magnetic recording (HAMR) is a promising technology for achieving more than 10 Tbit/inch2 recording density. A near-field transducer (NFT), which forms a small light spot on a recording medium, is necessary in HAMR. However, the heat generated by the NFT would melt the NFT itself. To solve this problem, the authors have proposed a novel device, in which a metal nano-antenna is attached
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Optical disc writing strategy for analog signal recording Opt. Rev. (IF 1.068) Pub Date : 2020-08-19 Kimihiro Saito
Optical discs are being sought as low-cost, earth-friendly storage candidates in response to increasing data volumes. To increase the recording density of optical disc, analog recording technique such as the Orthogonal Frequency Division Multiplexing (OFDM) method has been investigated. Since bitwise information is recorded on optical discs, it is necessary to create a column of marks corresponding
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Non-interferometric phase retrieval for collinear phase-modulated holographic data storage Opt. Rev. (IF 1.068) Pub Date : 2020-08-19 Jianying Hao, Yuhong Ren, Yuanying Zhang, Kun Wang, Hui Li, Xiaodi Tan, Xiao Lin
Because of its simple optical system setup and robust noise tolerance, non-interferometric phase retrieval is an important technique for phase-modulated holographic data storage. Usually, the iterative algorithm of non-interferometry needs hundreds of iteration numbers to retrieve phase accurately, the data transfer rate decreases severely. Strong constraints such as adding embedded data into the phase
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Point ahead angle prediction based on Kalman filtering of optical axis pointing angle in satellite laser communication Opt. Rev. (IF 1.068) Pub Date : 2020-07-28 Zhang Furui, Ruan Ping, Han Junfeng
Point ahead angle (PAA) prediction is important in space laser communication, but the existing methods have low accuracy and complicated calculation processes. In this paper, a new PAA prediction method is proposed based on Kalman filtering of the optical axis pointing trajectory. The proposed method uses the high precision of fine tracking to improve the accuracy of predictive filtering. Taking ground-satellite
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Multiplexed recording based on the reference wave correlation for computer-generated holographic data storage Opt. Rev. (IF 1.068) Pub Date : 2020-07-10 Yusuke Saita; Aoto Matsumoto; Naru Yoneda; Takanori Nomura
Holographic data storage (HDS) based on a computer-generated hologram (CGH) technique has been proposed as a promising approach to realize an in-line and simple HDS system. This work focuses on multiplexed recording for CGH-based HDS, and the approach based on the reference wave correlation is introduced to the HDS. For the proposed method, the processes for a CGH design are modified to generate reference
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The measurement and modeling investigation on the spectral polarized BRDF of brass Opt. Rev. (IF 1.068) Pub Date : 2020-07-09 Wangjiehui Ma; Yanlei Liu; Yufang Liu
Bidirectional reflectance distribution function (BRDF) offers complete description of the visual appearance properties of materials including the spectral and spatial characteristics. Numerous studies on BRDF have been performed for its important role in computer graphics, remote sensing, object characteristics analysis, and other fields. A few of these studies focus on the spectral polarized BRDF
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Image enhancement with lightness correction and image sharpening based on characteristics of vision for elderly persons Opt. Rev. (IF 1.068) Pub Date : 2020-06-05 Daiki Moriyama; Tadahiro Azetsu; Chiaki Ueda; Noriaki Suetake; Eiji Uchino
In general, as people age the functions of their sensory organs deteriorate. For example, in the eye of an elderly person, the visual field becomes dark owing to a decrease in the amount of light reaching the retina. Moreover, objects appear blurred due to a decrease in contrast sensitivity. In particular, the contrast sensitivity decreases remarkably as the spatial frequency increases. In this study
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An orthogonal-beam Doppler velocity measurement system based on a single laser diode Opt. Rev. (IF 1.068) Pub Date : 2020-05-30 Wei Liu; Wendi Yan; Yuan Wang; Chunlei Jiang; Yuhan Geng; Tao Yuan; Peng Chen
A novel method for analyzing a rotating target by an orthogonal-beam Doppler velocity measurement system on the basis of a single laser diode is presented. Using the method of fast Fourier transform after smoothing filter, we can obtain two groups of Doppler frequency shifts in the spectrum to calculate the velocity of a rotating target. A theoretical analysis and an experimental setup have been implemented
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HDR image reproduction based on visual achromatic response Opt. Rev. (IF 1.068) Pub Date : 2020-05-29 Geun-Young Lee; Hyuk-Ju Kwon; Sung-Hak Lee
High-dynamic range image reproduction using tone-mapping algorithms are used for image processing to reduce the dynamic range of a real scene to be displayed on low-dynamic range devices. General tone-mapping methods are associated with the determination of local parameters for tone compression and the halo artifact connected to detail enhancements. This paper proposes a lightness-preserved tone-mapping
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Achieving the polarization-manipulated multispectral perfect absorption and sensitive sensing via a metal/insulator/metal elliptical nanocavity array Opt. Rev. (IF 1.068) Pub Date : 2020-05-29 Wenjuan Cai; Yingcong Zhang; Shihua Cai; Xianping Wang; Jian Wu; Cheng Yin; Xingjiao Zhang; Wen Yuan; Qingqiang Kuang; Haimei Luo; Minghuang Sang
We present a polarization-manipulated multispectral perfect absorber based on a 2D metal/insulator/metal nanocavity array, in which a periodic structure of stacked Au–Al2O3 elliptical nanodisk is deposited on a bulk flat Au substrate. Theoretical analysis of the electromagnetic property showed that both the dipolar plasmon resonance and the plasmon cavity mode are the physical origins of the near-perfect
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A novel driving scheme for oil-splitting suppression in Electrowetting display Opt. Rev. (IF 1.068) Pub Date : 2020-05-24 Zhijie Luo; Junjun Fan; Jiazhi Xu; Guofu Zhou; Shuangyin Liu
To achieve quick-response Electrowetting displays with an accurate gray level performance for image applications, oil-splitting is an important issue which needs to be optimized. The study found that oil patterns affect the pixel aperture ratio. This paper proposes a novel driving waveform that can suppress an oil-splitting phenomenon without affecting the refresh rate. The experimental results show
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Best-fitting sphere of aspheric surface based on spherical aberration Opt. Rev. (IF 1.068) Pub Date : 2020-05-22 Bao-zhu Pan; Jing Tang
In order to understand the physical meaning of the best-fitting sphere of aspheric surface, based on the optical design idea of the aberration theory, the relationship between the curvature radius of the best-fitting sphere and the spherical aberration for the full aperture aspheric surface is set. The result is consistent with the traditional calculation method, which gets mainly from the geometric
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Multiple self-mixing interferometry based on lock-in amplifier analysis for vibration measurement Opt. Rev. (IF 1.068) Pub Date : 2020-05-19 Zihua Zhang; Fuli Wang; Tao Yuan; Chengwei Li
In this paper, a novel phase demodulation method for multiple self-mixing interferometry (MSMI) is proposed, which can improve the resolution and accuracy of vibration measurement in laser self-mixing interferometry (SMI). The sinusoidal phase modulation of the beam is obtained by an electro-optic modulator (EOM), and phase demodulation is performed by a lock-in amplifier analysis method. The phase
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Simulation of light scattering by two nano-sized circular cylinders using NS-FDTD method and interference analysis Opt. Rev. (IF 1.068) Pub Date : 2020-05-16 Dong Zhu; Chengtao Feng; Juan Huan; Kaibin Chu
Scattering problem by one cylinder whose radius is comparable to incident wavelength can be solved by Mie theorem. Due to complicated multiple scattering, scattering characteristics by two adjacent cylinders cannot be easily expounded. In this paper, high-accuracy non-standard finite-difference time domain (NS-FDTD) method is utilized to simulate electromagnetic field scattered by two nano-sized circular
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Mid-infrared dual-cladding photonic crystal fiber with high birefringence and high nonlinearity Opt. Rev. (IF 1.068) Pub Date : 2020-05-08 Zhiwei Shen; Keyao Li; Chunhua Jia; Hongzhi Jia
We propose two mid-infrared photonic crystal fibers with an elliptical As2S3 core and a dual-cladding structure with high birefringence and high nonlinearity. The cladding filling material is silica and the core material is As2S3. The full vector finite-element method is used to study the birefringence, and nonlinear coefficient of the structure in the 3–5 μm band. The Simulation results show that
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Trace gas detect based on spectral analysis and harmonic ratio Opt. Rev. (IF 1.068) Pub Date : 2020-05-04 Shuxin Yin; Yunfei Liu; Taiji Dong
A novel method of gas concentration calibration for tunable diode laser absorption spectroscopy, in which spectral analysis and harmonic signal intensity ratio measurement are combined, is proposed in this study. A harmonic signal is extracted from a transmitted light intensity by spectral analysis. The ratio of the second harmonic to the first harmonic is proportional to the gas concentration. The
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Dependence of macro-bending loss on bending configuration of multimode optical fibers studied by ray-tracing simulation Opt. Rev. (IF 1.068) Pub Date : 2020-04-28 Zhi Feng Zhang; Fei Ye; Xinxian Ma; Wenxia Zhao; Haibin Wang
The macro-bending loss of multimode step-index helical, s-shaped, and figure-of-eight-shaped optical fibers is investigated by ray-tracing simulation. In particular, fibers with the same radius of curvature having the three different configurations are compared. It is found that macro-bending loss strongly depends on the configuration as well as the bending curvature of the fibers. For the same curvature
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Improved 3D reconstruction method based on the Scheimpflug principle Opt. Rev. (IF 1.068) Pub Date : 2020-04-24 Yong Zhang; Yunfei Wang; Yucheng Qian; Shanlin Liu
This paper proposes a 3D reconstruction scheme for monocular cameras based on an improved line structure cursor positioning method and the Scheimpflug principle to overcome the limitations of current calibration methods for line-structured light 3D reconstruction and binocular stereo vision matching. Unlike the traditional line structure cursor positioning method, the line-structured light is projected
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A rotating holographic imager for stationary cloud droplet and ice crystal measurements Opt. Rev. (IF 1.068) Pub Date : 2020-03-26 Ville A. Kaikkonen; Eero O. Molkoselkä; Anssi J. Mäkynen
An optical cloud droplet and ice crystal measurement system ICEMET (icing condition evaluation method), designed for present icing condition monitoring in field conditions, is presented. The aim in this work has been to develop a simple but precise imaging technique to measure the two often missing parameters needed in icing rate calculations caused by icing clouds—the droplet size distribution (DSD)
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Ultracompact and dynamically tunable plasmonic THz switch based on graphene microcavity metamaterial Opt. Rev. (IF 1.068) Pub Date : 2020-03-25 Shaopeng Li; Yajie Xie; Jianling Meng; Wei Du; Jing Zhou
We propose and discuss a compact and tunable plasmonic terahertz (THz) metamaterial switch based on graphene microcavity. Due to the joint effect of graphene plasmon resonances and Fabry–Perot oscillations, this metamaterial structure can be switched from the ON state to OFF state with the maximum intensity attenuation larger than 95% (ON–OFF ratio larger than 30 dB). The central frequency of the switch
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Design of on-chip optical logic gates in 2D silicon photonic crystal slab Opt. Rev. (IF 1.068) Pub Date : 2020-03-20 Rui-hua Yuan; Chen Wang; Zhi-yuan Li
We have demonstrated the design of two types of on-chip optical logic gates in 2D silicon PC slab, which can support AND and XOR logic gate functions at different input frequencies. Different shapes of the center directional emitting cavity and different input/output directions can lead to different logic operations without nonlinearity or magnetism. More complicated logic networks can be built based
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Signal-source estimation from magnetic field image obtained using atomic magnetometer and digital micro-mirror device Opt. Rev. (IF 1.068) Pub Date : 2020-03-13 Shuji Taue; Yoshitaka Toyota
Visualization of an electromagnetic field distribution is helpful for spatial evaluation of field leakage and can aid in solving inverse problems of signal-source estimation. Optical detection is more accurate and less invasive than other methods owing to a low metal content in the sensing probes and signal wires. We have previously reported optical detection of alternating magnetic fields using an
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Numerical analysis of power generation characteristics in beam irradiation control of indoor OWPT system Opt. Rev. (IF 1.068) Pub Date : 2020-03-10 Jing Tang; Kazuhito Matsunaga; Tomoyuki Miyamoto
PurposeOptical wireless power transmission (OWPT), a new WPT alternative, is a promising solution to tackle the challenges like providing over watt-level power over meter-level distance that conventional WPT technologies face, to provide convenient and perpetual energy supply to the internet of things (IoT), mobile devices, and other various electrical equipments. In the OWPT system, in a room which
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Spectral and temporal optical signal generation using randomly distributed quantum dots Opt. Rev. (IF 1.068) Pub Date : 2020-03-06 Suguru Shimomura; Takahiro Nishimura; Yuki Miyata; Naoya Tate; Yusuke Ogura; Jun Tanida
Quantum dots (QDs) have a great potential for realizing information processing because of their signal-modulation capability based on energy transfer. We present a method for generating diverse temporal and spectral signals based on the energy transfer between multiple QDs. The method uses randomly distributed QDs, so it is not necessary to precisely arrange a QD network. With multiple energy transfers
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OFDM tolerance to additive white Gaussian and laser phase noises in optical heterodyning systems accompanied by the feasible pilot-assisted equalization Opt. Rev. (IF 1.068) Pub Date : 2020-03-05 David Zabala-Blanco; Cesar A. Azurdia-Meza; Samuel Montejo-Sánchez; Ali Dehghan Firoozabadi
It is well known that the performance of orthogonal frequency division multiplexing (OFDM) is limited by phase noise, which depends on the laser linewidths for coherent-detection radio over fiber (RoF) systems. In this manuscript, we present numerical and theoretical results to analyze the combined effects of phase and additive white Gaussian noises in the performance of RoF-OFDM schemes with the feasible
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Calibration of Near-Infrared Detectors Using a Wavelength Tunable Light Source Opt. Rev. (IF 1.068) Pub Date : 2020-02-17 Kinza Maham; Anna Vaskuri; Farshid Manoocheri; Erkki Ikonen
This paper presents the spectral responsivity calibrations of two indium gallium arsenide (InGaAs) and one germanium based near-infrared photovoltaic detectors using a wavelength tunable laser source based on a supercontinuum laser developed at the Metrology Research Institute, Aalto University. The setup consists of a supercontinuum laser based on a photonic crystal fiber as the light source, a laser
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Low-coherence interferometer with 10 MHz repetition rate and compensation of nonlinear chromatic dispersion Opt. Rev. (IF 1.068) Pub Date : 2020-02-14 Masaharu Hoshikawa; Katsuhiro Ishii; Takeshi Makino; Takahiro Hashimoto; Hideaki Furukawa; Naoya Wada
We developed a low-coherence interference measurement system using the time-stretch dispersive Fourier transformation technique and demonstrated 10 MHz measurements of the interference signal. We estimated the path length distribution by performing Fourier transformation of the interference signal. The estimated path length difference agreed with the set value. However, as the path length increased
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Measurement setup for differential spectral responsivity of solar cells Opt. Rev. (IF 1.068) Pub Date : 2020-02-12 Petri Kärhä; Hans Baumgartner; Janne Askola; Kasperi Kylmänen; Benjamin Oksanen; Kinza Maham; Vo Huynh; Erkki Ikonen
We have developed a setup for measuring differential spectral responsivities of unifacial and bifacial solar cells under bias light conditions. The setup uses 30 high-brightness LEDs for generating a quasi-monochromatic light source covering the wavelength range 290–1300 nm. Halogen lamps are used to generate bias-lighting conditions up to the irradiance level of 1000 W/m2. The setup has been fully
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Single-pixel camera with hole-array disk Opt. Rev. (IF 1.068) Pub Date : 2020-02-12 Yoshio Hayasaki; Ryo Sato
A single-pixel camera is composed of optical coding masks, a photo detector, and a computational decoder as the important feature that it requires no image sensor for imaging, and therefore has very simple optical and electrical architectures. The optical coding masks, the implementation of which is a novel point of our research, are composed of holes on a substrate and are arranged on the circumference
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Predictable quantum efficient detector for low optical flux measurements Opt. Rev. (IF 1.068) Pub Date : 2020-02-06 Santeri Porrasmaa; Timo Dönsberg; Farshid Manoocheri; Erkki Ikonen
The predictable quantum efficient detector (PQED) is a primary standard of optical power, which utilizes two custom-made induced-junction photodiodes that are mounted in a wedged trap configuration for the reduction of reflectance losses. PQED photodiodes of p-type and n-type were characterized for their dark current dependence on reverse bias voltage at room temperature. As simulations predict that
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Predicting scattering properties of fiber suspensions using Mie theory and probabilistic cross-sectional diameter of fibers Opt. Rev. (IF 1.068) Pub Date : 2020-02-06 Harri J. Juttula; Matti Törmänen; Anssi J. Mäkynen
Scattering of visible light by micrometer-scale natural wood fibers is usually treated by assuming fibers to be perfect long cylindrical scatterers. In industrial processes, however, fibers experience deformations and are far from ideal cylinders. Variation in fiber morphology affects their scattering properties and it poses a challenge for reliable process measurements. In this paper, we have studied
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Laser beam scattering for the detection of flat, curved, smooth, and rough microplastics in water Opt. Rev. (IF 1.068) Pub Date : 2020-02-03 Benjamin O. Asamoah; James Amoani; Matthieu Roussey; Kai-Erik Peiponen
Microplastic (MP) pollution is alarming and poses an imminent threat to the environment with a direct impact on our health and that of fauna in natural water bodies. The understanding of light–MP interactions in water as well as the need for low-cost and robust optical sensors for the detection of MPs that appear everywhere is, therefore, necessary. We have demonstrated the use of a prototype optical
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Simulated reflectance spectra and point spread functions in database constructed by moderate grouping of nine layers in skin model Opt. Rev. (IF 1.068) Pub Date : 2020-02-03 Kaustav Das; Tomonori Yuasa; Izumi Nishidate; Hideki Funamizu; Yoshihisa Aizu
This paper presents a numerical study on simulated spectra and point spread functions in the database that we constructed by moderate grouping of nine layers in a skin model. The database is used for identification of a simulated skin reflectance spectrum which seems most closed to a certain target spectrum or a measured spectrum. On the basis of the properties of absorption and scattering coefficients
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Effect of optical filters and light source spectra on the spectral luminous efficiency function measurement Opt. Rev. (IF 1.068) Pub Date : 2020-01-21 Yajing Ji; Wenyi Li; Muqing Liu; Haiping Shen
During the measurement of spectral luminous efficiency function \(V\left( \lambda \right)\), monochromatic visual stimuli of higher luminance can be obtained by narrow band optical filters with broad band light sources, compared to monochromators. However, the distortion of \(V\left( \lambda \right)\) is inevitably caused due to the bandwidth of the optical filters. In this paper, the effect of optical
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