Contents
2009
Volume: 29 Issue 1
49 Article(s)
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Atmospheric Optics and Oceanic Optics
Influence of Transmissivity in Savart Polariscope on Throughput of Spatially Modulated Polarization Interference Imaging Spectroscope
Wu Junfang, and Liu Hanchen
The interferometer is core of spatially modulated polarization interference imaging spectroscopy, the key component of the interferometer is Savart polariscope. The throughput of spatially modulated polarization interference imaging spectroscope is directly determined by transmissivity in Savart polariscope, thus affecThe interferometer is core of spatially modulated polarization interference imaging spectroscopy, the key component of the interferometer is Savart polariscope. The throughput of spatially modulated polarization interference imaging spectroscope is directly determined by transmissivity in Savart polariscope, thus affects forming the interferogram and target image. There is necessary to study the influence of transmission in Savart polariscope on throughput. After introducing the structure of interferometer, on the basis of electromagnetic field boundary conditions and the law of refraction-transmission and light intensity were obtained in Savart polariscope of the four interfaces: air /the left plate of Savart polariscope; the left plate of Savart polariscope/adhesive; adhesive/the right plate of Savart polariscope; the right plate of Savart polariscope/air, at the same time the light intensity is got after the two light beams interfere in through interferometer.The interference overall intensity is obtained by using light superposition principle,the mathematical expression of the transmissivity and throughput is solved. Through the relationship between the transmissivity and throughput, the influence of transmissivity in Savart polariscope on throughput can be intuitively known, this may provide a theoretical basis for the study of spatially modulated polarization interference imaging spectroscopy..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 93 (2009)
Experimental Research of Laser Beam Cleanup for Dynamic Aberrations Based on Stochastic Parallel-Gradient-Descent Method
Wang Sanhong, Liang Yonghui, Long Xuejun, and Yu Qifeng
A beam cleanup subsystem is usually contained in high power laser system to correct for the wavefront aberrations of the output beam of the laser resonator continuously. To investigate the feasibility of the stochastic parallel gradient descent (SPGD) adaptive optics method on beam cleanup issue, dynamical wavefront abA beam cleanup subsystem is usually contained in high power laser system to correct for the wavefront aberrations of the output beam of the laser resonator continuously. To investigate the feasibility of the stochastic parallel gradient descent (SPGD) adaptive optics method on beam cleanup issue, dynamical wavefront aberrations, analogous to the commonly encountered wavefront distortions in high power laser beams, are first introduced into the experimental laser beam by continuously changing the surface shape of a 37-element deformable mirror incorporated in the system according to the iteration sequence of the SPGD algorithm, and then the same deformable mirror is used to correct for the produced aberrations by applying the SPGD algorithm to upgrade the control voltages of the mirror actuators. The experimental results show that, when the initial aberrations of the system being removed, the dynamic wavefront aberrations of the laser beam can be compensated successfully and the beam quality remains on a high level during the whole correction period with the system working on simulated iteration rates of 1 kHz and 2 kHz respectively. It is indicated that the SPGD adaptive optics method is feasible on beam cleanup system..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 97 (2009)
Development of Real-Time Hyperspectral Radiation Sea-Observation System
Yang Yuezhong, Cao Wenxi, Sun Zhaohua, and Wang Guifen
A hyperspectral system for real-time observation of ocean color is developed. The system includes three main units: an optical-fiber-based hyperspectroradiometer for in situ measurements of upwelling radiance and downwelling irradiance both at sea surface and at underwater depths, a moored buoy platform suitable for loA hyperspectral system for real-time observation of ocean color is developed. The system includes three main units: an optical-fiber-based hyperspectroradiometer for in situ measurements of upwelling radiance and downwelling irradiance both at sea surface and at underwater depths, a moored buoy platform suitable for loading the hyperspectroradiometers and other auxiliary sensors, and an electrionic system for data acquisition and real time data communication. A six-channel optical fiber spectroradiometer is designed, which can simultaneously measure parameters at different depths. The large dynamic range of the spectroradiometer is achieved by auto-adjusting the integration time of CCD array detector. The use of optical fiber makes it possible to minimize the collector of sensor, and thus the instrument self-shading effect is reduced. An auto-driving mechanical brush is designed for optical sensor, which prevents the sensors from bio-fouling and enables the sensors to work well underwater. The characteristics of the system were tested in laboratory, and the buoy was deployed in near-shore waters for 36 days in situ experimental testing. Experimental results show that, the errors for the optical parameters are within ±5%, and the buoy has a good stability at high sea state conditions, and the data acquisition and electronic communication system is reliable and effective..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 102 (2009)
Phase Function of Prolate Spheroidic Mono-Disperse Aerosol Particles
Shao Shiyong, Huang Yinbo, Wei Heli, and Rao Ruizhong
Typical particles such as ice crystal, dust and black carbon are selected. to study the changing tendency of scattering phase function with prolate spheroidic mono-disperse aerosol particles with different aspect ratio, size parameter and refractive index by T-matrix. When the imaginary part of refractive index is neglTypical particles such as ice crystal, dust and black carbon are selected. to study the changing tendency of scattering phase function with prolate spheroidic mono-disperse aerosol particles with different aspect ratio, size parameter and refractive index by T-matrix. When the imaginary part of refractive index is neglected, for ice crystal with aspect ratio of 0.4 and spherical particle with the same surface area, their phase function ratio, ρ, is divided into five regions: 1) ρ≈1, the region of nearly direct forward scattering, 2) ρ>1, from about 5° to 30°, 3) ρ<1, from about 30°～35° to 80°～110°, 4) ρ1, from about 80°～110°to 150°～160°, 5) ρ1, the field after 160°. In the same circumstances, for the change of refractive index, the field of ρ<1 for dust spreads to a larger angle region, but that corresponding to the fields of ρ1 and ρ1 all shrinks, however the number of ρ-value regions of carbon reduces to 3 since the regions of ρ1 and ρ1 disappear. Theoretical foundation is provided with measurement of aerosol to distinguish prolate spheroidic particles..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 108 (2009)
Generation of Rectangular Turbulence Phase Screens Based on Fractal Characteristics of Distorted Wavefront
Wu Hanling, Yan Haixing, Li Xinyang, and Li Shushan
In numerical simulation of light propagation through the atmosphere with the phase compensation by an adaptive optical system including temporal evolution, such as very long exposure imaging and simulation of the dynamic control process in an adaptive optical system, the generation and application of rectangular turbulIn numerical simulation of light propagation through the atmosphere with the phase compensation by an adaptive optical system including temporal evolution, such as very long exposure imaging and simulation of the dynamic control process in an adaptive optical system, the generation and application of rectangular turbulence phase screens are critical. But the widely-used spectral approach can only generate square phase screen, and wastes the computational resource because only a rectangular portion of the square phase screen is practically utilized. Furthermore, the spectral phase screen needs low-frequency modification, so that needs more computation. Based on the fractal characteristics of turbulence-distorted wavefront, a new algorithm for generating rectangular turbulent phase screen is proposed. The phase structure function of generated phase screens agrees well with the theoretical one. Compared with existing approaches, the present algorithm shows obvious advantages: simplicity, high efficiency and less computation resource. The generated phase screen agrees with theoretical results from turbulent statistical characteristics, in the low- and high-frequency region..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 114 (2009)
Diffraction and Gratings
Effect of Incident Angle on Diffraction Efficiency of a Two-Layer Diffractive Optical Element
Pei Xuedan, Cui Qingfeng, and Leng Jiakai
Diffractive surface of a two-layer diffractive optical element (DOE) is simulated approximately by step surface of binary optical element, and phase shift of a two-layer DOE for light of oblique incidence is deduced from phase shift of a single-layer binary optical element. The expression of diffraction efficiency of tDiffractive surface of a two-layer diffractive optical element (DOE) is simulated approximately by step surface of binary optical element, and phase shift of a two-layer DOE for light of oblique incidence is deduced from phase shift of a single-layer binary optical element. The expression of diffraction efficiency of the two-layer DOE is presented. Simulation shows that the diffraction efficiency of a two-layer DOE changes slightly when the incident angle is small, but it decreases greatly when incident angle increases. Diffraction efficiency changes little when the incident angle increases to 4.5°, decreases slowly to 95% when the incident angle increases 6.7°, decreases to 80% when the incident angle change increases to 9.5°, and decreases rapidly to zero when the incident angle increases to 18°..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 120 (2009)
Diffraction Properties of Ultra-Short Pulsed Gaussian Laser Beam by Transmission Volume Grating
Zheng Guangwei, Liu Li, He Yanlan, Tan Jichun, Zheng Haobin, Wang Xiao, and Wang Xiaodong
Based on Fourier transform, the ultra-short pulsed Gaussian laser beam is transformed into linear combinations of monochromatic plane waves. Depending on Kogelnik′s one-dimensional coupled-wave theory, the diffraction characteristics of monochromatic plane waves by transmitting volume grating are put forward, when the Based on Fourier transform, the ultra-short pulsed Gaussian laser beam is transformed into linear combinations of monochromatic plane waves. Depending on Kogelnik′s one-dimensional coupled-wave theory, the diffraction characteristics of monochromatic plane waves by transmitting volume grating are put forward, when the central wave vector satisfies the Bragg condition of the volume grating. With the inverse Fourier transform of diffraction of monochromatic plane waves, the law of spatial and temporal intensing distribution of diffractive beam with different parameters of volume grating is given. The results show that diffractive laser beam is broadened in the temporal and spatial domains, in the plane comprising of the grating vector and the normal vector of the grating front surface, with the decreasing period of the transmitting volume grating. Its broadening trend in the spatial domain is faster than that in the temporal domain. Compared with input ultra-short pulsed Gaussian laser beam, the diffractive laser beam is deteriorated obviously in the spatial domain. Diffractive laser beam is broadened in the temporal and spatial domains in the plane comprising of the grating vector and the normal vector of the grating front surface, with the increasing thickness of the grating. And its broadening trend is equal to each other in the spatial and in temporal domains. Compared with the input ultra-short pulsed Gaussian laser beam, the diffractive laser beam is deteriorated both in the temporal and spatial domains..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 126 (2009)
Fiber Optics and Optical Communications
Synthetic Aperture Imaging Ladar (Ⅳ): Unified Operation Mode and Two-Dimensional Data Collection Equation
Liu Liren
A unified operation mode of synthetic aperture imaging ladar (SAIL) with its linear moving and the footprint scanning is proposed. Moreover, we define a kind of two-dimensional (2-D) data collection equation based on the developed point target ladar equation, which is a complete mathematical description of data acquisiA unified operation mode of synthetic aperture imaging ladar (SAIL) with its linear moving and the footprint scanning is proposed. Moreover, we define a kind of two-dimensional (2-D) data collection equation based on the developed point target ladar equation, which is a complete mathematical description of data acquisition for 2-D SAIL imaging. The unified mode can be decomposed into strip-map mode, spotlight mode, sliding spotlight mode and beam scanning mode, and each correspondingly has a simplified 2-D data collection equation. The beam scanning mode with only the footprint scanning is a new mode, and has special applications..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 1 (2009)
Generalized Orthogonal Iterative Algorithm for Pose Estimation of Multiple Camera Systems
Xu Yunxi, Jiang Yunliang, and Chen Fang
It still lacks of systematic method for solving pose estimation of a multiple camera system (MCS). The pose-estimation problem is usually achieved by solving the Perspective-n-point problem or finding the least-squared-error rigid transformation between two 3D point sets. They have limitations. The orthogonal iterationIt still lacks of systematic method for solving pose estimation of a multiple camera system (MCS). The pose-estimation problem is usually achieved by solving the Perspective-n-point problem or finding the least-squared-error rigid transformation between two 3D point sets. They have limitations. The orthogonal iteration (OI) algorithm is charalteristic can converge fast and globally is based on points. And it is one of the state-of-art real-time pose estimation algorithms and used widely. A generalized iterative algorithm is proposed. It is a universal multi-view algorithm for pose estimation. In the method, all images acquired from the cameras are treated as a whole, and the relative pose parameter is calculated this method, datum of multiple cameras is unified, and the sum of object-space collinearity error of feature points all cameras sensed is used as error function for MCS. An iterative algorithm is developed to minimize the error function. The experiment result demonstrates its effectiveness and superiority of the algorithm for pose estimation of MCS..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 1, 6 (2009)
Simulation Research on Wavefront Sensing and Correction Algorithms for Segmented Space Telescope
Zhang Xiaofang, Dong Bing, Huang Yifan, Mao Heng, Wang Shanshan, and Yu Xin
Wavefront sensing and control algorithms play a very important role in high-resolution imaging of segmented space telescope. In this paper, a coaxial three-mirror anastigmat system is modeled by Zemax and the primary mirror is a segmented design. After space telescope deployment, the wavefront errors have a wide dynamiWavefront sensing and control algorithms play a very important role in high-resolution imaging of segmented space telescope. In this paper, a coaxial three-mirror anastigmat system is modeled by Zemax and the primary mirror is a segmented design. After space telescope deployment, the wavefront errors have a wide dynamic range in amplitude and spatial frequency, so a multistage wavefront correction control strategy is proposed to reduce wavefront errors gradually. The wavefront correction process and the wavefront sensing and correction algorithms performed in each step are given in detail. Integrated simulation software is developed to verify our algorithms. Wavefront correction results of segmented primary mirror give a good demonstration of the feasibility of our algorithms..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 7 (2009)
Studies on Energy Expending and (u, v) Coverage for Optical Synthetic Aperture Camera on Geosynchronous Orbit
Jiang Yuesong, Wang Haiyang, Qiu Zhiwei, Zhang Li, and Zhou Bo
To meet the needs of high resolution of real time imaging for earth observation, we studied the cases of energy expending and spatial spectra (u, v) coverage for optical synthetic aperture camera which is composed of distributed satellite system at geosynchronous earth orbit. Based on the orbital dynamics, we analysed To meet the needs of high resolution of real time imaging for earth observation, we studied the cases of energy expending and spatial spectra (u, v) coverage for optical synthetic aperture camera which is composed of distributed satellite system at geosynchronous earth orbit. Based on the orbital dynamics, we analysed energy expending of collector satellite, which is keeping formation of optical synthetic aperture array at zenith-nadir direction and non zenith-nadir direction, and simulation computed results are given. Based on high quality of imaging, we studied the case of (u, v) coverage of various time of day at zenith-nadir direction and latitude 20° on earth surface of direction. The methods and results obtained can be also apllied to the cases synthetic aperture system such as space-based orbital (i.e. low earth orbital, deep space detection etc.) and various spectrum (i.e. millimeter-wave, microwave etc.), and have very important reference values for developing high-resolution imaging of earth observations etc...
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 12 (2009)
Simulation of Space-Borne Altimeter Based on Pseudorandom Modulation and Single-Photon Counting
Yang Fu, He Yan, Zhou Tianhua, and Chen Weibiao
A method combining pseudorandom modulation of the fiber laser and single-photon counting is proposed to realize a high spatial resolution for the space-borne laser altimeter. The detailed principle of detection is presented, and the equation of the signal-to-noise ratio for the altimeter is given. The relationships betA method combining pseudorandom modulation of the fiber laser and single-photon counting is proposed to realize a high spatial resolution for the space-borne laser altimeter. The detailed principle of detection is presented, and the equation of the signal-to-noise ratio for the altimeter is given. The relationships between the signal-to-noise ratio with the laser power and the receiving telescope aperture are numerically simulated. The relationships between the parameters and the optimized parameters are obtained after analysis. Results show that the space-borne altimeter can reach the signal-to-noise ratio of 10, and the distance resolution of 15 cm when the receiving telescope aperture is between 0.8 m and 1m, laser power is about 10 W, pseudorandom modulation pulse width is 600 μs, modulation frequency is 1 GHz. This system can meet the requirement of altimetric measurement under the condition of space-borne environment..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 21 (2009)
Current Situation of Ultra-Precision Bonnet Polishing Key Technology of Optical Elements
Zhang Wei, Li Hongyu, and Yu Guoyu
Space optical elements require highly surface shape precision and surface quality. Bonnet polishing, with new polishing tool and special motion trait, is a high precision and efficient optical component machining method, especially for aspheric surface machining. It has a extensive application prospect. Principle and dSpace optical elements require highly surface shape precision and surface quality. Bonnet polishing, with new polishing tool and special motion trait, is a high precision and efficient optical component machining method, especially for aspheric surface machining. It has a extensive application prospect. Principle and developing process of related bonnet polishing technology are analyzed, and research situation and test result of bonnet polishing technology are introduced. Current situation of several important and critical technologies is reviewed. The removing characteristics material, control algorithm of resident time, control of marginal precision and latest-developed spray polishing technology are introduced significantly..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 27 (2009)
Aberration Correction of Czerny-Turner Imaging Spectrometer Carried by Satellite
Xue Qingsheng, Wang Shurong, and Lu Fengqin
To avoid the problems of the classical Czerny-Turner imaging spectrometer, such as large aberration and low spatial resolution, a novel method of aberration correction for Czerny-Turner imaging spectrometer carried by satellite is developed. The principle and method of aberration correction are deduced in detail. A desTo avoid the problems of the classical Czerny-Turner imaging spectrometer, such as large aberration and low spatial resolution, a novel method of aberration correction for Czerny-Turner imaging spectrometer carried by satellite is developed. The principle and method of aberration correction are deduced in detail. A design example operating in 540～850 nm wavelength band with 2.3°field of view, 114.8 mm focal length, 3.81 F number is designed. The ray tracing and optimization for the optical system are carried out with Zemax software. The results demonstrate that the aberration of the optical system is substantially corrected, and the modulation transfer function of total field of view is more than 0.58, which satisfies the requirement, and proves the feasibility of the method..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 35 (2009)
Calibration of the Visible and Near-Infrared Channels of the FY-2C/FY-2D GEO Meteorological Satellite at Radiometric Site
Li Yuan, Zhang Yong, Liu Jingjing, Rong Zhiguo, Zhang Lijun, and Zhang Yuxiang
In order to calibrate the visible and near-infrared channels of FY-2C & FY-2D’s visible and infrared spin-scanning radiometer (VISSR), National Satellite Meteorlogical Center (NSMC) associated with other organizations went to China radiometric calibration site of remote sensing satellite-Dunhuang to take site vicarIn order to calibrate the visible and near-infrared channels of FY-2C & FY-2D’s visible and infrared spin-scanning radiometer (VISSR), National Satellite Meteorlogical Center (NSMC) associated with other organizations went to China radiometric calibration site of remote sensing satellite-Dunhuang to take site vicarious calibration synchronous experiment. The experiment continued for three months and a lot of experimental data have been gotten. From four days’ experimental data, the calibration coefficients with relative standard deviations below 5.6% (FY-2C) and 2.4% (FY-2D) are calculated. The reflectance of Dunhuang was corrected by the bidirectional reflectance distribution function (BRDF) model calculated by Liu Jingjing, the apparent reflectance was calculated by the use of 6S model and was corrected by the sun zenith cosine and sun-earth distance. From the different experimental data measured in different field conditions and sun position, the accordant calibration coefficients were gotten, and it showed the veracity and stability of the calibration arithmetic..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 41 (2009)
Simulation of Nonlinear-Chirp Compensation by Scan-Filtering in SAIL
Xu Nan, Lu Wei, and Liu Liren
The nonlinear chirp of laser reduces the range resolution of synthetic aperture imaging ladar. Based on the nonlinear chirp measurement in reference channel and phase-shift algorithm, a compensation method is proposed, which filters and proofreads the target backwave one by one, and mathematical flow of this method is The nonlinear chirp of laser reduces the range resolution of synthetic aperture imaging ladar. Based on the nonlinear chirp measurement in reference channel and phase-shift algorithm, a compensation method is proposed, which filters and proofreads the target backwave one by one, and mathematical flow of this method is established. The simulation of the airborne synthetic aperture imaging ladar model validates the feasibility. The effects of width of the scan filter and nonlinear chirp are discussed. The conclusion of adequate width of the scan filter is given..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 47 (2009)
On-Orbit Position Error Correction of Segmented Primary Mirror of High-Resolution Space Telescope
Dong Bing, and Yu Xin
A coaxial three-mirror anastigmat system with a segmented primary mirror is modeled in Zemax. A position error correction method for segmented mirror based on sensitivity matrix retrieval is proposed. For the annular-sector segmented primary mirror, the exit-pupil aberration is fitted with annular-sector Zernike orthogA coaxial three-mirror anastigmat system with a segmented primary mirror is modeled in Zemax. A position error correction method for segmented mirror based on sensitivity matrix retrieval is proposed. For the annular-sector segmented primary mirror, the exit-pupil aberration is fitted with annular-sector Zernike orthogonal polynomials. The sensitivity matrix of segmented mirror is calculated and the linear relationship between segment position error and exit-pupil aberration variation is verified. Simulation results show that the optical system can be recovered to the design state on condition that the segment has five corrective degrees of freedom, but small residual errors will remain in three degrees of freedom correction..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 55 (2009)
Influence of Satellite Retroreflector Precision on Far-Field Diffraction Pattern
Zhou Hui, Li Song, Zheng Guoxing, and Gao Junling
Satellite retroreflector is used as laser ranging cooperative target to improve the intensity of reflected beam, which has close relationship with processing parameters of the retroreflector. Based on geometrical structure of retroreflector and vector form of reflection-refraction law, mathematical models with phase diSatellite retroreflector is used as laser ranging cooperative target to improve the intensity of reflected beam, which has close relationship with processing parameters of the retroreflector. Based on geometrical structure of retroreflector and vector form of reflection-refraction law, mathematical models with phase distribution of returned beam, and far-field diffraction pattern (FFDP) are built up for retroreflector with dihedral angle error and flatness error. As for retroreflector with circular section, FFDP under different incident conditions of laser beam, dihedral angle error and flatness error is simulated. Meantime, the rules of their effect on FFDP are analysed at length. Simulated results express that the divergence of FFDP is increased with dihedral angle error, flatness error and laser incident angle. In terms of FFDP and velocity aberration compensation theory, a new method of using dihedral angle offset for compensating velocity aberration in large observation range is put forward..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 60 (2009)
Waveband Selection for Space Target Detection and Identification
Li Yanan, Sun Xiaobing, and Qiao Yanli
Based on the measured spectral reflectivity and the spectral signature of atmosphere radiation, a waveband selection method is given to detect target outside atmosphere. The reflection spectra of the samples and standard board are measured, and the spectral reflectivity of the samples is obtained. In order to improve tBased on the measured spectral reflectivity and the spectral signature of atmosphere radiation, a waveband selection method is given to detect target outside atmosphere. The reflection spectra of the samples and standard board are measured, and the spectral reflectivity of the samples is obtained. In order to improve the target identification, waveband selection is proceeded after considering the target radiation, the spectral reflectivity, the background radiation, the target-background contrast, the transmittance of slanting path and so on. The typical spectral characteristics of the above considerations are calculated by the atmospheric transmission model software MODTRAN and analyzed. The results show that 0.76～0.90 μm is the optimal detection waveband for target with yellow aluminium-coated polyester thin-film, and 0.52～0.60 μm for target with silver aluminium-coated polyester thin-film..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 67 (2009)
Compression of Interference Multispectral Image Based on Adaptive Classification and Curve-Fitting
Wang Keyan, Li Yunsong, Wu Chengke, and Song Juan
By analyzing two characteristics of an interference multispectral image data, a compression algorithm based on adaptive classification and curve-fitting is proposed. The image is partitioned adaptively into intensive interference region and weak interference region by the mean square deviation criterion. Different fittBy analyzing two characteristics of an interference multispectral image data, a compression algorithm based on adaptive classification and curve-fitting is proposed. The image is partitioned adaptively into intensive interference region and weak interference region by the mean square deviation criterion. Different fitting functions are constructed for the two regions respectively. For the intensive interference region, some typical interference curves are selected to predict other curves, and they are fitted by least square method. For the weak interference region, the data of each interference curve are approximated independently. Finally all the approximating errors of two regions are entropy coded. The experimental results show that, compared with JPEG2000, the proposed algorithm not only decreases the average output bit-rate by about 0.2 bit/pixel for lossless compression, but also improves the reconstructed images and reduces the spectral distortion, especially at high bit-rate for lossy compression..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 78 (2009)
Automatic Method for Urban Roads Detection and Mapping Based on Remote Sensing Images
Sun Xian, Wang Hongqi, Zhang Zheng, and Huang Yu
For the purpose of applying the spatial observation technology into the urban geographical information system, a new method based on remote sensing images is proposed to detect and map urban roads automatically. It builds a hierarchical objects network to organize image structure, getting precise processing units. ThenFor the purpose of applying the spatial observation technology into the urban geographical information system, a new method based on remote sensing images is proposed to detect and map urban roads automatically. It builds a hierarchical objects network to organize image structure, getting precise processing units. Then the unsupervised learning integrating salient features is performed to analyze the explicit and implicit information, and to label the road targets in remote sensing images efficiently. It also applies spatial smoothing which incorporates contextual information to eliminate the adverse effects caused by background disturbance, occlusion and so on. After vectorization procedure, the contours and relative parameters of roads can be given. Experiments demonstrate that the proposed method achieves high exactness and robustness when detecting and mapping manifold roads in most high-resolution remote sensing images, and it is valuable for the urban information system and digital city-system construction..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 86 (2009)
Hybrid Space-Time Code for Free Space Optical Communication
Wang Huiqin, and Ke Xizheng
An orthogonal space-time block code suitable for intensity modulation/direct detection optical communication system is constructed by using orthogonality of pulse position modulation (PPM) after analyzing the effect of atmosphere on the optical signal. The technique is applied to the first layer of the layered space-tiAn orthogonal space-time block code suitable for intensity modulation/direct detection optical communication system is constructed by using orthogonality of pulse position modulation (PPM) after analyzing the effect of atmosphere on the optical signal. The technique is applied to the first layer of the layered space-time code (LST) to increase the diversity of the information symbol. The effect of other layers on the symbol is eliminated by using group interference suppression (GIS). The signal is recovered by combining the decoding method of space-time block code (STBC) and Bell Labs Louyered Space-Time (BLAST) and maximum likelihood decision rule. The feasibility of the technique is proved by the simulation experiment. It shows that in free space optical communication the error rate performance of hybrid space-time code is better than BLAST..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 132 (2009)
Dual-Channel PolSK Optical Transmissions Using SOA-Based All-Optical Polarization Modulations
Wang Lutang, Fang Nian, Wang Ying, and Huang Zhaoming
We propose and experimentally demonstrate a novel dual-channel polarization shift-keying (PolSK) optical transmission system, in which two semiconductor amplifiers (SOAs) are cascaded as two individual all-optical polarization modulators for each channel. The formed PolSK signals have four states of polarization (SOP),We propose and experimentally demonstrate a novel dual-channel polarization shift-keying (PolSK) optical transmission system, in which two semiconductor amplifiers (SOAs) are cascaded as two individual all-optical polarization modulators for each channel. The formed PolSK signals have four states of polarization (SOP), constituting two orthogonal binary data channels. Each channel can independently transmit data streams with different formats, bit rates and clock signals. The transmitted PolSK signals can be directly detected, it greatly simplifies the design of the receiver and eventually reduces the system cost. With this scheme, the system capacity for data transmissions can be doubled. Furthermore, due to the constant optical power of PolSK signals, the transmission system can enhance its tolerance to nonlinear effects in the fiber link, increase its long-distance transmission capacity. The SOPs of received signals are easily tracked by using two polarization stabilizers in each branch of the receiver, respectively, in order to achieve a stable signal receiving. The experimental setup based on the proposed scheme was constituted and several basic experiments were carried out for investigating the system’s performance. The long-distance data transmissions over 50 km, 80 km and 100 km fiber links, respectively, are carried out and the experimental results prove that the feasibility of our proposed scheme is validated..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 138 (2009)
Measurement Efficiency of High-Speed-Demodulation by Linear Filtering Method
Chen Xian, Yu Shangjiang, Yang Jixiang, and Lin Ming
The reflectivity spectrum of the fiber Bragg grating(FBG) will get wider when loaded in the unhomogeneous strain field, and error is brought into the measurement. Linear filtering method is used for high frequency wave demodulation. The demodulation process was simulated by transmission-matrix method with typical FBG pThe reflectivity spectrum of the fiber Bragg grating(FBG) will get wider when loaded in the unhomogeneous strain field, and error is brought into the measurement. Linear filtering method is used for high frequency wave demodulation. The demodulation process was simulated by transmission-matrix method with typical FBG parameters.The results show that the measurement error is lower than 3% when the peak strain is sticked to 3000 με and the strain wavelength is larger than 0.0025 m. The measurement error is lower than 0.25 % when the strain wavelength is 0.05 m and the peak strain is smaller than 10000 με. The numerical result agrees well with the experiment on the slide Hopkinson pressure bar..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 145 (2009)
Investigation on Packet Clock Recovery with Fastened Unlocking Time Using an Optical Band-Pass Filter
Zhang Aixu, Yu Jinlong, Wang Wenrui, Zhang Litai, and Han Bingchen
All-optical packet clock recovery is a key technique for high-speed optical packet switching(OPS) networks. The locking and unlocking time of the packet clock determines the guard time in the OPS, and therefore affects the network bandwidth utilization. An all-optical packet clock recovery system with ultrafast lockingAll-optical packet clock recovery is a key technique for high-speed optical packet switching(OPS) networks. The locking and unlocking time of the packet clock determines the guard time in the OPS, and therefore affects the network bandwidth utilization. An all-optical packet clock recovery system with ultrafast locking and unlocking time via the self-phase modulation effect of the saturated semiconductor optical amplifier(SOA) and an optical band-pass filter was proposed. The 10 GHz packet clock recovery with locking time of two code-periods and unlocking time of six-code periods is obtained..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 151 (2009)
Pressure Sensing Characteristics of Panda Fiber Gratings
Li Zhizhong, Yang Huayong, Cheng Yusheng, and Hu Yongming
The pressure sensing mode of panda fiber gratings is built using the finite element method and the stress distribution induced by pressure is analyzed. The experimental results show that the peak separation of Panda fiber gratings increases with pressure, and -4.08 pm/MPa the pressure sensitivity along fast axis is strThe pressure sensing mode of panda fiber gratings is built using the finite element method and the stress distribution induced by pressure is analyzed. The experimental results show that the peak separation of Panda fiber gratings increases with pressure, and -4.08 pm/MPa the pressure sensitivity along fast axis is stronger than that -3.5 pm/MPa along slow. The influence of fiber structure on pressure sensing characteristics is studied through theoretical calculation and experimental measurement, and the results show that the pressure sensing coefficients of panda fiber gratings are linear with the square of the ratio of radius to distance of stress applied zone. The contrastive experimental results show that the Panda fiber grating cannot be used to measure thermally-insensitive pressure through testing its peak separation..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 157 (2009)
Image Processing
Salt & Pepper Noise Switching Filter Based On LS-SVR Convolution Mask
Yu Zhongdang, and Wang Longshan
Aiming at the characteristic of salt & pepper noise, the switch salt & pepper noise suppression algorithm for noise points data restoration based on LS-SVR (least square support vector machines regression) is presented. First, the max-min operator is used to differentiate the noise at the filter windows center,Aiming at the characteristic of salt & pepper noise, the switch salt & pepper noise suppression algorithm for noise points data restoration based on LS-SVR (least square support vector machines regression) is presented. First, the max-min operator is used to differentiate the noise at the filter windows center, if the center is not the windows extremum, they will output naturally, otherwise they will be judged as noise and divide windows into center corrupted points and multi-corrupted points. The well data approach ability is utilized to fit the curved surface for windows. It realized efficient restoration of data corrupted and reduced the data points damage for miscarriage of justice as noise. To improve the arithmetic operation speed, it constructed the two type LS-SVR convolution mask based on the filtering strategy and LS-SVR characteristic, training process of LS-SVR is turned into simple weighted summation operation which increased the algorithmic practicability. Experiments show that the proposed algorithm has better detailed protecting ability and better removing noise ability..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 163 (2009)
Research on the Point Spread Function of Microscope Based on the Zernike Polynomials
Tang Yuke, He Xiaohai, and Tao Qingchuan
In the non-blind image restoration of the computational optical sectioning microscopy (COSM), the acquisition of accurate point spread function of the system has a major impact on the quality and the stability of image restoration. There are two ways to access the point spread function in general: numerical calculationIn the non-blind image restoration of the computational optical sectioning microscopy (COSM), the acquisition of accurate point spread function of the system has a major impact on the quality and the stability of image restoration. There are two ways to access the point spread function in general: numerical calculation and physical measurements. Numerical calculation has heavy computational burden and more parameters which always cannot be accurately estimated, hence, it has some limitations in practical application; the point spread function accessed by physical measurements can embody the optical properties of the microscope system most properly, but it has low signal\|to\|noise ratio (SNR), it must be pre-processed before used. A detailed introduction of the principle about how to use the extended Nijboer-Zernike theory (ENZ) to reconstruct the point spread function accessed by physical measurements is given. Experiments proved that this method can rapidly and accurately reconstruct the 3D point spread function of the microscope and raise its SNR..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 169 (2009)
Real-Time Infrared Noise Reduction Based on Anisotropic Diffusion Method
Wang Xianya, Chen Qian, and Gu Guohua
An infrared noise reduction algorithm based on anisotropic partial differential equation is proposed. By combining morphological operations with infrared imaging local features, a new anisotropic coefficient is established. This coefficient gets gradient operator by morphological dilating and eroding, improves the sensAn infrared noise reduction algorithm based on anisotropic partial differential equation is proposed. By combining morphological operations with infrared imaging local features, a new anisotropic coefficient is established. This coefficient gets gradient operator by morphological dilating and eroding, improves the sensibility of Perona-Malik (P-M) gradient, strengthens diffusion in homogeneous area and weakens diffusion in heterogeneous area. The algorithm has run on the EVM-DM642 hardware platform in real time, and experiments indicate the noise is smoothed out effectively, and the image edge is also preserved better..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 176 (2009)
Minimum-Discontinuity Phase Unwrapping Algorithm Based on Edge Detection
Zhang Ting, Lu Yuangang, and Zhang Xuping
A new minimum-discontinuity unwrapping algorithm based on edge detection is proposed to overcome the disadvantage of Flynn′s minimum-discontinuity approach and unwrap the wrapped phase images rapidly and efficiently. In the new algorithm, isolated noisy pixels are excluded from the scanning areas of searching for improA new minimum-discontinuity unwrapping algorithm based on edge detection is proposed to overcome the disadvantage of Flynn′s minimum-discontinuity approach and unwrap the wrapped phase images rapidly and efficiently. In the new algorithm, isolated noisy pixels are excluded from the scanning areas of searching for improving loops firstly, and then the phase′s discontinuous areas within wrapped phase image are detected based on edge detection techniques and taken as the scanning areas. Because the required scanning range is cut down to a large extent by use of edge detection methods, the efficiency of the minimum-discontinuity phase unwrapping algorithm is significantly improved. The principle and implementation steps of the new algorithm are described in detail, and some computer simulation and experimental wrapped phase images are used to verify the effectiveness of the algorithm. Unwrapped results show that the proposed algorithm works perfectly and is more effective than the Flynn′s minimum discontinuity-approach..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 180 (2009)
Imaging Systems
Multispectral Image Acquisition System Based on Liquid Crystal Tunable Filter
Du Lili, Yi Weining, Zhang Dongying, Fang Wei, and Qiao Yanli
In remote sensing, the subdivision and increase of detecting bands require to enhance the acquisition and transmission speed of image. This makes the old wavelength tuning method and interface specification can not meet the need. A new multispectral image acquisition system based on liquid crystal tunable filter (LCTF)In remote sensing, the subdivision and increase of detecting bands require to enhance the acquisition and transmission speed of image. This makes the old wavelength tuning method and interface specification can not meet the need. A new multispectral image acquisition system based on liquid crystal tunable filter (LCTF) is proposed. In this system, LCTF is used to substitute traditional filter wheel. It is electronically tunable and allows for the rapid, accuracy and vibrationless selection of any wavelength in the range of 400～720 nm, and its fastest response time can be up to 50 ms. And the system follows the Camera Link specification and the PCI bus standard, which makes the embedded computer realize real-time control of the wavelength tuning of LCTF, the exposure time setting of the camera and the acquisition and storage of image data by program. The whole system characterized by small volume, low power consumption, high stability and high acquisition speed. The system could work on plane and airship platforms, and it′s suitable for researching in the fields of low altitude remote sensing and environmental monitoring..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 187 (2009)
Numerical Analysis of Dynamic Modulation Transfer Function for High-Resolution Aerial Camera
Qian Yixian, Liang Wei, and Gao Xiaodong
Aerial vibration is a key factor affecting dynamic image quality of high-resolution aerial camera. Base on the theory of optical transfer function, dynamic modulation transfer function (MTF) is obtained by applying the conception that probability density function of motion is equal to point/line spread function of optiAerial vibration is a key factor affecting dynamic image quality of high-resolution aerial camera. Base on the theory of optical transfer function, dynamic modulation transfer function (MTF) is obtained by applying the conception that probability density function of motion is equal to point/line spread function of optical system. The influence of linear motion, sinusoidal vibration and random vibration is developed respectively. With the help of Matlab software, dynamic MTF is simulated, and the drawn conclusion is consistent with the results of the other literatures. This method can be expanded to two-dimensional motion. Vibrational MTF is compared with that under static condition, and the results are consistent with simulation curve with a 30% decrease at the Nyquist frequency. The method can be applied for forecasting and evaluating image quality on aerial camera and other optoelectronic systems, and the results can be used in deconvolution filter to realize image restoration..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 192 (2009)
Three-Dimensional Profilometry Based on Mexican Hat Wavelet Transform
Zhou Xiang, and Zhao Hong
A method handling fringe patterns based on Mexican hat wavelet transform is presented to improve the ability of spatial localization in wavelet transformation profilometry. Mexican hat wavelet is chosen to perform continuous wavelet transform of the fringe pattern after converting original signal into the analytic formA method handling fringe patterns based on Mexican hat wavelet transform is presented to improve the ability of spatial localization in wavelet transformation profilometry. Mexican hat wavelet is chosen to perform continuous wavelet transform of the fringe pattern after converting original signal into the analytic form by Hilbert transform. The phase distribution is recovered from the coefficients on the ridge of the transform and the height distribution is retrieved. The simulated results show Mexican hat wavelet transform method has good performance in spatial localization and high accuracy both in the neighborhood of the height-discontinuous points and in the areas with sharply varying height, and the errors can be reduced by 0.1 rad～0.5 rad. The experiment for the fringe image of a plaster face shows Mexican wavelet transform method has smaller error propagation and higher precision than Morlet wavelet method in the areas with incontinuous or sharply varying height..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 197 (2009)
Instrumentation, Measurement and Metrology
Laser Ultrasonic Measurement System Based on Wireless Communication Technology
Chen Xiao
The laser ultrasonic technology is one of the most important and state-of-the-art non-contact ultrasonic measurement technology. Combined wireless communication technology and laser measurement technology, a novel laser ultrasonic nondestructive measurement system is presented to reduce cables connection between units The laser ultrasonic technology is one of the most important and state-of-the-art non-contact ultrasonic measurement technology. Combined wireless communication technology and laser measurement technology, a novel laser ultrasonic nondestructive measurement system is presented to reduce cables connection between units of the system. The principle and structure of the system are introduced. A NdYAG solid laser is used to excite ultrasound in the specimen and a piezoelectric transducer is used to detect ultrasonic signal. The signal is magnified and digitalized by a system-on-chip MSP430F2274 single chip microcomputer. Then it is transmitted wirelessly via nRF905 chip under the control of microcomputer. The signal is delivered to computer through serial communication interface between single-chip microcomputer AT89S52 on the received terminal and computer under RS-232-C serial communication interface protocol. The pulse signal is then shown, recorded, saved and processed through computer software. The designed system realizes short distance wireless measurement of laser ultrasonic. It has some advantages such as predigested system structure, reliable transmission. It shows great potential for future applications..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 203 (2009)
Research of Intelligent Clothing for Body Temperature Monitoring Based on Distributed Optical Fiber Bragg Grating Sensors
Li Hongqiang, Yu Xiaogang, Miao Changyun, Li Enbang, Xi Jiangtao, Wang Rui, Zhang Cheng, Zhang Meiling, and Liu Liyan
Optical Fiber Bragg Grating (FBG) sensors have received increasing attention in the fields of aeronautic and civil engineering for their superior ability of explosion proof, immunity to electromagnetic interference and high accuracy, especially fitting for measurement applications in harsh environment. A novel integratOptical Fiber Bragg Grating (FBG) sensors have received increasing attention in the fields of aeronautic and civil engineering for their superior ability of explosion proof, immunity to electromagnetic interference and high accuracy, especially fitting for measurement applications in harsh environment. A novel integration of FBG sensors into clothing is becoming an increasingly important segment in electronic textile research. A functioning prototype of such an intelligent biomedical clothing is introduced. It aims at the integration of optical fibers based sensors into functional textiles for extending the capabilities of wearable solutions for body temperature monitoring. According to the laws of human body physiology and heat transmission in fabric, the mechanism of heat transmission between body and clothed FBG sensors was studied and the calculating formula reflecting the heat transfer process between body and clothed FBG sensors was presented. Some details and overview regarding our ongoing efforts for achieving the goals are provided. The experimental results are in good agreement with those obtained by temperature-field simulation. This should favor their use for clinical axillary temperature monitoring..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 208 (2009)
Virtual Optical-Fiber Sagnac Interferometer and Analog-Digital Mixed Demodulation System
Sun Guoxin, and Zhou Kejiang
Demodulation algorithm is a very important part in the Sagnac interferometer system. In the demodulation process of some digital open-loop algorithms, some special phase points will confuse with each other and cause an error output value. Based on the theoretical analysis of special phase points, a virtual optical-fibeDemodulation algorithm is a very important part in the Sagnac interferometer system. In the demodulation process of some digital open-loop algorithms, some special phase points will confuse with each other and cause an error output value. Based on the theoretical analysis of special phase points, a virtual optical-fiber Sagnac interferometer system with integrated circuit chip is designed and implemented. This system can easily solve the problem of special phase point measurement in demodulation system, and judge whether the demodulation system can generates an error in these special phase points. In the experiment, special phase point test is implemented to a digital-analog mixed demodulation system by the proposed. The scale factor of the virtual optical-fiber Sagnac interferometer is 49.9°/V. The nonlinear degree of the scale factor is 0.167%, and the asymmetry degree of the scale factor is 0.088062%. The zero drift of the system is 9.5265°/h..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 213 (2009)
Optical Voltage Transducer Based on Modular Interference in Highly Elliptical-Core Polarization-Maintaining Fiber
Liu Feng, Bi Weihong, and Guo Xuan
An optical voltage transducer (OVT) for the electric power system based on modular interference in dual-mode highly elliptical-core polarization maintenance fiber (E-core PMF) is designed, and the temperature and environmental perturbation can be compensated automatically. A quartz crystal cylinder wrapped with highly An optical voltage transducer (OVT) for the electric power system based on modular interference in dual-mode highly elliptical-core polarization maintenance fiber (E-core PMF) is designed, and the temperature and environmental perturbation can be compensated automatically. A quartz crystal cylinder wrapped with highly elliptical-core fiber plays the role of voltage sensor head. The two interference output lobes′ intensity from the E-core PMF is modulated with the converse piezoelectric effect of quartz crystal. A PZT wrapped with E-core PMF at ground potential serves as the static modular phase difference control and temperature compensation unit. The experimental results show that the measurement precision of is 0.5% near by rated voltage, and the OVT has a good linearity when measured voltage is greater than 10 kV..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 219 (2009)
Multiple-Beam Phase Shifting Algorithm Based on Least-Squares Iteration
Xu Jiancheng, Chen Jianping, Xu Qiao, and Chai Liqun
High-order harmonics and phase-shift miscalibration are the two main systematic error sources that affect the accuracy of interferometry. To deal with these problems simultaneously, a multiple-beam phase shifting algorithm based on least-squares iteration is proposed. The proposed algorithm decomposes multiple-beam friHigh-order harmonics and phase-shift miscalibration are the two main systematic error sources that affect the accuracy of interferometry. To deal with these problems simultaneously, a multiple-beam phase shifting algorithm based on least-squares iteration is proposed. The proposed algorithm decomposes multiple-beam fringes into fundamental wave and high-order harmonics by using the Fourier series expansion. Only five frames of multiple-bean interference fringes with random phase shifts are required to accurately determine the phase distribution and phase shifts. Simulations show that the proposed algorithm reaches the error less than 0.005 (peak-valley value, PV) and 0.003 rad (root-mean-square, RMS) with 10 iterations when the reflection coefficient and the RMS of random phase shifts are less than 0.6 and 1 respectively. It also shows that the proposed algorithm exhibits higher precision than the traditional five-bucket algorithm. Experiment demonstrates that the proposed algorithm is valid and superior to two-beam phase shifting algorithm..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 224 (2009)
Materials
First-Principles Calculation of Electronic Structure and Optical Properties of Mg2Si with Doping
Chen Qian, Xie Quan, Yang Chuanghua, and Zhao Fengjuan
The energy band structures, density of states and optical properties of Mg2Si and Ag , Al-doped Mg2Si have been calculated systemically by first-principles pseudopotential method based on density functional theory (DFT). The calculated results show that Mg2Si is an indirect semiconductor with the band gap of 0.2994 eV,The energy band structures, density of states and optical properties of Mg2Si and Ag , Al-doped Mg2Si have been calculated systemically by first-principles pseudopotential method based on density functional theory (DFT). The calculated results show that Mg2Si is an indirect semiconductor with the band gap of 0.2994 eV, the valence bands of Mg2Si are composed of Si 3p, Mg 3s, 3p, the conduction bands are mainly composed of Mg 3s, 3p as well as Si 3p, the static dielectric function is 18.89, and the refractive index is 4.3460. Ag-doped Mg2Si sample is p-type, the valence bands are composed of Si 3p, Mg 3s, 3p and Ag 3p, 4d and 5s, static dielectric function is 11.01, and the refractive index is 3.3175 after doping Ag. Al-doped Mg2Si sample is n-type, the conduction bands are composed of Mg 3s, 3p, Si 3p, and Al 3p, the static dielectric function is 87.03, and the refractive index is 9.3289 after doping Al. The electronic structure of Mg2Si can be modulated effectively by doping. The results offer theoretical data for the design and application of optoelectronic materials of Mg2Si..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 229 (2009)
Crystal Structure and Photoelectric Properties of 3-Phenyl-6-(4-Methylphenyl)-1,2,4-Triazolo[4,3-b]-1,2,4-Triazine
Li Huixue, Xu Hengxia, Li Zhifeng, Wang Xiaofeng, Dong Xiaoning, Yuan Kun, Zhu Yuancheng, and Xiao Tai
In order to explore the photoelectric properties of the fuse ring compound 3- phenyl-6-(4-methylphenyl)- 1,2,4-triazolo [4,3-b]- 1,2,4-triazine, the compound crystal structure had been computed by Gaussian program, its properties were studied with density functional theory B3LYP method using 6-31G(d) basis set, and theIn order to explore the photoelectric properties of the fuse ring compound 3- phenyl-6-(4-methylphenyl)- 1,2,4-triazolo [4,3-b]- 1,2,4-triazine, the compound crystal structure had been computed by Gaussian program, its properties were studied with density functional theory B3LYP method using 6-31G(d) basis set, and the stably geometric configuration and bond length,bond angle are obtained and accorded with the experimental value. The properties of the title compounds attaching different substituent to 6-position phenyl have been discussed through the transfer of electric charge, energy level of the frontier molecular orbit and the emission spectrum and so on.The emission wavelength of the compounds attaching different substituent is in 512 ～521 nm, and the photoelectric properties of the compounds with different substituent were analyzed. Different substituent operates on the related compound by inductive and conjugative effect,and meanwhile the properties were affected by altering transferred electric charge number.These fuse ring compounds can be used as photoelectric materials based on computed result..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 236 (2009)
Angle-Dependent EM Scattering Analysis of Special Photonic Crystal and Its Application
He Xiaoxiang, and Li Hao
The angle-dependent characteristic of electromagnetic (EM) scattering from photonic crystal with the microstructure of morpho butterfly′s wing is investigated. The optical scattering properties are analyzed with the simplified model for surface microstructure of morpho butterfly′s wing and finite difference time domainThe angle-dependent characteristic of electromagnetic (EM) scattering from photonic crystal with the microstructure of morpho butterfly′s wing is investigated. The optical scattering properties are analyzed with the simplified model for surface microstructure of morpho butterfly′s wing and finite difference time domain (FDTD) method. Furthermore, the influence of structural parameters on angle-dependent characteristic is studied. The reasonable explanation is presented for the angle-dependent electromagnetic scattering mechanism and its application in the stealth design of military targets are also discussed..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 256 (2009)
Optical Design and Fabrication
Design of Multi-Wavelength Cascaded Raman Fiber Lasers
Qin Zujun, Zhou Xiaojun, Wu Haocheng, and Zou Zili
A novel design algorithm for the steady-state coupled power equations describing stimulated Raman scattering in Multi-wavelength cascaded Raman fiber lasers has been proposed. By taking the advantage of genetic algorithm and shooting method, a few elite individuals with the best fitness on each generation are chosen toA novel design algorithm for the steady-state coupled power equations describing stimulated Raman scattering in Multi-wavelength cascaded Raman fiber lasers has been proposed. By taking the advantage of genetic algorithm and shooting method, a few elite individuals with the best fitness on each generation are chosen to implement several shootings to accelerate theirs converging. As an example, the output characteristics of an all-fiber three-wavelength (1427 nm, 1455 nm, and 1480 nm) Raman fiber laser with 500 meters P2O5-doped fiber as gain medium and fiber Bragg gratings as resonators has been analyzed with the algorithm. The results show that the total output power linearly depends on the pump power approximately with a slope efficiency of ～51%; the slop efficiency of longer wavelengths is larger than that of the shorter wavelengths due to the longer wavelengths gain additional power at the expense of the power of the shorter wavelengths..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 244 (2009)
High-Sensitivity Fiber Bragg Grating Temperature Sensor at High Temperature
Li Kuo, Zhou Zhenan, Liu Aichun, and Wang Xiuying
The durable strain of fiber Bragg grating (FBG) is used to improve the sensitivities of FBG temperature sensors at high temperature. When a sensor is manufactured at room temperature, its FBG is given a pre-relaxing length according to the temperature to measure. Once the temperature rises over the given value, its FBGThe durable strain of fiber Bragg grating (FBG) is used to improve the sensitivities of FBG temperature sensors at high temperature. When a sensor is manufactured at room temperature, its FBG is given a pre-relaxing length according to the temperature to measure. Once the temperature rises over the given value, its FBG starts to be stretched and to work with high sensitivity. The relationship between the pre-relaxing length and the working temperature is analyzed. In experiments, when the pre-relaxing lengths are 0.2 mm, 0.5 mm, 0.6 mm, the working temperatures is raised by 25 ℃, 50 ℃, 61 ℃, respectively, and the sensitivities are almost the same (675 pm/℃). The experimental results agree well with the theoretical analyses..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 249 (2009)
Improvement for Extraction Efficiency of Vertical GaN-Based LED on Si Substrate by Photo-Enhanced Wet Etching
Zhou Yinhua, Tang Yingwen, Rao Jianping, and Jiang Fengyi
The surface of n-GaN is fabricated by photo-enhanced wet etching with the etchant of 0.1 M K2S2O8＋KOH and the illumination of Xe ultraviolet light. The n-GaN with an electrode on its surface is etched. Under the same etching condition, n-GaN with an electrode on its surface shows a higher etching rate but a lower root-The surface of n-GaN is fabricated by photo-enhanced wet etching with the etchant of 0.1 M K2S2O8＋KOH and the illumination of Xe ultraviolet light. The n-GaN with an electrode on its surface is etched. Under the same etching condition, n-GaN with an electrode on its surface shows a higher etching rate but a lower root-mean-error(RMS) compared with n-GaN without an electrode. After etching, the surface of n-GaN is covered by hexagonal cones. Output power of the LED is improved by 88.5% after etching with 20 mA current..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 252 (2009)
Physical Optics
Multiple Reflections and Reshaping Effect of Finite-Sized Light Beams in Thin Dielectric Slab Configuration
Zhu Qibiao, Chen Xi, and Li Chunfang
The physical mechanism of the anomalous lateral displacement of the transmitted finite-sized light beam in a thin dielectric slab configuration is investigated from the view point of the interference between multiple light beams, due to the multiple reflections. The physical restriction, which agrees the mathematical cThe physical mechanism of the anomalous lateral displacement of the transmitted finite-sized light beam in a thin dielectric slab configuration is investigated from the view point of the interference between multiple light beams, due to the multiple reflections. The physical restriction, which agrees the mathematical condition of stationary phase approach, is advanced. Numerical stimulation shows that the anomalous lateral displacement is produced by the reshaping of the transmitted components undergoing different phase shifts due to the multiple reflections inside the slab. From the view point of a beam as a whole, the lateral displacement can be understood by the fact that the entire transmitted beam is the result of reshaping of the multiply transmitted beams..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 262 (2009)
Thin Films
All-Optical Poling for Two Kinds of Host-Guest Adulterant Azo Compound Thin Films
Li Yun, Wang Wenjun, Gao Xuexi, Liu Yunlong, Zhang Bingyuan, and Li Hui
Two kinds of azo compound host-guest adulterant thin films were prepared, then all-optical poling was made and their second-order nonlinear optical characteristics were studied by UV-visual spectra and second-harmonic generation. The experimental results show that the second-order nonlinear optical coefficient d33of 4′Two kinds of azo compound host-guest adulterant thin films were prepared, then all-optical poling was made and their second-order nonlinear optical characteristics were studied by UV-visual spectra and second-harmonic generation. The experimental results show that the second-order nonlinear optical coefficient d33of 4′-Nitro-4-dimethylaminoazobenzene was determined to be 6.89×10-1 pm/V, and that of 4′-Iodo-4-dimethylaminoazobenzene is 7.77×10-2 pm/V. In addition, the two kinds of thin films show different second-harmonic generation (SHG) dependence on the thickness and relaxation after saturation. In therory, these phenomena could be explained by that the different substituen result in different molecular dipole property and interaction between azo molecule and host materials..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 29, Issue 1, 6 (2009)
The Refractive Index Change of Ferrofluid Film Under External Magnetic Field
Chen Shanfei, Wang Zhengliang, and Lu Zhangxian
The ferrofluid film(several micrometers thick), located between two glass plates, was placed vertically in the uniform magnetic field produced by the Helmholtz coil. Measurement of the refractive index of the ferrofluid film under different magnetic field intensities with Michelson interferometer by contrast measuring The ferrofluid film(several micrometers thick), located between two glass plates, was placed vertically in the uniform magnetic field produced by the Helmholtz coil. Measurement of the refractive index of the ferrofluid film under different magnetic field intensities with Michelson interferometer by contrast measuring method, shows that the refractive index changes with the variation of the external magnetic field intensity. This phenomenon is explained by the modification of the size of ferrofluid particles under external magnetic field, which changes the ratio of dimension of the chain of magnetic particles to incident wavelength, thus altering the refractive index of the magnetic fluid. Based on this, the relation between the refractive index and external magnetic field intensity is established, which will provide a new technique for the development of new magneto-optical devices for magnetic field measurement, optical valves and so on..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 273 (2009)
Optical Properties of Cu-Co Alloy Nanowire Arrays in Porous Alumina Template
Zheng Mengmeng, Wu Fuquan, Liu Zaiguo, Zhang Lichun, Li Qingshan, and Tian Jianxiang
Highly ordered porous anodic aluminum oxide (PAA) membranes were prepared by electrochemical method. By alternating current electrodepositing, Cu-Co alloy nanowire arrays were fabricated in the micro column-shaped holes of porous alumina template in a mixed electrolyte of CuSO4 and CoSO4. The morphology and microstructHighly ordered porous anodic aluminum oxide (PAA) membranes were prepared by electrochemical method. By alternating current electrodepositing, Cu-Co alloy nanowire arrays were fabricated in the micro column-shaped holes of porous alumina template in a mixed electrolyte of CuSO4 and CoSO4. The morphology and microstructures of PAA and nanowire arrays were characterized by XRD and SEM. The results show that the surface of Cu-Co nanowire arrays is uniform and regular with a preferred crystal face (111) during growing. And the transmission and polarization spectrum indicate that the sample has good transmittance and extinction ratio. Cu-Co alloy can change some characteristics of the simple metal, and for example, CuCo/PAA has better extinction ratio (30 dB) in near infrared waveband than Cu/Al2O3 (17 dB)..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 277 (2009)
Vision, Color, and Visual Optics
A Novel Measurement Method of Hiding Power for Pigmented Material Based on Gray Level Substrate
Wang Hua, Xu Haisong, Jim Nobbs, and M. Ronnier Luo
The general method measures hiding power of pigmented material based on varying layer thickness. A new measuring technique was developed by varying the substrate pattern and using the substrate with different gray levels to improve the efficiency and accuracy of the hiding power measurement. Considering the propagationThe general method measures hiding power of pigmented material based on varying layer thickness. A new measuring technique was developed by varying the substrate pattern and using the substrate with different gray levels to improve the efficiency and accuracy of the hiding power measurement. Considering the propagation of light after incidence in the layer according to the phenomenological theory, a mathematical model was proposed to simulate the covering ability of the pigment to measure its hiding power based on the systematic analysis of the CIELAB colour differences for the samples before and after painting on the specially designed substrate. The experimental comparison with the existent methods, including Deutsches Institute fur Normung(DIN), American Society for Testing and Materials(ASTM) and spectral evaluation methods, shows that the proposed technique can measure the hiding power accurately and rapidly, with the relative accuracy of 01 %～11 % compared with the referenced results from DIN method. This new method outperforms ASTM and spectral evaluation methods for non-coloured pigment and colourful pigment as well..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 1, 281 (2009)
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