Contents
2009
Volume: 29 Issue 8
57 Article(s)
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Atmospheric Optics and Oceanic Optics
Spectrum Characteristic of Atmospheric Scintillation in Simulating Convective Boundary Layer
Lu Chao, Luo Tao, Wu Xuping, Sun Jianning, and Yuan Renmin
The boundary layer is the transition zone between the surface and free atmosphere. Because of its high level it is difficult to detect the refined structure of the boundary's top layer extensively. Generation and evolution of the atmospheric convective layer were simulated in laboratory convective water tank with tThe boundary layer is the transition zone between the surface and free atmosphere. Because of its high level it is difficult to detect the refined structure of the boundary's top layer extensively. Generation and evolution of the atmospheric convective layer were simulated in laboratory convective water tank with the dimension of 150 cm×150 cm×60 cm. When the collision light beam propagated through the simulated atmospheric convective boundary layer, facula image data could be obtained which was used for spectral analysis. Based on the theory of light wave propagation in turbulent media, the scaling exponents could be given by the method of determining dimensionless interzone. It is found that the scaling exponents in the mixed layer are -8/3 under the condition of the homogeneous land surface, which is the classic value of the homogeneous turbulence. However, the scaling exponents highly depart from -8/3 in the beginning of experiments and in the end they are also close to -8/3 because of the vigorous convection.The average scaling exponents in the entrainment zone have relationships with the convective Richardson number. It is also found that the characteristics of the scaling exponent profile are consistent with the contour lines of heat flux profile and normalized light intensity variation profile..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2033 (2009)
Using MODIS Image to Retrieve Aerosol Optical Characteristic Over Coast of China
Ma Jinji, Qiao Yanli, Yang Shizhi, and Cui Zhifeng
Large area of turbid water body and aerosol with high absorption are the main characters of the offshore coast of our country. A new algorithm is developed to retrieve aerosol optical characteristic over coast waters. Based on several look up tables (LUT) and MODIS image of the clear water with ground surface in the clLarge area of turbid water body and aerosol with high absorption are the main characters of the offshore coast of our country. A new algorithm is developed to retrieve aerosol optical characteristic over coast waters. Based on several look up tables (LUT) and MODIS image of the clear water with ground surface in the clear sky, the model I uses the interpolation method to retrieve the aerosol optical characteristic over the turbid waters. Preliminary validation results comparing with AERONET data in Dongshan island show that the algorithm has good accuracy and promising potential. By using the algorithm, the preliminary retrieval of aerosols are carried out for MODIS data of ocean surface in Bohai bay area. The new algorithms would be useful in studying the atmospheric correction models of HY and FY satellites. And it can directly use CMODIS data of FY-3 to retrieve accurately aerosol optical characteristic and water color of coast zone..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2039 (2009)
Study and Simulation of Air Influences on Laser Pulse Transmission Delay Time
Han Cheng, Bai Baoxing, Yang Huamin, Tong Shoufeng, Fan Jingtao, Chen Chunyi, and Yu Lintao
The characteristics of air scattering and absorption are analyzed, and laser pulse delay time domino effect caused by air scattering is studied. Laser pulse transmission delay time caused the air channel, on the conditions of different visibilities, different transmission distances, different scattering coefficients anThe characteristics of air scattering and absorption are analyzed, and laser pulse delay time domino effect caused by air scattering is studied. Laser pulse transmission delay time caused the air channel, on the conditions of different visibilities, different transmission distances, different scattering coefficients and one way scattering albedo, is quantitatively analyzed. It can provide theory basis for emendation of detection error.The simulation result show that the path delay caused air scattering is greater and laser pulse transmission delay time is longer, when the air channel scattering is more severe and air scattering coefficient is not changed. while the air absorption is more obvious, the laser pulse transmission delay time is less..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2046 (2009)
New Calibration Method for Fernald Forward Inversion of Airborne Lidar Signals
Ji Chengli, and Zhou Jun
For Fernald forward inversion of airborne lidar signals require an accurate calibrating value, a new calibration method was put forward. Using lidar equation, atmospheric backscattering signal profiles, as well as a known aerosol backscattering coefficient profile, the calibrating values of other signal profiles are deFor Fernald forward inversion of airborne lidar signals require an accurate calibrating value, a new calibration method was put forward. Using lidar equation, atmospheric backscattering signal profiles, as well as a known aerosol backscattering coefficient profile, the calibrating values of other signal profiles are determined. Simulation and observation results indicate its feasibility. The aerosol backscattering coefficient profiles inversed by the calibrating value, which is determined by the calibration method, are relatively veracious, and the relative error of aerosol backscattering coefficient caused by the method is less than 20%. It is considered that the calibration method can be applied to Fernald forward inversion of airborne lidar signals..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2051 (2009)
Analysis on Influencing Factors of Q Value and its Parametrization
Huang Changchun, Li Yunmei, Sun Deyong, and Le Chengfeng
The measurement of bidirectional function Q is difficult in the case of Ⅱ waters, due to their high-scattering properties, and the HYDROLIGHT is used to simulate the Q value at the 440 nm wavelength with observation angles at the solar nadir angle. Then the effects of environment and water optical characters on Q valueThe measurement of bidirectional function Q is difficult in the case of Ⅱ waters, due to their high-scattering properties, and the HYDROLIGHT is used to simulate the Q value at the 440 nm wavelength with observation angles at the solar nadir angle. Then the effects of environment and water optical characters on Q value are analyzed. Results indicate that in shore and inland lakes of high-scattering waters, the influence of wind speed, scattering phase function, and other factors on the Q value decreases due to the increase in scattering time. So single albedo(W0) and solar zenith angle (θ) become the main influencing factors. With increasing depth, the effect of conditions such as boundary and incident light on the bidirectional function Q value becomes weaker and weaker until the effect disappears completely. In this case the Q value becomes the internal optical parameter that bears no relationship with the conditions of boundary and incident light. The main influencing factors W0, θ, and diffuse attenuation coefficient KLu of upwelling radiance are used to parameterize the Q value that can be expressed in two ways..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2059 (2009)
Fiber Optics and Optical Communications
Basic Optical-Mechanical Transformation Theoretical Equation for FBG Strain Sensors
Wu Yonghong, Qu Wenun, Shao Changjiang, Zhou Wei, and Cai Haiweng
Based on Ansari’s strain transferring analytical model for fiber optic sensors and basic theories in elastic mechanics, a universal basic optical-mechanical transformation theoretical equation which is the base for standarzied design and precision analysis for embedded fiber Bragg grating (FBG) strain sensors is establBased on Ansari’s strain transferring analytical model for fiber optic sensors and basic theories in elastic mechanics, a universal basic optical-mechanical transformation theoretical equation which is the base for standarzied design and precision analysis for embedded fiber Bragg grating (FBG) strain sensors is established. In course of establishing the equation, the axial mechanically coupling mechanisms within sensor complex and with sensed environments are reflected, each boundary condition and displacement coordination condition for strain transferring analytical mode are considered, and all sensor geometrical parameters are taken into account. Experimental study on a sensor sample has validated the rough reliability of proposed theoretical equation..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2067 (2009)
Fiber Grating Filter Based on One Channel DC-Free Design of Apodized Sampling Grating Filter
Chen Peng, Wang Rong, Pu Tao, Lu Lin, Fang Tao, Zhu Yinxun, and Zheng Jilin
The chirp of sampling period is applied for balancing one channel’s DC component of apodized sampling grating. This method has the advantages that wavelength design is flexible and unrestricted to phase mask period, and just a single exposure and a sub-micrometer precision are needed. Maximum reflectivity model and refThe chirp of sampling period is applied for balancing one channel’s DC component of apodized sampling grating. This method has the advantages that wavelength design is flexible and unrestricted to phase mask period, and just a single exposure and a sub-micrometer precision are needed. Maximum reflectivity model and reflectivity notch bandwidth model of uniform grating are used to obtain the relation between UV photo-induced index increment of single mode hydrogen loading fiber and its dose. Based on this method, cosine apodized grating filters with central wavelength of 1549.84 nm, 3 dB bandwidth of 75 pm and 55 pm respectively, are fabricated. The results indicate that experimental and simulation data are coincided well, F-P resonance in high frequency side and the unbalance of -1st reflection and transmittance spectrum are totally eliminated, and the suppression of reflection sidelobes is beyond 20 dB..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2071 (2009)
Design and Analysis for Novel Asymmetric Y-Branch Waveguides
Tang Xionggui, Liao Jinkun, Li Heping, Lu Rongguo, and Liu Yongzhi
Asymmetric Y-branch waveguides are important passive components for unequal power splitting, and are widely used in integrated optical circuit. Based on total internal reflection, novel asymmetric Y-branch waveguide is proposed, in which there is little horizontal offset distance between the branch point of the two braAsymmetric Y-branch waveguides are important passive components for unequal power splitting, and are widely used in integrated optical circuit. Based on total internal reflection, novel asymmetric Y-branch waveguide is proposed, in which there is little horizontal offset distance between the branch point of the two branch waveguides and the axe of the input waveguide, and the branching ratio can be controlled by changing offset distance. Its optical characteristic is thoroughly investigated by using finite difference beam propagation method(FD-BPM). The simulated results show that arbitrary branching ratio can be realized, and the optical power loss is only 0.417 dB while the branching angle is 14°. This novel asymmetric Y-branch waveguides with low polarization dependence can be easily fabricated, and have more advantages than previously designed ones while being used in integrated optical devices..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2077 (2009)
The Experimental Research on 10 Gb/s all-Optical Half-Subtracter by Using Semiconductor Optical Amplifier
Han Bingchen, Yu Jinlong, Zhang Litai, Wang Wenrui, Jiang Yang, Zhang Aixu, and Yang Enze
A novel all-optical half-subtracter combination logic scheme is demonstrated, based on two semiconductor optical amplifiers (SOA) and three narrow optical bandpass filters (NOBPF). By utilizing four-wave mixing (FWM), cross-gain modulation (XGM) in the SOA and through adjusting narrow optical bandpass filter central waA novel all-optical half-subtracter combination logic scheme is demonstrated, based on two semiconductor optical amplifiers (SOA) and three narrow optical bandpass filters (NOBPF). By utilizing four-wave mixing (FWM), cross-gain modulation (XGM) in the SOA and through adjusting narrow optical bandpass filter central wavelength, the first SOA generates ·B logic and provides borrow bit of half-subtracter, simultaneously the SOA generates XNOR logic; the second SOA generates NOT logic, two cascaded SOAs engender XOR logic and provides difference bit of half-subtracter. In the experiment, all-optical half-subtraction Boolean calculation is achieved between 10 Gb/s PRBS signals..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2082 (2009)
Two-User 2.5 Gb/s 100 km Optical Code Division Multiple Access Transmission Experiment
Lu Lin, Pu Tao, Yu Luocheng, Zheng Jilin, Fang Tao, and Li Yuquan
There are three key modules in coherent optical code division multiple access (OCDMA) system: source of ultra-short optical pulse, en/decoder and receiver. Two-user 2.5 Gb/s OCDMA experiment is shown to achieve 100 km transmission using single-band application between gain switch laser diode and 63-chip equivalent phasThere are three key modules in coherent optical code division multiple access (OCDMA) system: source of ultra-short optical pulse, en/decoder and receiver. Two-user 2.5 Gb/s OCDMA experiment is shown to achieve 100 km transmission using single-band application between gain switch laser diode and 63-chip equivalent phase shift superstructured fiber Bragg grating (EPS-SSFBG) phase en/decoder, and threshold adjustable receiver with broadband decision. Relations between bit error rate (BER) and decision level and time are observed in the experiment, error-free transmission is achieved in the range of 10 ps decision time and 17% decision level..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2087 (2009)
Generation of Multi-Wavelength Optical Pulses and Electrical Clock Signal Utilizing Optoelectronic Oscillator with Single Light Source
Jiang Yang, Yu Jinlong, Zhang Litai, Wu Bo, Zhang Li, and Yang Enze
A scheme of generating multi-wavelength optical pulses based single light source optoelectronic oscillator (OEO) is proposed. By utilizing a directly modulated laser and spectral slicing technique, multi-wavelength optical pulses and electrical clock signal are generated in an OEO cavity. Multi-wavelength channels formA scheme of generating multi-wavelength optical pulses based single light source optoelectronic oscillator (OEO) is proposed. By utilizing a directly modulated laser and spectral slicing technique, multi-wavelength optical pulses and electrical clock signal are generated in an OEO cavity. Multi-wavelength channels form a multi-loop configuration naturally, which can effectively suppress sidemodes. In demonstration, 10-ps-wide optical pulses at 5 GHz repetition rate are generated with 1 ps timing jitter, which can be arranged in 20 GHz (4×5 GHz) OTDM and time-/wavelength-interleaved optical pulse stream at different nodes. Along with the optical outputs, 5 GHz electrical signal with low phase noise (-113 dBc/Hz at 10 kHz offset from the carrier) and -100 dBc/Hz spurious modes suppression is also obtained..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2093 (2009)
Coupling Characteristics of Spatial X-Crossing Waveguides
Sun Yiling, Jiang Xiaoqing, Yang Jianyi, and Wang Minghua
Spatial X-crossing waveguides consist of two vertically stacked waveguides crossed in an X type shape. These kinds of devices can be served as vertical couplers, vertical coupler filters, vertical optical switches and optical add/drop multiplexers. Based on the perturbation theory, a technique named equivalent field maSpatial X-crossing waveguides consist of two vertically stacked waveguides crossed in an X type shape. These kinds of devices can be served as vertical couplers, vertical coupler filters, vertical optical switches and optical add/drop multiplexers. Based on the perturbation theory, a technique named equivalent field matching method (EFMM) is presented for analyzing the coupling characteristics of spatial X-crossing waveguides. The field profile of the rectangular waveguide is treated as a perturbation to radially symmetric fiber, and more accurate calculation of the coupling lengths of the spatial X-crossing waveguides is presented with the effect of corner regions taken into account. And the three-dimensional full-vector beam propagation method (3D-BPM) is used to verify these analytical results. Comparison of the coupling lengths obtained by the 3D-BPM and EFMM shows that the maximum relative error is 1.2%, and the average relative error is 0.9%. Results show that this proposed method is more convenient compared with other numerical methods. The equivalent field matching method is extremely useful in the accurate design of three-dimensional integrated optical devices based on spatial X-crossing waveguides..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2099 (2009)
Holography
Object Wave Reconstruction by Using Single in-Line Digital Fresnel Hologram
Wang Bo, and Li Chongguang
In the study of digital holography, an in-line optical arrangement is often made to record holograms so as to exploit the finite space band-width product of CCD sensor sufficiently. However, when an in-line hologram is used to reconstruct original object wave, its conjugate wave will coexist in the diffracted field. SeIn the study of digital holography, an in-line optical arrangement is often made to record holograms so as to exploit the finite space band-width product of CCD sensor sufficiently. However, when an in-line hologram is used to reconstruct original object wave, its conjugate wave will coexist in the diffracted field. Separating desired component from conjugate component is very difficult. The effective elimination of conjugate image during numerical reconstruction through in-line hologram has been a crucial technique, which facilitates and promotes the application of digital holography. Based on Fresnel diffraction calculation and its inverse calculation, an iterative algorithm to reconstruct object wave from in-line digital hologram is presented. According to this method, conjugate component can be removed from reconstruction to get original object wave by utilizing the difference of their diffractive characteristics. The object wave can be reconstructed numerically through single in-line hologram. The computer simulation demonstrates that the method proposed here is feasible and easy to operate..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2104 (2009)
Digital Reconstruction of Fresnel Hologram with a Ridge of Gabor Wavelet Transform
Weng Jiawen, Zhong Jingang, and Hu Cuiying
A digital reconstruction method of Fresnel hologram with a ridge of Gabor wavelet transform is described. Applied the Gabor wavelet transform to the digital holography, the object wave can be numerical reconstructed without the spatial filtering. The Gabor wavelet transform and the ridge of the wavelet transform are inA digital reconstruction method of Fresnel hologram with a ridge of Gabor wavelet transform is described. Applied the Gabor wavelet transform to the digital holography, the object wave can be numerical reconstructed without the spatial filtering. The Gabor wavelet transform and the ridge of the wavelet transform are introduced. It proves that by abstracting the wavelet coefficients at the ridge of the wavelet transform of the hologram, the intensity and the phase of the object wave corresponding to the +1-order spectrum at the hologram plane are obtained, at the same time the effect of the zero-order diffraction image and the twin image is eliminated. Multiplying the wavelet coefficients at the ridge by an ideal wave corresponding to a replica of the reference wave and propagating for the corresponding propagation distance, the reconstructed wave at the image plane is reconstructed, and a clear image is obtained. The results of a simulated phase object and an experiment show that the method is effective..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2109 (2009)
Image Processing
The Two-dimensional Otsu Thresholding Based on Fish-swarm Algorithm
Pan Zhe, and Wu Yiquan
Thresholding is a simple and efficient technique for image segmentation in digital image processing. In this paper, the fish-swarm algorithm of swarm intelligence is used in image threshoding, and the two-dimensional Otsu thresholding algorithm based on the fish-swarm algorithm is proposed. Numerous experiments show thThresholding is a simple and efficient technique for image segmentation in digital image processing. In this paper, the fish-swarm algorithm of swarm intelligence is used in image threshoding, and the two-dimensional Otsu thresholding algorithm based on the fish-swarm algorithm is proposed. Numerous experiments show that this algorithm could select the best threshold accurately. In experiments, the threshold, mean and variance from running the two-dimensional Otsu thresholding based on fish-swarm algorithm and single genetic algorithm, as well as the elitist strategy genetic algorithm ten times independently are compared. Moreover, the convergence curves are selected as the evaluation of the algorithm complexity. Experiment results show that this method not only can segment the image more accurately, but also has faster convergent speed..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2115 (2009)
Spectral-Based Color Separation for Multi-Spectral Images
Wang Ying, Zeng Ping, Wang Yifeng, and Luo Xuemei
To reproduce multi-spectral images on a printer, a new spectral-based color separation method using the nonlinear optimization technology was presented, which could improve spectral and the colorimetric precision simultaneously. Based on the color principles of printer systems and the Neugebauer model, the effect of spTo reproduce multi-spectral images on a printer, a new spectral-based color separation method using the nonlinear optimization technology was presented, which could improve spectral and the colorimetric precision simultaneously. Based on the color principles of printer systems and the Neugebauer model, the effect of spectral and colorimetric characteristics of images on printing output was analyzed. This led to the conclusion that spectral and colorimetric errors were both important for printed images. For this reason, the spectral error and colorimetric error objective functions were designed firstly, one presenting the colorimetric precision of the printed images and another for spectral precision. Furthermore, the effective area coverage of the printer primary inks was limited according to the actual printing process. Finally the nonlinear optimization method was used, by which the spectral reflectance of the multi-spectral images could be transformed to the effective area coverage of the inks and the color separation was realized. Experiments show that the proposed method improves the spectral and colorimetric precision simultaneously. The output spectral precision is about 3 to 10 times higher than that of the regressive method only based on the spectral error..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2122 (2009)
Novel Matching Filter Design and its Application on Dim Point Target Detection in Infrared Image
Zhu Jinbiao, and Li Jianxun
The characteristics of dim point target during infrared image acquisition is analyzed, aiming at detecting them under a very low signal-to-noise ratio (SNR) and strong background interferences. Based on spatial distributions of targets, background and noise, a novel spatial matching filter is proposed to raise SNR fromThe characteristics of dim point target during infrared image acquisition is analyzed, aiming at detecting them under a very low signal-to-noise ratio (SNR) and strong background interferences. Based on spatial distributions of targets, background and noise, a novel spatial matching filter is proposed to raise SNR from original low level. This spatial matching filter is optimized from 1D version considering the diffraction effects of targets. Then a novel morphology is presented to reduce background and enhance target saliency. A threshold selection algorithm is adopted to extract dim point targets adaptively. In all three stages, diffraction effects of targets and intensity difference of targets with background are taken into account to improve detection performance. Experimental results prove that under a low SNR (≤2), the successful detection rate of proposed method is over 95% with 10-5 false detection rate..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2128 (2009)
Fourier-Curvelet Transform Combined Image Restoration
Deng Chengzhi, Wang Shengqian, and Cao Hanqiang
The ill-posed inverse problem of image restoration is studied. Firstly, the mathematical model and ill-posed property of image restoration are analyzed, and a Fourier-curvelet combined image restoration (ForCurIR) algorithm is proposed. ForCurIR algorithm exploits the Fourier transform’s sparse representation of the coThe ill-posed inverse problem of image restoration is studied. Firstly, the mathematical model and ill-posed property of image restoration are analyzed, and a Fourier-curvelet combined image restoration (ForCurIR) algorithm is proposed. ForCurIR algorithm exploits the Fourier transform’s sparse representation of the colored noise and curvelet transform’s sparse representation piecewise smooth images. The problem of image restoration is turned into constrained deconvolution in Fourier domain and constrained denoising in curvelet domain. Deconvolution and noise suppressing are performed via shrinkage both in the Fourier and curvelet domain. Experimental results demonstrate that ForCurIR algorithm can properly retrieve various kinds of image edges, and the signal-to-noise ratio (SNR) and visual quality of the restored images are improved significantly..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2134 (2009)
Noise Reduction with Wavelet Transform in Optical Coherence Tomographic Images
Deng Juxiang, and Liang Yanmei
Noise in optical coherence tomographic (OCT) imaging degrades the quality of images, so improving image’s signal-to-noise ratio (SNR) is a focal problem in the development of OCT system. According to the distribution characteristics of signal and image noise collected by OCT system, a wavelet denoising method with a biNoise in optical coherence tomographic (OCT) imaging degrades the quality of images, so improving image’s signal-to-noise ratio (SNR) is a focal problem in the development of OCT system. According to the distribution characteristics of signal and image noise collected by OCT system, a wavelet denoising method with a bivariate shrinkage function is improved, by increasing the radius of deadzone in a subband which includes more noise coefficient, to reduce noise. Some estimation parameters, such as contrast-to-noise ratio (CNR), SNR and edge preservation parameter, are used to estimate the improved effect of the image. The results show that it can reduce noise effectively and preserve edge information..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2138 (2009)
Influence of Noise to Phase Diversity Wavefront Sensing
Wang Xin, and Zhao Dazun
Phase diversity (PD) is a kind of wavefront sensing technique based on the measurement of two or more object images. The optical system involved is relatively simple. Using the methods of optimization and image processing, it can jointly estimate the phase aberration as well as the object itself simultaneously. HoweverPhase diversity (PD) is a kind of wavefront sensing technique based on the measurement of two or more object images. The optical system involved is relatively simple. Using the methods of optimization and image processing, it can jointly estimate the phase aberration as well as the object itself simultaneously. However, when additive noise appears in the images, many local minimum are produced in the function function. Consequently, the convergence of the algorithm is influenced, or even worse, the algorithm will be trapped in the local minimum which are far from the global minimum. It is necessary to preprocess the image to lower the affection of noise before using the method of optimization. Low pass filter is chosen to eliminate the noise because the images contain less high-frequency components than the lower-frequency ones due to the finite size of the pupil of the optical system. The Butterworth low-pass filter is chosen after considering the performance of some low-pass filters. The research results demonstrate that the speed of convergence and precision of the algorithm is dramatically improved when the filtered images are used, and the RMSE between the estimated and real object is less than before..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2142 (2009)
A New Adaptive Image Denoising Method Based on The Nonsubsampled Contourlet Transform Algorithm
Wu Xiaoyue, Guo Baolong, Tang Lu, and Li Leida
This paper presents a new adaptive image denoising scheme by combining the nonsubsampled contourlet transform (NSCT) and Stein’s unbiased risk estimation (SURE). The original image is first decomposed by using NSCT. Then the mean square error (EMS) is estimated based on Stein’s unbiased risk estimation. The noises of eThis paper presents a new adaptive image denoising scheme by combining the nonsubsampled contourlet transform (NSCT) and Stein’s unbiased risk estimation (SURE). The original image is first decomposed by using NSCT. Then the mean square error (EMS) is estimated based on Stein’s unbiased risk estimation. The noises of each decomposed subband are reduced by using the linear adaptive threshold function, which can be constructed based on the EMS. Finally, the denoised image is obtained after reconstructing the processed subbands. Experiments and comparisons on both standard images and natural images show that the proposed scheme can remove image noises effectively and outperforms the current schemes in regard of both the peak signal-to-noise-ratio (PSNR) and the edge preservation ability..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2147 (2009)
Complete Reconstruction of Non-Convex Surface under Complex IlluminationMa Shuangtao
[in Chinese], [in Chinese], and [in Chinese]
Focusing on the complete reconstruction of non-convex surface under complex illumination, a multi-view reconstruction method is presented. Stereo matching is translated into an issue of color variance minimizing. A threshold is used to balance the contradiction between sampling number and sampling noise, and the ambiguFocusing on the complete reconstruction of non-convex surface under complex illumination, a multi-view reconstruction method is presented. Stereo matching is translated into an issue of color variance minimizing. A threshold is used to balance the contradiction between sampling number and sampling noise, and the ambiguity in stereo match is avoided. By using level set method to deduce the equation of curve surface moving, the object surface is approximated by sign distance function, and the sampling noise is filtered by minimizing the elasticity potential energy, and the robustness for occlusion and illumination condition is strengthened. The experimental results show that the deformable initial surface can shrink to model of object with accuracy and robustness under complex illumination, and the reconstructed time is saved 31~39% than the Jin’s algorithm..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2153 (2009)
A New Iris Edge Extraction Method
Yuan Weiqi, and Bai Xiaoguang
The traditional way of iris location is to extract the iris edge considering it as an ideal circle. To solve the problem that the inner edge of iris is actually not an ideal circle and the outer edge is blurred, a new way to extract the iris edge is proposed in this paper. It firstly unfolds some certain area in iris tThe traditional way of iris location is to extract the iris edge considering it as an ideal circle. To solve the problem that the inner edge of iris is actually not an ideal circle and the outer edge is blurred, a new way to extract the iris edge is proposed in this paper. It firstly unfolds some certain area in iris to a rectangle shape using the pole coordinates transformation, then searches the real inner iris edge according to the steps of grayscale in this rectangular area and finally takes advantages of linear location in this rectangular area to locate the outer iris edge instead of location of that in the human eye images. This method not only solves the problem of pupil carry-over or the texture loss caused by that the inner edge is not an ideal circle but also sharply reduces the location time since it constitutes the point and line detection to the circle detection. Testing on the CASIA-IrisV3 database, the results show that the proposed method costs an average time of 0.172 s and the correct rate is 99.35%..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2158 (2009)
Iterative Restoration Algorithm Based on Expectation Maximization (EM) for Hyperspectral Image
Zhao Huijie, Qu Lei, and Cheng Xuan
The full width at half maximum (FWHM) of spectra of acousto-optic tunable filter (AOTF) and non-ideal transducer structure result directly in image degradation. In order to increase the spatial resolution of hyperspectral images, the expectation-maximization algorithm is ultilized and optimized in pre-processing, and iThe full width at half maximum (FWHM) of spectra of acousto-optic tunable filter (AOTF) and non-ideal transducer structure result directly in image degradation. In order to increase the spatial resolution of hyperspectral images, the expectation-maximization algorithm is ultilized and optimized in pre-processing, and it could also be used even when degration is not accurately estimated. The original target is ultinreately approached by iterative method. Experimental results show that the algorithm does not depend on the assumption of the image spliced periodically, and thus efficiently avoids the defects of the traditional deconvolution method. This method increases the spatial resolution of the image, and improves image quality. It plays a significant role in improving image quality of AOTF hyperspectral image..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2164 (2009)
The Application of Tabu Search on Minimum Discontinuity Phase Unwrapping Algorithm
Zhang Ting, Lu Yuangang, and Zhang Xuping
Flynn′s minimum discontinuity algorithm can be used to successfully solve many different kinds of phase unwrapping problems, but its main drawback is that it requires a large amount of computations and has low efficiency in searching for the phase′s discontinuity areas because it takes the whole phase image as the cyclFlynn′s minimum discontinuity algorithm can be used to successfully solve many different kinds of phase unwrapping problems, but its main drawback is that it requires a large amount of computations and has low efficiency in searching for the phase′s discontinuity areas because it takes the whole phase image as the cycling search area. To overcome this drawback, a new minimum discontinuity algorithm based on tabu search is proposed. In the new algorithm, the quality map of wrapped phase is used to classify the total nodes into several ranks from low to high according to the value of quality. The nodes within high quality areas are temporarily taboo, and those within low-qualified areas are searched for phase discontinuity in priority. This tabu search strategy ensures the search process storts from the areas whose probability of discontinuity are highest, and thus can avoid the useless search as much as possible, speed up the convergence rate of the algorithm, and improve the operational efficiency of the phase unwrapping algorithm significantly..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2169 (2009)
Imaging Systems
Zero Calibration for the Designed Microscanning Thermal Microscopic Imaging System
Gao Meijing, Jin Weiqi, Wang Xia, and Yu Jie
In order to improve the spatial resolution of the optical microscanning thermal microscopic system, the zero of microscanning should be determined to complete the oversample reconstruction. Based on the geometric principle and digital imaging processing, a new zreo calibration was presented. The definition, the workingIn order to improve the spatial resolution of the optical microscanning thermal microscopic system, the zero of microscanning should be determined to complete the oversample reconstruction. Based on the geometric principle and digital imaging processing, a new zreo calibration was presented. The definition, the working principle and the method were analyzed, and the microscanning zero calibration of the real system was done. Different reconstruction methods were applied to reconstruct the thermal image and the real thermal microscopic image, moreover the evaluation parameters were given. Results of simulation and real thermal imaing peocessing show the availability of the zero calibration, thus the high resolution optical microscanning thermal microscopic system has been achieved. The system can be applied into many systems which need microscopic thermal anslysis with high spatial resolution..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2175 (2009)
A Fast Binocular Vision Stereo Matching Algorithm
Di Hongwei, Chai Ying, and Li Kui
To resolve the problem of large computational cost and bad real-time performance of current binocular vision stereo matching algorithm, a fast stereo matching algorithm of parallel system is presented. Firstly, based on the difference oftwo images, the images are divided into feature points and non-feature points. ThenTo resolve the problem of large computational cost and bad real-time performance of current binocular vision stereo matching algorithm, a fast stereo matching algorithm of parallel system is presented. Firstly, based on the difference oftwo images, the images are divided into feature points and non-feature points. Then the feature points are matched using winner-take-all (WTA) method and the non-feature points are validated simply. Finally a dense disparity map is yielded. With the fact that the disparity map consists of piecewise-smooth surfaces, the computational cost is decreased greatly. Experimental results show that the extracted feature points are concentrated in the depth discontinuity regions. Compared with other area-base matching algorithms, the computational speed of the presented algorithm has been improved for one order of magnitude while the percentage of bad matching pixels is equivalent to other algorithms. Besides, the edge feature is better, and thus this method is an effective and feasible stereo matching algorithm with good real-time performance..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2180 (2009)
Relation Between Imaging Quality and Gate-Control Signal of Underwater Range-Gated Imaging System
Sun Jian, Zhang Xiaohui, Ge Weilong, and Zhou Yamin
The transmission character of forward-scattering, backscattering and signal irradiance is studied. An underwater range-gated imaging system is built up with pulse-laser and ICCD. A mathematic method of underwater laser range-gated imaging system is given. The relation between imaging contrast and gate-controlled signalThe transmission character of forward-scattering, backscattering and signal irradiance is studied. An underwater range-gated imaging system is built up with pulse-laser and ICCD. A mathematic method of underwater laser range-gated imaging system is given. The relation between imaging contrast and gate-controlled signal is analyzed. The theoretical calculations are programmed, and figures of image contrast and gate-controlled signal are plotted based on typical system programmed. A best strategy of gate-controlling is raised. Relatively, the experiment has been done. The results show that accurate open-time can acquire the best images, and the image is better when open the gate little-later than ahead with the ICCD not saturated. The duration of gating should one to there times of the pulse width..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2185 (2009)
Instrumentation, Measurement and Metrology
Velocity Measurement of Gas Flow Field by Hydroxyl Tagging Velocimetry
Ye Jingfeng, Hu Zhiyun, Zhang Zhenrong, Liu Jingru, Wang Sheng, Huang Meisheng, Zhang Lirong, and Zhao Xinyan
A single-line hydroxyl tagging velocimetric system for gas flow is constructed. Hydroxyl tagging line is generated through the photodissociation of H2O molecules in flow by a 193 nm pulsed ArF excimer laser beam. A laser sheet from a pulsed frequency-doubled dye laser operating at 282 nm is used to reveal the OH tagginA single-line hydroxyl tagging velocimetric system for gas flow is constructed. Hydroxyl tagging line is generated through the photodissociation of H2O molecules in flow by a 193 nm pulsed ArF excimer laser beam. A laser sheet from a pulsed frequency-doubled dye laser operating at 282 nm is used to reveal the OH tagging line through fluorescence. Two time consecutive images are acquired to calculate the velocity distribution of flow field. The lifetime of OH photoproducts photo-dissociated by 193 nm laser in air and flame are studied. The velocity measurement for room-temperature air flow and high-temperature supersonic flow are carried out, and the basic analysis and discussion of experimental results are performed..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2191 (2009)
Image measure of characters of cavitation bubble by optical breakdown
Zong Siguang, Wang Jiang′an, and Wang Huihua
To study the integration phenomena such as the plasma, high pressure shock wave, cavitation bubbles,bubble crumble lighting when high intensity laser pulses interact with liquid targets, high speed photography technique is used in liquid laser breakdown investigation. Experimental investigation of cavitation bubble aftTo study the integration phenomena such as the plasma, high pressure shock wave, cavitation bubbles,bubble crumble lighting when high intensity laser pulses interact with liquid targets, high speed photography technique is used in liquid laser breakdown investigation. Experimental investigation of cavitation bubble after light breakdown with Nd∶YAG laser pulses in the liquid targets , such as water, glycerin. alcohol, silicon liquid are presented. The experimental investigation of the laser-induced cavitation bubble expansion and collapse were done with high-Speed photography. Based on the analysis of bubble image list,the characteristics of the laser bubbles are gained. It may serve as a tool for the optimization in the bubble study and applications of laser medicine, laser machining and bubble impulsion..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2197 (2009)
Discrimination of Oil Varieties by Using Near Infrared Spectral Technology
Zhou Zili, Jiang Lulu, Tan Lihong, He Yong, Li Xiaoli, and Shao Yongni
A new method for discrimination of oil types by means of near infrared spectroscopy (NIRS) was developed. First, the characteristic spectrums of oil were got through principal component analysis (PCA). The result of the analysis suggests that the reliabilities of first 8 principal components are more than 95.38%. The 2A new method for discrimination of oil types by means of near infrared spectroscopy (NIRS) was developed. First, the characteristic spectrums of oil were got through principal component analysis (PCA). The result of the analysis suggests that the reliabilities of first 8 principal components are more than 95.38%. The 2-dimensional plot was drawn with first and second principal components, which indicates that it is a good clustering analysis for classification of oil varieties. Several variables compressed by PCA were used as inputs of multiple discriminant analysis (MDA).150 samples from three varieties were selected randomly, then they were used to build discrimination model. 30 unknown samples were predicted by this model, and the recognition rate is 100%. This model is reliable and practicable. It could offer a new approach to the fast discrimination of oil types..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2203 (2009)
Experimental Study on Angle-resolved Light Intensity Scattered Profile and Roughness Exponent of Self-affine Fractal Surface
Zhang Ningyu, Cheng Chuanfu, Zhang Junchao, and Teng Shuyun
The new experimental measurement system is set up to measure light intensities scattered from the reflection-mode random surface. By using the technique of data average and overlay connection, the functions of scattered light intensity profiles are calculated at different incidence angles (45°～85°) on random The new experimental measurement system is set up to measure light intensities scattered from the reflection-mode random surface. By using the technique of data average and overlay connection, the functions of scattered light intensity profiles are calculated at different incidence angles (45°～85°) on random surface. The results show that the full widths at half-maximum of intensity profiles are decreased gradually with increased of the incidence angles. While the incidence angle increases to a certain value, the light intensity scattered profile presents a central bright spot. Based on the symmetric decline function in mathematics, the relationship between the full width at half-maximum of intensity profile and the light wave vector is deduced, and the roughness exponent of self-affine fractal surface is extracted from angle-resolved scattered light intensity profiles. It is obvious that the obtained value of roughness exponent is in good agrement with that measured by atomic force microscop..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2208 (2009)
Spectroscopic Diagnostication of Transient Excitation and Radiation Temperature of Plasma
Shen Hua, Chen Lei, Zhu Rihong, and Ma Suodong
Variation of the transient temperature of transient physical field can be diagnosticated indirectly by measuring the temperature of the plasma. Spectrum of the plasma is gathered by the telescope which is the prepositive optical device of the system. Four characteristic spectral signals from the atom excitation are sepVariation of the transient temperature of transient physical field can be diagnosticated indirectly by measuring the temperature of the plasma. Spectrum of the plasma is gathered by the telescope which is the prepositive optical device of the system. Four characteristic spectral signals from the atom excitation are separated accurately (Δλ<0.1 nm) from the light of the plasma by the diffraction grating. Photomultiplier tubes (PMTs) with high sensitivity and short response time (＜1 μs) detect the four signals through the optical fiber, for satisfying the request of the transient measurement. Calculation precision （better than 2%） of the excitation temperature is increased by fitting Boltzmann line with four data. Computational model of the radiation temperature is deduced based on Planck’s blackbody radiation theorem. Transient excitation and radiation temperatures of the plasma are calculated isochronously by measuring light intensity once. Modulus of the spectral response of the system is calibrated by standard lamp. The results of the experiment show that the precision of the system is better than 3%..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2216 (2009)
Effect of Magneto-Optic Rotation Enhancement and the Polarimetric Detection of the Small Rotation Angles
Liang Zhongcheng, and Zhao Rui
One of the developing trend of microfluidic technology is the integration and miniaturization of the optical detection system. In the meantime, the polarimetric detection of microfluidic system is also one of the important research topics. In this work, the polarized characteristics of polarimetric reflection cavity emOne of the developing trend of microfluidic technology is the integration and miniaturization of the optical detection system. In the meantime, the polarimetric detection of microfluidic system is also one of the important research topics. In this work, the polarized characteristics of polarimetric reflection cavity embedded with Faraday magneto-optic medium is analyzed in detail. It is predicted that such a rotatory reflection cavity has the effect of megneto-optic rotation enhancement. Base on this phenomenon, the method for the angle detection of small amount sample and the theory for the feature analysis of Faraday rotation devices are proposed. The results show that the method can significantly improve the detection sensitivity of magneto-optic rotation media under conditions where the optical path is sieriously restricted. The theoretical limitation of the relative sensitivity with polarimetric detection is 78.5. The method can be applied to the megneto-optical rotation detection of microfluidic system and miniaturize the megneto-optic polarimetric instruments..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2221 (2009)
Lasers and Laser Optics
Theoretical Research of Pulse Pumped Yb-Doped Pulse Fiber Amplifier
Zhao Xiaojun, Wu Bo, Yang Zehou, Zhou Dingfu, Chen Jianguo, Xiao Yongliang, Wang Conggang, and Du Weimin
A theoretical analysis is made on pulse pumped double-clad Yb-doped fiber amplifier based on master oscillator power-amplifier(MOPA). The interaction processes of the pumping pulse, laser pulse and Raman Stokes optical pulse during the fiber amplification have been analyzed. The change of the upper level population denA theoretical analysis is made on pulse pumped double-clad Yb-doped fiber amplifier based on master oscillator power-amplifier(MOPA). The interaction processes of the pumping pulse, laser pulse and Raman Stokes optical pulse during the fiber amplification have been analyzed. The change of the upper level population density of the gain fiber with the pumping duration is simulated, and the optimal pumping pulse width is found. With the pumping power increasing, the stimulated Raman effect appeared during the amplification process will restrain the signal pulse energy. The signal pulse energy can reach the peak under the optimal pumping power. The effect of the fiber length and core diameter on the optimum pumping power, laser pulse and first-order Stokes optical pulse is analyzed too. Results show that when the pumping power is the optimum, the bigger core and shorter length fiber should be used in the fiber amplifier in order to increase the signal pulse energy and peak power as much as possible..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2225 (2009)
Theoretical and Experimental Investigation on Coherent Beam Combining of Fiber Lasers Using SPGD Algorithm
Zhou Pu, Liu Zejin, Wang Xiaolin, Ma Yanxing, and Xu Xiaojun
The fundamental theory for coherent beam combining using SPGD algorithm is introduced. The evaluation function, perturbation mode and the distribution character of perturbation voltages are optimized by using numerical simulation. Coherent beam combining of three W-level polarize-maintained fiber amplifiers is accompliThe fundamental theory for coherent beam combining using SPGD algorithm is introduced. The evaluation function, perturbation mode and the distribution character of perturbation voltages are optimized by using numerical simulation. Coherent beam combining of three W-level polarize-maintained fiber amplifiers is accomplished by implementing SPGD algorithm on a digital signal processor. The experimental results demonstrate that the optical phase for each beam channel can be effectively controlled by the SPGD algorithm, the energy encircled in the target pinhole is increased by a factor of 2.62, and the combining efficiency is as high as 87% compared with its ideal counterpart when the system is in the close-loop..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2232 (2009)
Three-Dimensional Simulation Analysis of Ray Trace for Lens Duct as A Coupling System
Fan Shuwei, and Shen Yuting
Laser diode (LD) pump coupling system is an important part of the solid-state lasers. Non-imaging system consisting of hollow lens duct coupling system is ideal for high-power semiconductor laser array. Based on geometric optics theory, the mathematic model of three-dimensional (3D) light transmission in hollow lens duLaser diode (LD) pump coupling system is an important part of the solid-state lasers. Non-imaging system consisting of hollow lens duct coupling system is ideal for high-power semiconductor laser array. Based on geometric optics theory, the mathematic model of three-dimensional (3D) light transmission in hollow lens duct was developed, and 3D ray trace equations were clearly presented. With the help of theoretical analysis of three-dimensional ray trace, a 3D simulation software of ray transmission for lens duct as coupling systems was developed. The real transmission trace of all the pump rays can be shown automatically with the developed 3D software and the pump light distribution in output of lens duct also can be given. Finally. The coupling energy efficiency coming through the hollow lens duct was discussed. The results show that the coupling energy efficiency of the hollow lens duct can reach more than 96.08%..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2238 (2009)
Bound State Operations in Stretched-Pulse Mode-Locking Large-Mode-Area Photonic-Crystal-Fiber Laser
Zhang Xin, Hu Minglie, Song Youjian, Chai Lu, and Wang Qingyue
Bound states in a stretched-pulse large-mode-area photonic crystal fiber mode-locking laser operating in the vicinity of zero dispersion regime is demonstrated, where the double pulse and multi-pulse bound state mode-locking are obtained. The experiment shows that the separation between sub-pulses is unequal with some Bound states in a stretched-pulse large-mode-area photonic crystal fiber mode-locking laser operating in the vicinity of zero dispersion regime is demonstrated, where the double pulse and multi-pulse bound state mode-locking are obtained. The experiment shows that the separation between sub-pulses is unequal with some randomicity. A numerical model of the mode-locked fiber laser is established and the simulations show that the laser can operate either with single-pulse or with multi-pulse in a certain pump power range depending on semiconductor saturable absorber mirror (SESAM), which selects signal randomly from noise. And the characteristic of the multi-pulse bound states and randomicity of the distance between sub-pulses are researched. The results can be used to enhance the single pulse energy, which indicated that the highest pulse energy of 19.6 nJ can be obtained with a compressed pulse duration of 76 fs and a reduced pulse energy of 11.8 nJ due to about 40% compression loss. The numerical simulation agrees well with the experiment..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2243 (2009)
Study on Far-Field Intensity Distribution of Fiber Laser Used in Coherent Beam Combination
Wang Wei, He Bing, Zhou Jun, Lou Qihong, Liu Xia, Zhang Fangpei, Zhao Hongming, and Xu Hui
In coherent beam combination with fiber lasers, the phases, amplitudes and polarization directions of each laser are different, influenced by manufacturing process, environment and others. The far-field intensity distribution and beam quality of lasers with coherent beam combination are studied and calculated. NumericaIn coherent beam combination with fiber lasers, the phases, amplitudes and polarization directions of each laser are different, influenced by manufacturing process, environment and others. The far-field intensity distribution and beam quality of lasers with coherent beam combination are studied and calculated. Numerical results show that the figure of far-field light distribution, the light intensity of peak value, and the power of the central region degenerate or trail off in varying degrees..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2248 (2009)
Preliminary Study of Dithering Frequency Stabilization for Four-Frequency Differential Laser Gyro
Yang Jianqiang, and Liao Dan
To overcome the disadvantages of light intensity difference frequency stabilization, the dithering frequency stabilization for four frequency differential laser gyro is studied in this paper. Based on the principle of laser gyro, the characteristics and difficulties of the dithering frequency stabilization are analyzedTo overcome the disadvantages of light intensity difference frequency stabilization, the dithering frequency stabilization for four frequency differential laser gyro is studied in this paper. Based on the principle of laser gyro, the characteristics and difficulties of the dithering frequency stabilization are analyzed, including the low frequency sensitivity, the severe deviation of operating point at inappropriate gyro parameters, the indistinguishable operating mode and the zero shift problem resulting from the frequency precision. The solutions of each difficulty are presented, the design of low noise circuits is the key factor to improve the precision of the dithering frequency stabilization, which will be helpful to the further experimental study..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2256 (2009)
Materials
Tolerance of Thickness Fluctuations of Quasi-Fractal Photonic Crystal Filter
Xu Pan, Tian Huiping, Li Changhong, and Ji Yuefeng
In order to research the influence of layer thickness fluctuations on the performance of quasi-fractal photonic crystal filter and to find out the tolerance of the thickness fluctuations, the influence of layer thickness fluctuation on the filter properties of quasi-fractal photonic crystal filter containing negative mIn order to research the influence of layer thickness fluctuations on the performance of quasi-fractal photonic crystal filter and to find out the tolerance of the thickness fluctuations, the influence of layer thickness fluctuation on the filter properties of quasi-fractal photonic crystal filter containing negative material is analyzed through adding different thickness fluctuations both in positive and negative refractive index layers. Laws of the transmission peak shifting with the refractive index, number of the layers and the thickness of layer fluctuation are summarized. The statistic figures of the positions of the transmission peaks are simulated and the statistic feature of the position of the transmission peaks are analyzed when the random geometric thickness fluctuations are added in each layer. The conclusion is that the tolerance of random geometric thickness fluctuation of this kind of photonic crystal filter used in dense wavelength dovision multioplexing (DWDM) optical communication system is only 0.01 nm..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2308 (2009)
Simulation of the Photonic Band Gap of One-Dimensional Photonic Crystal and Experimental Study in Microwave Region
Wang Ji, Lin Qingyong, Gu Chunhui, and Gong Junfeng
The photonic band gap (PBG) and transmission of one-dimensional photonic crystal are studied with two simulation software: MPB and MEEP in microwave region. The influence of the different ratio and the relative dielectric constant of the medium on PBG is studied. The simulation result shows that as the ratio of the higThe photonic band gap (PBG) and transmission of one-dimensional photonic crystal are studied with two simulation software: MPB and MEEP in microwave region. The influence of the different ratio and the relative dielectric constant of the medium on PBG is studied. The simulation result shows that as the ratio of the high relative dielectric medium increases or the high relative dielectric constant itself increases, the center frequency of the PBG will decrease slowly and the width of the PBG will firstly increase and then decrease, which forms a maxima. A kind of material of photonic crystal is fabricated with dielectric sheets which consists of a BaTiO3 powder and PDMS and foam sheets arraying in cyclical order. A one-dimensional photonic crystal is made, of which the high relative dielectric constant is 4.5, the low relative dielectric constant is 1, the ratio of materials is 1∶1, the lattice constant is 10 mm and the cycle is 5. The transmission of that one-dimensional photonic crystal is measured experimentally. Result shows that is the region from 8~12 GHz, the center frequency of the PBG is 9.3 GHz and the width of the PBG is 500 MHz..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2313 (2009)
Focus Achieved by a Slab Lens of Quasiperiodic Photonic Crystal
Ren Kun, and Ren Xiaobin
A type of quasiperiod photonic crystal (QPC) that can achieve negative refraction is proposed. The QPC has 12-fold symmetry and consists of a quasiperiod array of air-holes arranged in a dielectric background. The propagation of electromagnetic wave across the 12-fold quasicrystal is investigated by employing finite diA type of quasiperiod photonic crystal (QPC) that can achieve negative refraction is proposed. The QPC has 12-fold symmetry and consists of a quasiperiod array of air-holes arranged in a dielectric background. The propagation of electromagnetic wave across the 12-fold quasicrystal is investigated by employing finite difference time domain method. Simulation on the wedge-shaped sample demonstrates that negative refraction can occur in the quasicrystal structure. Parallel QPC slab is further designed to explore the influence of surface termination of flat slab on the propagation of electromagnetic wave. The results show that by changing the surface termination of flat slab, the electromagnetic field distribution behind the slab can be modulated. Under appropriate surface condition, focusing can be obtained by the QPC slab. As a result, proper surface parameter should be carefully chosen for practical applications..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2317 (2009)
Medical Optics and Biotechnology
Study of Autofluorescence Spectrum between Hepatic Carcinoma Cell and Hepatic Cell
Li Jing, Zeng Hongjuan, and Pang Xiaofeng
The objective of the autofuorescence spectrum of hepatic carcinoma cell and hepatic cell studied was to understand if there was difference between the two cells. So we cultured SMMC-7721 hepatic carcinoma cell and HL-7702 hepatic cell in vitro. Then their autofuorescence was detected by fluorescent spectrograph. It preThe objective of the autofuorescence spectrum of hepatic carcinoma cell and hepatic cell studied was to understand if there was difference between the two cells. So we cultured SMMC-7721 hepatic carcinoma cell and HL-7702 hepatic cell in vitro. Then their autofuorescence was detected by fluorescent spectrograph. It presents that the spectrogram of the hepatic carcinoma cell resembles that of the hepatic cell at the range of wavelength from 550～720 nm characterized by two peaks at 602 nm and 691 nm. But from 721～800 nm, the spectra of carcinoma cell with a peak located at 734 nm were found. For the hepatic cell the peak at 734 nm was not observed. The experimentations of propagation of both cells confirm ulteriorly that there is a significant difference between two cells'spectrum. The experiment will be beneficial to the next research of detecting hepatic carcinoma by fluorescent fiber optic biosensor..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2261 (2009)
Nonlinear Optics
Incoherently Coupled Soliton Family Supported by Two-Photon Isomerization Nonlinearity
Wang Hongcheng, Peng Xiaolan, Chen Shaowen, Li Hongtao, and Ling Dongxiong
A theory is presented to investigate the existence of incoherent coupled soliton family supported by two-photon isomerization nonlinearity. It is found that incoherent coupled gray and dark soliton families can exist in bulk polymers with the two-photon isomerization(TPI) nonlinearity. These soliton families can be estA theory is presented to investigate the existence of incoherent coupled soliton family supported by two-photon isomerization nonlinearity. It is found that incoherent coupled gray and dark soliton families can exist in bulk polymers with the two-photon isomerization(TPI) nonlinearity. These soliton families can be established provided that their components have the same polarization and wavelength, and are mutually incoherent. The existing conditions and properties of this kind of incoherent coupled gray and dark soliton families are investigated in detail by numerical method. Each component of an incoherent coupled soliton family has the same full width of half maximum. When this incoherent coupled gray or dark soliton family propagates together, all the components can propagate stably in the polymers with two-photon isomerization nonlinearity. The investigation shows that the components of a gray soliton family have a transverse velocity, while those of dark soliton family don’t move in the transverse direction. If there are only two components, incoherent coupled TPI soliton families automatically degenerates to incoherent coupled TPI gray or dark soliton pairs..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2264 (2009)
Analysis of the Switching Characters of Soliton in Two Optical Lattices with Modulation of Multiple Periods
Zhou Jun, Meng Xiaobo, Ren Chunyang, Gao Yongfeng, and Chen Mingyang
Two multiple-period modulation optical lattices with Kerr-type nonlinear medium were proposed. The switching characters of soliton in these lattices were studied and compared with that of the single-period cosine-type modulation optical lattices. The stabilities of the energy of soliton pulse in all of these optical laTwo multiple-period modulation optical lattices with Kerr-type nonlinear medium were proposed. The switching characters of soliton in these lattices were studied and compared with that of the single-period cosine-type modulation optical lattices. The stabilities of the energy of soliton pulse in all of these optical lattices was numerically analyzed, and the numbers of the channels which were traversed by soliton pulse were numerically calculated before the soliton pulse was trapped in the lattices channel. Within the same energy region, the numbers of switching channels of the soliton were obviously different. And for the same numbers of channels traversed, the response time were different..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2270 (2009)
Optical Design and Fabrication
Design of Grazing Incidence Optical System
Li Shun, and Gong Yan
The basic structure of classical Wolter type I grazing incidence optical system was presented. And a set of equations, through which the main basic parameters of a grazing incidence optical system were calculated, were calculated from the common equations of those reflecting surfaces. In addition, it was discussed thatThe basic structure of classical Wolter type I grazing incidence optical system was presented. And a set of equations, through which the main basic parameters of a grazing incidence optical system were calculated, were calculated from the common equations of those reflecting surfaces. In addition, it was discussed that how to evaluate and optimize the classical Wolter type I grazing incidence optical system using optical design code Zemax’s macro language. And specific optimized example was discussed. A hyperboloid-hyperboloid grazing incidence optical system with the same aperture and focal length is achieved from the classical paraboloid-hyperboloid Wolter type I. And the evaluation results of those two grazing incidence optical system show that the optical system’s resolution for wide-field has significant improvement and it could meet top-resolution full-disk solar observation requirement.<收到修改稿日期李顺>2008-12-02.
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2276 (2009)
Design and Experiment of Projection Display Optical System Based on Grating Light Modulator
Zhang Jie, Sun Jiyong, Qing Yi, Zhang Zhihai, and Zhu Yong
A micromachined optical modulator called grating light modulator (GLM) with electrostatic actuation, fabricated by the conventional process, is described. GLM modulates the light energy by changing the distance of the movable grating and the underlying fixed reflector, which can be applied in projection display in fourA micromachined optical modulator called grating light modulator (GLM) with electrostatic actuation, fabricated by the conventional process, is described. GLM modulates the light energy by changing the distance of the movable grating and the underlying fixed reflector, which can be applied in projection display in four-focus optical system. With the typical four-focus optical system, the projection display optical system based on GLM is optimized and designed, which is analyzed by Fresnel diffraction. The static and dynamic display experimental systems are designed. The experimental results indicate that the GLM technique has characteristics that make it suitable for projection display applications and several characteristic measurement experiments can be carried on by using such system, such as the working voltage, the pull-in voltage, the response frequency and so on..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2282 (2009)
Performance Analysis on Solar Cell Modules of Flat-Plate and Trough Concentrating Photovoltaic System
Wang Yunfeng, Li Ming, Lin Wenxian, Wang Liuling, Wei Shengxian, Xu Yongfeng, Zhang Xinghua, and Xiang Ming
The comparative experiments of solar cell module of single crystalline silicon and trough concentrating photo-voltaic/thermal (PV/T) system of super cells were made from the thermal and electrical persectives, and the economics of these two systems were aslo analyzed with the method of “net present value”. The results The comparative experiments of solar cell module of single crystalline silicon and trough concentrating photo-voltaic/thermal (PV/T) system of super cells were made from the thermal and electrical persectives, and the economics of these two systems were aslo analyzed with the method of “net present value”. The results indicate that the maximum output electric power of trough concentrating PV/T system is 7-10 times that of flat-plate photo-voltaic (PV) system. The PV/T system can generate heat about 2929.433 MJ per year by recycling the surplus heat of solar cell. Within the life time of 20 years, The PV/T system can acquire more surpluses and take investment cost back soon. Using concentrator for solar cell, the utilization of solar energy can be enhanced effectively with reduction in the investment cost..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2287 (2009)
Design of High-Efficiency Beam Dividing System Used in Active-Passive Composite Imaging Radar
Liu Liping, Sun Xiudong, Zhao Yuan, Jin Chenfei, and Zhang Yong
A high-efficiency beam dividing system design was accomplished, which could be used in the receiving optical system of the active-passive composite image radar to divide the active beam from the passive beam. The beam dividing system could divide the active beam with wavelength of 850 nm, view field angle of 3.5°fA high-efficiency beam dividing system design was accomplished, which could be used in the receiving optical system of the active-passive composite image radar to divide the active beam from the passive beam. The beam dividing system could divide the active beam with wavelength of 850 nm, view field angle of 3.5°from the passive beam with wavelength of 9.7 μm and view field angle of 6.9°. The efficiency of the beam dividing system is over 98% for both active beam and passive beam. In addition, the structure stabilization and technical facility are the other advantages of the design. The beam dividing system design could share the same aperture for both active beam and passive beam which is important to achieve the miniaturization of active-passive composite image radar..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2293 (2009)
Design for LED Uniform Illumination Reflector Based on tendue
Yu Guiying, Jin Ji, Ni Xiaowu, and Zheng Yingjun
In view of light-emitting diode (LED) light source’s characteristics, according to the étendue conservation theory in non-imaging optics, the improved reflection equations for obtaining uniform illumination are derived and the uniform illumination in specific target plane is achieved. Based on the equations, an ilIn view of light-emitting diode (LED) light source’s characteristics, according to the étendue conservation theory in non-imaging optics, the improved reflection equations for obtaining uniform illumination are derived and the uniform illumination in specific target plane is achieved. Based on the equations, an illumination system of LED-base stereomicroscope is designed. Using software Tracepro, the ray-tracing simulations show that, in the scope of Φ90 mm, the uniformity of illumination reaches 90.6%, and the efficiency can reach 99.6% without considering the loss. This scheme uses only one single reflector to achieve uniform illumination and provides an effective way for realizing system’s miniaturization and simplification..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2297 (2009)
Optical Devices
nvestigation of Back-Reflection of Ring Resonator in Resonator Optic Gyro
IZhang Xulin, and Xu Ping
Back-reflection is one of the important noise sources in the resonator optic gyro (ROG). Using optical field overlapping method, the single-reflection-model inside the ring resonator was set up and the relation between the scale-factor error and the parameters about reflection noise was gotten. By the numerical analysiBack-reflection is one of the important noise sources in the resonator optic gyro (ROG). Using optical field overlapping method, the single-reflection-model inside the ring resonator was set up and the relation between the scale-factor error and the parameters about reflection noise was gotten. By the numerical analysis in Matlab, the back-reflection noise in the resonator fiber-optic gyro (R-FOG) and the resonator micro-optic gyro (R-MOG) was analyzed and compared in theory. The open-loop output signal in ROG was detected by taking some countermeasure to overcome the noise caused by the backscattering. It was proved theoretically and experimentally that the noise caused by the back-reflection influences the R-MOG more severely..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2302 (2009)
Physical Optics
Superposition Mechanism of Pulse Train′s Transmission in Semitransparent Medium
Liu Lijun, and Liu Linhua
Based on the scattering and refraction characteristics of optical waves in medium, the superposition mechanism of pulse trains after interface reflection and medium scattering is researched. Analytical solutions of the transmittance and reflectance of pulse trains in non-scattering semitransparent slab are deduced. TheBased on the scattering and refraction characteristics of optical waves in medium, the superposition mechanism of pulse trains after interface reflection and medium scattering is researched. Analytical solutions of the transmittance and reflectance of pulse trains in non-scattering semitransparent slab are deduced. The discontinuous finite element method and time shift and superposition method are used to calculate the transmittance and reflectance in one-dimensional scattering slab medium. The results show that the pulse train, reflected by interface and scattered by medium is split into a series of sub-lightwaves with different time delays due to the interaction of incident light and medium. After passing different optical path, the sub-lightwaves are superposed as the reflected and transmitted light waves leaving the slab. The superposition effects vary with the variation of scattering coefficient, pulse width and time interval. Regulating pulse width and time interval of pulse trains will produce the reflected and transmitted light waves with different wave shapes..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2320 (2009)
Remote Sensing and Sensors
Synthetic Aperture Imaging Ladar (VI)∶ Space-Time Speckle Effect and Heterodyne Signal-to-Noise Ratio
Liu Liren
The effect of laser speckle on heterodyne detection for synthetic aperture imaging ladar (SAIL) is investigated. The smooth effect due to the finite aperture of SAIL antenna is considered, and particularly the statistical characteristics of the time-varying speckle pattern is explored and mathematically analyzed, whichThe effect of laser speckle on heterodyne detection for synthetic aperture imaging ladar (SAIL) is investigated. The smooth effect due to the finite aperture of SAIL antenna is considered, and particularly the statistical characteristics of the time-varying speckle pattern is explored and mathematically analyzed, which is caused from the frequency modulation of laser within a single look. As a result, the signal-to-noise ratio of photon-limited heterodyne detection due to the space-time speckle effect is given..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2326 (2009)
Thin Films
Multi-Channel Absorption Measurement of Optical Coatings Based on Image Lock-in Technique
Tao Chunxian, Zhao Yuan′an, He Hongbo, and Shao Jianda
The absorption detection of optical coatings is studied in theory and application. A novel method of multichannel measurement based on image lock-in is presented. The comparison between the calculated measuring results of point by point method and multichannel method is made, which proves the feasibility of the multichThe absorption detection of optical coatings is studied in theory and application. A novel method of multichannel measurement based on image lock-in is presented. The comparison between the calculated measuring results of point by point method and multichannel method is made, which proves the feasibility of the multichannel method for large scaled coatings measurement. Through calculation, it is known that the measuring speed of image method can be increased more than hundreds of times compared with that of the past. This technique avoids the weakness of long time-consuming and low efficiency in traditional method and expands the application of photothermal technique in large scale optical coatings..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2333 (2009)
Goos-Hanchen Shift and Pulse Deformation Properties in Thin Film-Grating Hybrid Structures
Luo Zhenyue, Liu Xu, Xue Hui, Shen Weidong, and Gu Peifu
Large Goos-Hanchen(GH) lateral shift and beam deformation for the guided mode resonant filter are fully discussed. Simulation results proved that this structure could generate lateral displacement as large as 300 λ0. Light waves that experience largest lateral displacement have maximum reflectivity, so it is relativelyLarge Goos-Hanchen(GH) lateral shift and beam deformation for the guided mode resonant filter are fully discussed. Simulation results proved that this structure could generate lateral displacement as large as 300 λ0. Light waves that experience largest lateral displacement have maximum reflectivity, so it is relatively easier for experimental verification, and would facilitate practical application for its high energy utilization. Two analysis methods based on stationary approach and Gaussian angular decomposition technique are applied, and the lateral shift properties as well as companied beam deformation is fully analyzed. Dependence of the lateral displacement depends on the incident beam width is mainly discussed. This theoretical analysis paves the wave for the next step of manufacturing and testing..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2338 (2009)
Ultrafast Optics
Carrier Dynamics of Intrinsic CdTe by Pump-Probe Reflection Spectroscopy
Jin Zuanming, Ma Hong, Li Dong, and Ma Guohong
The transient carrier dynamics of intrinsic CdTe was investigated by time-resolved femtosecond pump-probe reflection spectroscopy method (PPR) at different wavelengths and powers. The experimental results show that the percentage of the rapid process in carrier relaxation process grows with the increase of the pumped pThe transient carrier dynamics of intrinsic CdTe was investigated by time-resolved femtosecond pump-probe reflection spectroscopy method (PPR) at different wavelengths and powers. The experimental results show that the percentage of the rapid process in carrier relaxation process grows with the increase of the pumped photon energy. The rapid process constant and reflectivity increase when the pumped optical power increases. The model of ultrafast carrier dynamics in intrinsic semiconductor was developed, and the effects of carrier initial scattering, carrier-LO phonon interaction and carrier trapping on carrier relaxation properties were analyzed. The curve of the PPR at the photon energy of 1.49 eV (～20 mV more than the band gap of CdTe ) is measured, the fast time constant and the slow one are 2.8 ps and 158.3 ps respectively..
Acta Optica Sinica
- Publication Date: Jun. 19, 2020
- Vol. 29, Issue 8, 2343 (2009)
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