Contents
2015
Volume: 35 Issue 4
51 Article(s)
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Atmospheric Optics and Oceanic Optics
Motion Status Identification of Space Object by Analyzing Time Series Multi-Spectral Signal
Hou Qingyu, Wang Fugang, Zhi Xiyang, and Zeng Chengyu
To characterize the motion statuses of spin- stabilized, three- axis stabilized and“tumbling”for non- resolved satellites, a method of the motion status indentification based on time series visible multispectral signal is proposed. The corresponding relationship is analyzed between motion statuses and timevariant typesTo characterize the motion statuses of spin- stabilized, three- axis stabilized and“tumbling”for non- resolved satellites, a method of the motion status indentification based on time series visible multispectral signal is proposed. The corresponding relationship is analyzed between motion statuses and timevariant types of satellite surface material as well as the correlation between material characteristics and the clustering information on the time series dual- color ratio. A discrimination algorithm on types of surface material and an identification algorithm on motion status are proposed on the basis of the time series dualcolor ratio feature in Gaussian mixture clustering. Considering characteristics of background, materials, structure and orbit of the satellite, mathematical simulations for time series multi- spectral signals generated from satellites with the above three motion statuses are operated. The identification algorithm is validated based on the simulated data, and results show that the proposed algorithm is effective..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 401001 (2015)
Statistical Analysis of Atmospheric Refractive Index Structure Parameter Under the Sea Surface Environment
Wu Xiaojun, Wang Hongxing, Li Bifeng, and Liu Chuanhui
Atmospheric refractive index structure parameter ( C2n ) is one of the impotant physical quantities measuring the degree of turbulence. The refractive index structure parameter under the sea surface environment in Yantai region from January to June in 2014 is measured by using a large aperture scintillometer. The statiAtmospheric refractive index structure parameter ( C2n ) is one of the impotant physical quantities measuring the degree of turbulence. The refractive index structure parameter under the sea surface environment in Yantai region from January to June in 2014 is measured by using a large aperture scintillometer. The statistical properties of measured data are analyzed, including frequency count, daily variation and monthly variation. The change characteristics of C2n under the sea surface are compared with other environments. The comparative analysis result reveals that the value of C2n varies between 10-17 m-2/3 to 10-14 m-2/3 under the sea surface environment, which is classified as medium and weak turbulence. The C2n at different times are not presented the variable characteristics of“conversion time”, and there are no significant differences between C2n in the daytime and C2n at night. The daily mean vary between 10- 16 m-2/3 to 10- 14 m-2/3 . At the same time, the discrete degree of C2n is analyzed combing standard deviation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 401002 (2015)
Reconstruction of Spatial Distributions of Industrial Emissions Based on Scaning Multi-Axis DOAS Tomography
Li Suwen, Wei Minhong, Dai Haifeng, and Wang Jiangtao
The spatial distributions of industrial emissions are difficult to get to reconstruct emissions of industrial chimneys in real time. A method is developed to reconstruct spatial distributions of emissions of industrial chimneys based on timing scanning multi-axis differential optical absorption spectroscopy (MAX-DOAS),The spatial distributions of industrial emissions are difficult to get to reconstruct emissions of industrial chimneys in real time. A method is developed to reconstruct spatial distributions of emissions of industrial chimneys based on timing scanning multi-axis differential optical absorption spectroscopy (MAX-DOAS), combined with computed tomography. Visual spatial distribution of concentrations of industrial gas plume vertical section is formed in this paper. The scanning MAX-DOAS are placed on each side of industrial chimneys. The beam ray geometry configuration and line integral concentrations for projection are used to reconstruct spatial distribution of industrial emissions, based on algorithm of smooth basis function minimization(SBFM). The simulated distributions of the plume are given. The applied fields of reconstruction device are also discussed. Finally, this system is used to reconstruct emissions of NO2 of power plant the in field campaign..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 401003 (2015)
Analysis of Uncertainties Associated to Underwater Hyperspectral Attenuation Measurements
Zhao Liancheng, Mao Zhihua, Tao Bangyi, Chen Peng, and Zhu Qiankun
The uncertainty for the underwater hyperspectral measurement of attenuation (ACS) is studied. The attenuation measurements for standard particles of different diameters (2,5,10,20 mm) by ultra violetvisible (UV-Vis) spectrophotometer (PE35) are compared with model values by Mie scattering theory, and the attenuation meThe uncertainty for the underwater hyperspectral measurement of attenuation (ACS) is studied. The attenuation measurements for standard particles of different diameters (2,5,10,20 mm) by ultra violetvisible (UV-Vis) spectrophotometer (PE35) are compared with model values by Mie scattering theory, and the attenuation measurement error of PE35 is found less than 8% . Subsequently, simultaneous atlenuation measurements by ACS and PE35 are carried out for samples from the high turbid water in the East China Sea. Comparative results show the attenuation measurements by ACS are underestimated in high turbid water, and the uncertainty of ACS measurements has a negative correlation with wavelength, conversely, with a strong positive correlation with turbidity of water. The attenuation measurements of ACS(10 cm) and ACS(25 cm) are underestimated within 17.2% ~19.04% and 7.84% ~15.36% in low turbid water, respectively, while ACS(10 cm) is within 26.4%~28.24% in high turbid water..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 401004 (2015)
Modeling and Simulation of Bi-Dimensional Correlated K-Distributed Turbulent Channel
Ke Xizheng, and Tian Xiaochao
The model of bi-dimensional correlated K-distributed Random turbulent is attained by the modified spherically invariant random process (SIRP) method. Then the bi-dimensional correlated K-distributed Random fields are obtained on the base of the assumption of spatial correlation on the one- norm. The various state experThe model of bi-dimensional correlated K-distributed Random turbulent is attained by the modified spherically invariant random process (SIRP) method. Then the bi-dimensional correlated K-distributed Random fields are obtained on the base of the assumption of spatial correlation on the one- norm. The various state experience problems of SIRP method are resolved, which is the inherent characteristic of SIRP method. The slot error rate and channel capacity of bi-dimensional correlated K-distributed channel model are caculated, compared with K-distributed channel model. The results indicate that the method of simulation of turbulent channel can be well controlled by the K-distribution of turbulent component distribution and statistical characteristics, and the validity of this modeling lays the foundation for the research of channel estimation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 401005 (2015)
Fiber Optics and Optical Communications
Supercontinuum Generation Based on Dual-Wavelength Coherent Ultrashort Pulses
Li Min, Huo Li, Wang Dong, Wang Qiang, Jiang Xiangyu, and Lou Caiyun
Supercontinuum around 1550 nm using a dual- wavelength coherent ultrashort pulse source is demonstrated.Dual-wavelength pulse pumping can strengthen the processes of four-wave-mixing and crossphase-modulation, thus, it generates a much broader supercontinuum than regular single- wavelength pumping at the same pump poweSupercontinuum around 1550 nm using a dual- wavelength coherent ultrashort pulse source is demonstrated.Dual-wavelength pulse pumping can strengthen the processes of four-wave-mixing and crossphase-modulation, thus, it generates a much broader supercontinuum than regular single- wavelength pumping at the same pump power. Based on pulse carver and Mamyshev regenerator 25 GHz dual-wavelength coherent ultrashort pulse source,130 nm supercontinuum is experimentally obtained with a pump power of 24.1 dBm.Coherence between the spectral lines is also verified..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 406001 (2015)
Partial Discharge Acoustic Emission Sensor Design Based on Extrinsic Fiber Fabry-Perot Interferometer
Zhang Weichao, Zhao Hong, and Chu Xiong
An extrinsic Fabry-Perot interferometer (EFPI) consisted of coupling quartz diaphragm and fiber optic pigtails is designed to detect acoustic signal generated by partial discharge (PD) in liquid-solid dielectric insulation.To solve the problem of low sensitivity,based on the theory of elasticity the structure parameterAn extrinsic Fabry-Perot interferometer (EFPI) consisted of coupling quartz diaphragm and fiber optic pigtails is designed to detect acoustic signal generated by partial discharge (PD) in liquid-solid dielectric insulation.To solve the problem of low sensitivity,based on the theory of elasticity the structure parameters of EFPI diaphragm are determined using finite element analysis method,and EFPI samples are manufactured.In order to demodulate acoustic signal,a quadrature intensity demodulation system is established using distribute feedback (DFB) laser.A piezoelectric transducer (PZT) and EFPI sensor contrast measurement system is designed using needle-plate electrode to produce partial discharge.Results show that the sensitivity of EFPI sensor is determined by response frequency and static pressure sensitivity of EFPI.Design method of EFPI diaphragm is improved,and an EFPI sensor which has the same sensitivity as PZT for partial discharge detection is designed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 406002 (2015)
Research on Random Errors of Fiber Optic Gyro Based on Dynamic Allan Variance and Algorithm Improvement
Zhang Qian, Wang Wei, Wang Lei, and Gao Pengyu
In order to comprehensively understand the characteristics of random drift of fiber optic gyro (FOG) varying with time, the characteristics of the random error terms of FOG utilizing the dynamic Allan variance (DAVAR) method are studied. The results show that, the DAVAR not only can accurately assess each error of FOG,In order to comprehensively understand the characteristics of random drift of fiber optic gyro (FOG) varying with time, the characteristics of the random error terms of FOG utilizing the dynamic Allan variance (DAVAR) method are studied. The results show that, the DAVAR not only can accurately assess each error of FOG, but also can directly reflect the error stability of FOG. As the DAVAR needs to estimate the Allan variances at all time points, the computational time of the DAVAR grows very quickly with the increase of the analyzed time series. In order to solve the problem, a improved fast DAVAR algorithm based on the choice of relevant time t for the computation of the DAVAR is proposed. The results show that the improved fast DAVAR algorithm dramatically reduces the computational time without affecting operation results..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 406003 (2015)
Simultaneous Transfer of Time and Frequency Over 100 km Fiber Link
Wang Lingdong, Wu Guiling, Shen Jianguo, Hu Liang, Li Xinwan, and Chen Jianping
A simultaneous transfer scheme of time and frequency over optical fiber is presented. High- stable frequency transfer is realized by adopting the active phase noise compensation method based on the temperaturecontrolled fiber delay line and the piezoelectric ceramics transducer (PZT) delay line. At the same time, high A simultaneous transfer scheme of time and frequency over optical fiber is presented. High- stable frequency transfer is realized by adopting the active phase noise compensation method based on the temperaturecontrolled fiber delay line and the piezoelectric ceramics transducer (PZT) delay line. At the same time, high precision two-way time transfer using bidirectional time division multiplexing transmission is carried out on the stable optical fiber link through wavelength division multiplexing technology. A simultaneous transfer of time and frequency over 100 km fiber is demonstrated. The results show that the frequency transfer can reach stabilities of 5.25 × 10-14 at 1 s and 1.9 × 10-17 at one day，and the time transfer can reach stabilities of 40 ps at 1 s average time and 1.5 ps at 1000 s average time. The peak-peak value and standard deviation of the two-way time transfer are below 400 ps and 45 ps, respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 406004 (2015)
Fiber-Optic Humidity Sensing Based on Graphene
Xiao Yi, Zhang Jun, Cai Xiang, Tan Shaozao, Chen Zhe, Yu Jianhui, Lu Huihui, Liao Guozhen, Li Shiping, Tang Jieyuan, and Luo Yunhan
A novel fiber-optic humidity sensor is fabricated by using a side-polished fiber (SPF) coated with a film of reduced graphene oxide (rGO). The sensor can achieve power variation of up to 6.9 dB in the high humidity range [the relative humidity (RH) is 70% to 95% ], and display linear response with correlation coefficieA novel fiber-optic humidity sensor is fabricated by using a side-polished fiber (SPF) coated with a film of reduced graphene oxide (rGO). The sensor can achieve power variation of up to 6.9 dB in the high humidity range [the relative humidity (RH) is 70% to 95% ], and display linear response with correlation coefficient of 98.2% , sensitivity of 0.31 dB/(%RH), response speed of faster than 0.13 (%RH)/s, and good repeatability in RH from 75% to 95%. Theoretical analysis of sensing mechanism can explain the experimental results, and reveal the broad applying prospect of the sensor for other kinds of chemical vapor detections. Relying on novel sensing mechanism, this graphene-based optical sensor provides a beneficial complement to graphene-based electrical chemical ones, and can promote the employment of graphene in chemical sensing techniques..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 406005 (2015)
Low-Loss Coupling Between Photonic Crystal Fibers and Standard Single-Mode Fibers Based on Air Holes Filling
Zhang Jing, Jiang Haiming, Xie Kang, and Wang Erlei
A low-loss coupling between photonic crystal fibers and standard single-mode fibers based on air holes filling is proposed.The impacts of filling parameters on coupling loss between the two kinds of fibers is investigated by numerical simulations via beam propagation method.The results show that this method can greatlyA low-loss coupling between photonic crystal fibers and standard single-mode fibers based on air holes filling is proposed.The impacts of filling parameters on coupling loss between the two kinds of fibers is investigated by numerical simulations via beam propagation method.The results show that this method can greatly reduce the coupling loss between two kinds of fibers provided the filling parameters are selected appropriately.This method is usable for the coupling between a variety of photonic crystal fibers and single mode fibers especially for those with large mismatch of mode field diameters..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 406006 (2015)
Method of Multi-Wavelength Duobinary-Carrier-Suppressed-Return-to-Zero Optical Packets Generation
He Binbin, Ling Yun, Liao Lidan, Shen Suqi, Qiu Kun, and Zheng Mian
In order to simplify the transmitter structure of the multi-wavelength optical packets switching system, a method of multi-wavelength optical packets generation based on Mach-Zehnder delay interferometer (MZDI) is proposed. Only one MZDI is used to transform the payload format from wavelength division multiplexing (WDMIn order to simplify the transmitter structure of the multi-wavelength optical packets switching system, a method of multi-wavelength optical packets generation based on Mach-Zehnder delay interferometer (MZDI) is proposed. Only one MZDI is used to transform the payload format from wavelength division multiplexing (WDM) differential phase shift keying (DPSK) to WDM duobinary- carrier- suppressed- return- to- zero (DCS- RZ), meanwhile, couple the WDM non-return-to-zero (NRZ) label with the WDM payload and produce the WDM DCSRZ optical packets at the output of MZDI. A simulation of 4 × 40 Gb/s DCS- RZ optical packets is generated, transmitted into fiber and then separated into the label and payload. Detection is performed to verify the feasibility of this method. The simulation results show that after 240 km fiber transmission, the power penalty of the payload after the separation using Fabry-Perot (F-P) filter is only 1.8 dB..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 406007 (2015)
Holography
Deconvolution in Digital Holographic Reconstruction for High-Accuracy Position of Microsphere Tracking Technology
Lei Hai, Chang Xinyu, Xie Xiangjun, Zeng Yanan, Hu Xiaodong, and Hu Xiaotang
High resolution three-dimensional (3D) position of microspheres tracking is the key point in the aero of single molecule force spectrum. Digital holography is emerging as a promising optical technique for 3D microspheres tracking. A sequence of holograms are acquired using charge couple device with an in-line digital hHigh resolution three-dimensional (3D) position of microspheres tracking is the key point in the aero of single molecule force spectrum. Digital holography is emerging as a promising optical technique for 3D microspheres tracking. A sequence of holograms are acquired using charge couple device with an in-line digital holographic microscopy. Each hologram is subsequently reconstructed with Rayleigh-Sommerfeld propagation function and then deconvolved it with its propagator to suppress the artifacts and blur. Also polynomial fitting is introduced to fit the intensity profile of the volumetric reconstruction in the Z direction which can improve the resolution of 3D microspheres tracking. As a result, this method can measure multiple microspheres simultaneously and also can measure the overlapped spheres. The resolution in the Z direction is approach 2 nm, this is significant to the study of single biological molecule dynamics and particles image velocimetry etc..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 409001 (2015)
Image Processing
Research of Multi-Source Water Remote Image Fusion Algorithm Based on Bio-Optical Model
Guo Yulong, Wang Yongbo, Li Yunmei, Wang Qiao, Zhu Li, and Lü Heng
Lacking of proper data source is becoming a problem for inland lake water environment remote sensing monitoring. To solve this problem, a bio- optical fusion (BOF) algorithm to merge multiband image and hyperspectral image of complex inland case 2 water is developed. The performance of the BOF algorithm is verified basLacking of proper data source is becoming a problem for inland lake water environment remote sensing monitoring. To solve this problem, a bio- optical fusion (BOF) algorithm to merge multiband image and hyperspectral image of complex inland case 2 water is developed. The performance of the BOF algorithm is verified based on the bio-optical model of water body and traditional image fusion algorithm, by a Hyperion simulated dataset and compared with that of wavelet transform algorithm, Gram-Schmidt transforms algorithm, and color normalized algorithm. The results show that from the visual effect, the BOF algorithm has a better fusion of the color information of hyperspectral image and the detailed spatial information of the multispectral image. From the image evaluation indexes, the BOF algorithm gets the best performance under various resolution differences, and is not sensitive to the resolution difference; in the estimation experiment of chlorophyll- a concentration, the BOF algorithm also gets the best result, the root mean square deviation (RMSE) is 9.817, meanwhile, RMSE of the other three algorithms are 18.841,15.913 and 15.655. The proposed algorithm has strong potential applications, and expected to provide better data source for inland case 2 water remote sensing monitoring..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 410001 (2015)
Motion Detection and Image Restoration Based on Video Reconstruction from a Single Coded Exposure Photograph
Tang Chaoying, Chen Yueting, Li Qi, Feng Huajun, and Xu Zhihai
A motion detection and image restoration method based on video reconstruction from a single coded exposure photograph is proposed. The exposure time of each pixel in the sampling regions is modulated respectively, and a serial of video frames are reconstructed from the coded exposure image of each region. By using the A motion detection and image restoration method based on video reconstruction from a single coded exposure photograph is proposed. The exposure time of each pixel in the sampling regions is modulated respectively, and a serial of video frames are reconstructed from the coded exposure image of each region. By using the frames of the videos, displacement vectors and point spread function are calculated, and used to restore the blurred image finally. The proposed approach needs no additional devices and has advantages in both systematic complexity and cost. The effectiveness of the proposed method is experimentally confirmed by the results of simulation on problems of motion detection and image restoration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 410002 (2015)
Adaptive Nonuniformity Correction for Infrared Images Based on Temporal Moment Matching
Leng Hanbing, Yi Bo, Xie Qingsheng, Tang Li′nao, and Gong Zhendong
The response nonuniformity of uncooled infrared focal plane arrays is very similar to the stripe noise. Scene-based nonuniformity correction algorithm is an effective way to enhance the image quality and compensate the response drift. Based on the study of moment matching theory, a novel temporal moment matching nonuniThe response nonuniformity of uncooled infrared focal plane arrays is very similar to the stripe noise. Scene-based nonuniformity correction algorithm is an effective way to enhance the image quality and compensate the response drift. Based on the study of moment matching theory, a novel temporal moment matching nonuniformity correction algorithm is proposed. In the proposed algorithm, changing column is identified by the adjacent frames after moment matching, the correction coefficients are updated adaptively in temporal domain. The experimental results with the real infrared video sequences have shown that the proposed algorithm can significantly increase the convergence speed and reduce the ghosting artifacts..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 410003 (2015)
Underwater Laser Image Segmentation Method based on Adaptive Pulse Coupled Neural Networks
Wang Bo, Wan Lei, Li Ye, and Zhang Tiedong
Range gated underwater laser imaging technology, which has broad application prospects in oceanic research, deep sea exploration and under water operation field, is one of the most effective methods to decrease the backward scattering effect of water medium. However, the special features of underwater laser images, sucRange gated underwater laser imaging technology, which has broad application prospects in oceanic research, deep sea exploration and under water operation field, is one of the most effective methods to decrease the backward scattering effect of water medium. However, the special features of underwater laser images, such as speckle noise and non-uniform illumination, bring great difficulty for image segmentation. By analyzing the formation principle of speckle noise, an effective underwater laser image segmentation method is proposed. On the basis of noise response and intensity distribution, the proposed method determines the certain key parameters of neurons adaptively, while suppesses the behavior of neurons located in speckle noise. A gradient descent algorithm based on criterion of maximum two-dimensional Renyi entropy is applied to determine the dynamic threshold of neurons. Experimental results demonstrate that the method is significantly superior to Normalized Cut, fuzzy C means, mean shift and watershed methods, while the consumed time of this method is about one-fifth of conventional pulse coupled neural networks..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 410004 (2015)
Multispectral and Panchromatic Image Fusion Based on Improved Projected Gradient NMF in NSST Domain
Wu Yiquan, and Tao Feixiang
For the effective combination of spectral information of multispectral image with spatial detail information of panchromatic image, and further improvement in the quality of fused multi-spectral image, a fusion method of multispectral and panchromatic images based on improved projected gradient non-negative matrix factFor the effective combination of spectral information of multispectral image with spatial detail information of panchromatic image, and further improvement in the quality of fused multi-spectral image, a fusion method of multispectral and panchromatic images based on improved projected gradient non-negative matrix factorization（NMF）and improved pulse coupled neural network（PCNN）in non-subsampled shearlet transform （NSST）domain is proposed. Intensity hue saturation (IHS) transform is performed for multispectral image. The histogram of panchromatic image is matched to the histogram of intensity component of multispectral image, and the contrast of panchromatic image is enhanced. The intensity component of multispectral image and panchromatic image is decomposed by NSST, respectively. The low frequency image is obtained by fusion of two low frequency coefficients using improved projected gradient NMF. The spatial information of the fused image is further improved. For the fusion of high frequency sub-band coefficients, improved PCNN is adopted to enhance the image details. The fused intensity component is reconstructed by inverse NSST and the final fused image is obtained by inverse IHS transform. A large number of experimental results show that the proposed method enhance the spatial details in the fused image, while preserving spectral information of the multispectral image. And it is superior to the existing fusion methods such as the method based on IHS transform, the method of non-subsampled Contourlet transform (NSCT) combined with PCNN, and the method of NSCT combined with NMF..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 410005 (2015)
Imaging Systems
Rapid Nonlinear Distortion Correction of Aerial Optical Zoom Lens System
Zhou Qianfei, and Liu Jinghong
Concerned with the nonlinear distortion problems varying with the focal length of aerial optical zoom lenses, a rapid geometric correction method based on combining the offline calibration on the ground with the online correction on board is presented. The one- parameter division model is adopted to correct the radial Concerned with the nonlinear distortion problems varying with the focal length of aerial optical zoom lenses, a rapid geometric correction method based on combining the offline calibration on the ground with the online correction on board is presented. The one- parameter division model is adopted to correct the radial nonlinear distortion of lens. According to the perspective projection invariance of collinear points in template images, an optimization searching method of variant step length is adopted to estimate the optimal distortion coefficients and the distortion center coordinates of zoom lenses on the conditions of a few discrete focal lengths. The variation laws of the distortion parameters with the focal lengths are discussed by experiments finding, and the corresponding empirical formulas are established. In the actual flight test, the distortion parameters corresponding to the actual measured focal length value are calculated based on the empirical formulas to correct the lens distortion in the real scene images. Correction results of the template images and the real scene images show that this method can effectively correct the nonlinear distortion of zoom lenses. The average root mean square error of three 720 pixel×576 pixel images of template at different focal lengths is about 2.68 pixel, and the average correction time is 4.82 s. This correction method has the advantage of high efficiency, and easy to realize automatic correction for engineering applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 411001 (2015)
Depth Extraction Based on Function Fitting for Multiple Disparities in Integral Imaging
Wang Yu, and Piao Yan
Microlens array is used to record the information of space scenes in integral imaging system by only one imaging process. During the acquisition of the depth, the parameter setting and calibration of the camera is unnecessary, then the depth mesurement process is simplified, therefore the integral imaging has a great aMicrolens array is used to record the information of space scenes in integral imaging system by only one imaging process. During the acquisition of the depth, the parameter setting and calibration of the camera is unnecessary, then the depth mesurement process is simplified, therefore the integral imaging has a great advantage. However, due to the low resolution of the elemental images collected in system, the stereo matching between the elemental images is difficult to reach and susceptible to the recorded noise. Based on the advantage of integral imaging system can calculateand reconstruct multiple viewing images, make full use of the redundant information provided by the multiple viewing images to improve the stereo matching. An adaptive window with color similarity is utilized in the stero matching between the reference viewing image and other viewing images to obtain the disparity information. The function fitting for the multiple disparities of the reference viewing image is performed by considering the property that the disparity is proportional to the sampling distance between this pair of viewing images. This method can eliminate the mismatch resulting from factors such as the recording noise and make the discrimination more accurate between the depth levels of the object..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 411002 (2015)
Instrumentation, Measurement and Metrology
Absolute Testing of Null Lens Errors with Tilted Computer-Generated-Hologram
Zhu Deyan, Li Ming, Xue Donglin, and Zhang Xuejun
Aspheric surface testing always needs null lens, but the accuracy of the null lens are decided by the optical elements and the assemblage, and the accuracy and the feasibility of the null lens are unknown, and most of null lens need to be calibrated by tilted computer-generated-hologram (CGH). We introduce the principlAspheric surface testing always needs null lens, but the accuracy of the null lens are decided by the optical elements and the assemblage, and the accuracy and the feasibility of the null lens are unknown, and most of null lens need to be calibrated by tilted computer-generated-hologram (CGH). We introduce the principle of the null lens, and designe null lens to test aspherical surface, getting the simulation accuracy of the null lens which is 2.91 nm [root mean square (RMS)], and then design CGH to calibrate the null lens. Our initial results show that the accuracy of null lens is limited by the accuracy of optical elements and the assemblage. The simulation accuracy of null lens is 2.91 nm (RMS) and the actual accuracy is unknown. Though the calibrating of null lens, we can test the aspheric surface to 1.79 nm (RMS) surface errors, and also make sure the accuracy of null lens to test aspheric surface..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 412001 (2015)
Theoretical Modeling Analysis for Precise Space Ranging Based on Cross-Correlation of Femtosecond Optical Frequency Comb
Wang Guochao, Yan Shuhua, Yang Jun, Lin Cunbao, Wei Chunhua, and Du Zhiguang
The advent of femtosecond optical frequency comb (FOFC) offers many available solutions for absolute distance measurement,as is expected to be directly applied to many space ranging tasks,such as laser radar,satellite formation flying and gravity field measurement.With a purpose of precision requirement for future spacThe advent of femtosecond optical frequency comb (FOFC) offers many available solutions for absolute distance measurement,as is expected to be directly applied to many space ranging tasks,such as laser radar,satellite formation flying and gravity field measurement.With a purpose of precision requirement for future space ranging,an integrated method based on time of flight method and optical pulse cross-correlation analysis is proposed,making the distance traceable to the repetition rate of frequency comb.The fundamental model for laser ranging with FOFC is built,theoretical analysis for femtosecond pulse cross-correlation is implemented,and simulations for cross-correlation and large-scale ranging are demonstrated.The simulation result shows that when the target distance is near 10 km and the scanning precision for repetition rate is 0.01 Hz,the measurement accuracy is better than 450 nm within the linear test of a non-ambiguity range,and the peak-valley (PV) value of residual errors is less than 780 nm,validating that the proposed scheme is feasible for large-scale space ranging with submicron precision or even nanometer precision..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 412002 (2015)
Test and Uncertainty Analysis of Reference Source with Variable Polarization Degree and Large Dynamic Range
Kang Qing, Li Jianjun, Chen Ligang, Wu Haoyu, Yuan Yinlin, Meng Fangang, Zhai Wenchao, Qi Tao, and Zheng Xiaobing
A novel type of high precision reference source with variable polarization degree at large dynamic range(VPOLS-II) is introduced.The degree of linear polarization (DOLP) adjustment range of VPOLS-II varies from 0 to 0.72 within 0.46 mm to 2 mm.VPOLS-II produces linear polarization rays by four parallel glass plates.ThrA novel type of high precision reference source with variable polarization degree at large dynamic range(VPOLS-II) is introduced.The degree of linear polarization (DOLP) adjustment range of VPOLS-II varies from 0 to 0.72 within 0.46 mm to 2 mm.VPOLS-II produces linear polarization rays by four parallel glass plates.Through incorporating an integrating sphere and a beam expander system to guarantee the uniformity and parallelism of the outgoing beam,VPOLS-II generates rays with different DOLP through polarization state adjuster.DOLP values of VPOLS-II are tested.The calculated DOLP values of VPOLS-II and the measured ones by the spectropolarimetric analyzer (SPOLA) are compared and the factors influencing the uncertainty of DOLP are analyzed.The results show that the measured DOLP values of VPOLS-II are coincident with the theoretical ones within a 6 × 10-3 maximum difference when DOLP is less than 0.72.The combined uncertainty respectively is 8.8% ~0.936% and 0.936%~ 0.184% within DOLP of 0.01~0.09 and 0.09~0.72.This novel type of reference source meets the requirements polarimetric calibration in laboratory for polarized remote sensors and systematic performance test..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 412003 (2015)
Research on Phase-Shifting Characteristic of Retarder Array in Simultaneous Phase-Shifting Interferometer
Zheng Donghui, Chen Lei, Li Bo, Li Jinpeng, and Wulan Tuya
To study the phase- shifting characteristic of retarder array in simultaneous phase- shifting interferometry, the relationship between phase shift and fast-axis azimuth error is deduced through Jones vector and Jones matrix, and the error propagation formula is given. A spherical mirror is measured by simultaneous phasTo study the phase- shifting characteristic of retarder array in simultaneous phase- shifting interferometry, the relationship between phase shift and fast-axis azimuth error is deduced through Jones vector and Jones matrix, and the error propagation formula is given. A spherical mirror is measured by simultaneous phaseshifting interferometer based on retarder array without calibrating fast-axis azimuth accurately and Zygo GPI XP interferometer, the difference of root-mean-square and peak-to-valley are 0.003l and 0.033l respectively. The influence of azimuth error tolerance and phase shift error of retarder array and optical axis azimuth error of polarizer is discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 412004 (2015)
Integrated Optics
Er3+: ‘Water-free’ Fluorotellurite Glass Waveguides Written by Femtosecond Laser
Liu Shuang, Tang Wenlong, and Cheng Guanghua
By femtosecond laser with repetition rate of 1 kHz, central wavelength of 800 nm and pulse width of 120 fs, Type I (single line) and depressed circular cladding waveguides in Er3+ doped‘water-free’fluorotellurite glass are transversely written with slit shaping technology, respectively. The impact of the processing conBy femtosecond laser with repetition rate of 1 kHz, central wavelength of 800 nm and pulse width of 120 fs, Type I (single line) and depressed circular cladding waveguides in Er3+ doped‘water-free’fluorotellurite glass are transversely written with slit shaping technology, respectively. The impact of the processing conditions on the waveguides′ formation is systematically studied, and the waveguides with better guiding mode are obtained. Refractive index profile is reconstructed by intensity distribution of the near-field mode, and the largest positive refractive index change for Type I waveguide is about 1×10- 4, slightly smaller than that (1.9×10- 4) of depressed cladding waveguide. By using the scattering technique, the propagation loss of Type I waveguide is about 1.04 dB/cm. The loss of depressed cladding waveguide is less than 1.88 dB/cm by measuring insertion loss. Therefore, Er3+ doped ‘water-free’fluorotellurite glass waveguides inscribed by femtosecond laser are promising candidates for the development of integrated laser resources..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 413001 (2015)
Lasers and Laser Optics
Research on Pulse Echo Characteristic of Airborne Laser Detecting Air Target
Kou Tian, Wang Haiyan, Wang Fang, Chen Min, and Xu Qiang
By analyzing the effect of some factors to air target, the relation between the factors and laser pulse echo parameter has been studied.Considering the effect of distance, speed, entering angel and target size to the time delay and broadening of pulse, the relation model is built,and the main conclusion of the differenBy analyzing the effect of some factors to air target, the relation between the factors and laser pulse echo parameter has been studied.Considering the effect of distance, speed, entering angel and target size to the time delay and broadening of pulse, the relation model is built,and the main conclusion of the different effects of different factors to pulse time delay and broadening is obtained. Based on the discussion of the process of laser atmospheric tansmittance in the slant path, a calculating method of laser atmospheric slant transmittance is proposed, and the general model of energy attenuation of laser tansmittance is improved and the exponential decay of laser energy changing with the increase of distance and decreace of projection area is concluded. Based on the experiment system built,the measured echo datas are analyzed. Through calculating and comparing the theoretical result and measured result, the relative error is in 6% and it is a better coincidence, which has verified the effectiveness of built model. The conclusion has significant referenced value on the inverse of air target situation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 414001 (2015)
Chaotic Synchronization and Optimization of Semiconductor Ring Lasers
Xue Pingping, Zhang Jianzhong, Yang Lingzhen, and Zhang Zhaoxia
Synchronizations of semiconductor ring lasers are investigated numerically . When the frequency mismatch is -20GHz and the injection coefficient is greater than 2.5, the semiconductor ring lasers in two different configurations (open and closed loops) can all achieve good synchronizations with cross correlation coefficSynchronizations of semiconductor ring lasers are investigated numerically . When the frequency mismatch is -20GHz and the injection coefficient is greater than 2.5, the semiconductor ring lasers in two different configurations (open and closed loops) can all achieve good synchronizations with cross correlation coefficient above 0.95. The robustness of two schemes to frequency detuning with different injection coefficients are discussed and the results show the robustness of open loop structure are better than that of closed loop structure. The influences of internal parameters′ mismatches on the chaos synchronization are also studied. The synchronization of two structures can be optimized by choosing appropriate internal parameters. The correlation coefficient of closed loop increases from 0.96 to 0.99 (0.95 to 0.97 about open loop). At last the impacts of the feedback delay time and bias current on the synchronization in the closed loop structure are analyzed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 414002 (2015)
Light Field Modulation Induced by Spherical Inclusion in Fused Silica Subsurface
Tian Runni, Qiu Rong, Jiang Yong, and Zhou Qiang
A model of optics component damage induced by a spherical inclusion in fused silica illuminated by a laser beam is developed. Based on Mie scattering theory, scattering coefficients of several common kinds of inclusions are calculated, the light field distributions in the vicinity of inclusions are simulated. Light intA model of optics component damage induced by a spherical inclusion in fused silica illuminated by a laser beam is developed. Based on Mie scattering theory, scattering coefficients of several common kinds of inclusions are calculated, the light field distributions in the vicinity of inclusions are simulated. Light intensity enhancement factor (LIEF) as functions of refractive index and radius are analyzed. The results show that modulation effect of all kinds of inclusions can be ignored when the radius is smaller than 40 nm; when the radius of the particle is larger than 40 nm, for a non-dissipative particle with refractive index less than that of fused silica, LIEF increases with increasing radius and decreases with increasing refractive index, and the backscattering is much stronger than the forward scattering; when the refractive index is greater than that of fused silica, LIEF increase with the increasing radius and refractive index, and LIEF can reach to the order of 102 in some situations. For a dissipative particle, with the increase of radius, forward scattering intensity increases at first and then decreases. When the radius is larger than 170 nm，backscattering intensity is greater than forward scattering intensity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 414003 (2015)
Machine Vision
Fusing Multi-feature for Video Occlusion Region Detection Based on Graph Cut
Zhang Shihui, He Huan, and Kong Lingfu
To detect the occlusion region in video accurately, an occlusion region detection approach is proposed for video by fusing multi-feature based on graph cut. Three new occlusion related features named brightness patch match, maximal flow difference and flow residual are proposed based on the information of optical flow To detect the occlusion region in video accurately, an occlusion region detection approach is proposed for video by fusing multi-feature based on graph cut. Three new occlusion related features named brightness patch match, maximal flow difference and flow residual are proposed based on the information of optical flow and brightness, meanwhile their calculation methods are defined. The feature vector of each pixel is composed of the proposed features and is inputted into the random forest classifier to obtain the occlusion related information about pixels and adjacent pixel pairs. An occlusion detection energy function, which transforms the occlusion detection problem as an optimization one, is constructed by synthesizing the above occlusion related information. An undirected graph is constructed according to the energy function, then the energy function is solved by graph cut theory to gain the final occlusion region detection result. The experimental results show that, compared with the existing advanced methods, the proposed approach has higher accuracy and better real-time performance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 415001 (2015)
Materials
Enhancing the Mid-infrared Fluorescence Emission by Designing Photonic Crystals
Zhang Jun, Zhang Peiqing, Niu Xueke, Dai Shixun, Zhang Wei, Wang Xunsi, and Nie Qiuhua
Rare earth doped chalcogenide glasses is an important way to achieve mid- infrared luminescence. By designing photonic crystal structure on the sample, the luminous efficiency of the glass can be enhanced greatly. Tm3 + doped chalcogenide glass is prepared and the related optical properties are tested. Photonic crystalRare earth doped chalcogenide glasses is an important way to achieve mid- infrared luminescence. By designing photonic crystal structure on the sample, the luminous efficiency of the glass can be enhanced greatly. Tm3 + doped chalcogenide glass is prepared and the related optical properties are tested. Photonic crystal structure on the glass sample is designed to enhance the emission of 3.73 mm fluorescence which generated by the transition of Tm3 + ions. Finite difference time domain (FDTD) simulation shows that the photon density of states at 3.73 mm is greatly enhanced in the sample with designed photonic crystal, the Purcell amplification factor can be over 50 times than that in the bulk sample. This greatly increment of the photon density of states and the Purcell factor provides a theoretical basis for the enhancement of luminescence. The results of this work can be used to achieve high efficiency infrared light source device..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 416001 (2015)
Research of Slow Light Performances of Photonic Crystal Coupled Resonator Optical Waveguides Formed by Oval Rods Cavities
Li Changhong, Wan Yong, and Mao Qiangming
Slow light propagation and improved performance buffering properties are obtained from photonic crystal coupled resonator optical waveguides formed by enlarged and oval rods surrounded cavities. As the radius of bulk circular rods is 0.25a (a is a lattice constant) and radius of enlarged rods is 0.35a, the group velociSlow light propagation and improved performance buffering properties are obtained from photonic crystal coupled resonator optical waveguides formed by enlarged and oval rods surrounded cavities. As the radius of bulk circular rods is 0.25a (a is a lattice constant) and radius of enlarged rods is 0.35a, the group velocity of guided mode less than 2.37×10-4c (c is the light speed in the vacum) is obtained. Compared with that in homogeneous rods cavity waveguide, the maximum group velocity decreases one order magnitude. Simultaneously, buffer capacity decreases as well. Considering the buffer performances, the enlarged rods are developed into ovals to further improve the slow light properties and buffer performances. When the long axis of oval rods is 0.42a and short axis is 0.20a, the group velocity of guided mode less than 2.3053 × 10- 4c is obtained, and the buffer capacity arrives at 9.8214 bit. Q factor also reaches the maximum value 3575.1..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 416002 (2015)
Optical and Magneto-Optical Properties in a Sandwiched Structure Containing Co6Ag94
Dong Lijuan, Liu Yanhong, Liu Lixiang, and Shi Yunlong
The transmission and magneto-optical Faraday rotation effect are studied in a sandwiched structure containing the magneto-optical metal Co6Ag94 by tunneling mechanism. The double transmission peaks and single transmission peak are discussed in the sandwiched structure, respectively. The results show that the transmissiThe transmission and magneto-optical Faraday rotation effect are studied in a sandwiched structure containing the magneto-optical metal Co6Ag94 by tunneling mechanism. The double transmission peaks and single transmission peak are discussed in the sandwiched structure, respectively. The results show that the transmission and magneto-optical Faraday rotation effect of both double transmission peaks and single transmission peak in the sandwiched can simultaneously be enhanced due to the slow wave effect of the localized electromagnetic fields at the interface between the magneto-optical metal layer and the magnetophotonic crystals. In addition, Faraday rotation angle -45° is given in our sandwiched when the magneto-optical metal Co6Ag94 is gained. This property provides a theoretical basis for the design of compact magneto-optical isolation devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 416003 (2015)
Effects on Imaging Quality of Defects in the Photonic Crystal with Negative Refraciton Material
Liu Fengfang, Zhu Zhaojie, and Tong Yuanwei
Silicon columns are arranged periodically to constitute a photonic crystal slab with hexagonal structure in the air medium, and different configurations of defects are introduced in the photonic crystal slab. The effects on imaging quality are mainly discussed by changing the radius of the defect dielectric column and Silicon columns are arranged periodically to constitute a photonic crystal slab with hexagonal structure in the air medium, and different configurations of defects are introduced in the photonic crystal slab. The effects on imaging quality are mainly discussed by changing the radius of the defect dielectric column and the center position of defects. Through the method of finite difference time domain, simulation results show that the change of dielectric column radius and the position of defects can increase the transmittance of light and enhance the image intensity. Due to the introduction of defects, the interference between the defects can reduce the resolution of the imaging..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 416004 (2015)
Medical Optics and Biotechnology
Research on Point Spread Function Phantom Fabrication and Application for Evaluating Resolution Performance of OCT Systems
Hu Zhixiong, Hao Bingtao, Liu Wenli, and Hong Baoyu
Microsphere embedded phantoms are widely used to characterize point spread functions (PSF), which are generally employed to evaluate resolution performance of optical imaging systems such as optical coherence tomography (OCT). A convenient method based on surface silanization of silicon wafer is employed to prepare poiMicrosphere embedded phantoms are widely used to characterize point spread functions (PSF), which are generally employed to evaluate resolution performance of optical imaging systems such as optical coherence tomography (OCT). A convenient method based on surface silanization of silicon wafer is employed to prepare point spread function phantoms by mixing 1 μm in diamter polystyrene microspheres with transparent polymer-polydimethylsiloxane (PDMS). Compared to conventional methods employing moulding and polishing, the rapid prototyping process based on PDMS provides a faster, less expensive alternative. Detailed fabrication procedures as well as specific designs are described, and the produced PSF phantoms are utilized for performance assessment of a spectral domain OCT system. By analyzing the point spread functions, 6.8 μm axial resolution and 14.3 μm lateral resolution are obtained and in good agreement with the theoretically predicted values. For comparison, images of the standard-size microspheres are provided by measuring the PSF phantoms with optical microscope..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 417001 (2015)
Optical Design and Fabrication
Optical Design of Space-Based Scanning Tomographic Limb Imaging Spectrometer
Xue Qingsheng
Space-based scanning tomographic limb imaging spectrometer is demanded urgently by space atmospheric remote sensing. Based on the research objective of spaced-based scanning tomographic limb imaging spectrometer with wide horizontal covering range and minor volume and mass, An optical system of space-based scanning tomSpace-based scanning tomographic limb imaging spectrometer is demanded urgently by space atmospheric remote sensing. Based on the research objective of spaced-based scanning tomographic limb imaging spectrometer with wide horizontal covering range and minor volume and mass, An optical system of space-based scanning tomographic limb imaging spectrometer is designed using one dimension scanning mirror, off-axis parabolic telescope and aspheric grating spectral imaging system. The field of view of hyspectral imager is 0.75°×0.017°, relative-aperture is 1/1.8, and working waveband is from 280 nm to 800 nm. Ray tracing, optimization are performed by CODE V software. The root mean square (RMS) spot diameter for different wavelengths is less than 34 mm for aspheric grating spectral imaging system. The spectral resolution is 0.84 nm, which satisfies the requirement of specification (≤1.2 nm). The modulaiton transfer function (MTF) for different wavelengths of imaging spectrometer is more than 0.57 at characteristic frequency in the spatial direction. The design results satisfy the requirements of imaging quality, which is suitable for the application of space-based remote sensing..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 422001 (2015)
Source Optimization Using Particle Swarm Optimization Algorithm in Optical Lithography
Wang Lei, Li Sikun, Wang Xiangzhao, Yan Guanyong, and Yang Chaoxing
An efficient source optimization method using particle swarm optimization algorithm is proposed.The fidelity is adopted as the fitness function.Sources are encoded into particles,and then optimization is implemented by updating the velocities and positions of these particles.This method is demonstrated by using two typAn efficient source optimization method using particle swarm optimization algorithm is proposed.The fidelity is adopted as the fitness function.Sources are encoded into particles,and then optimization is implemented by updating the velocities and positions of these particles.This method is demonstrated by using two typical mask patterns,including a periodic array of contact holes and a complex pattern with cross gate design.The pattern errors are reduced by 66.1% and 27.3%,respectively.The results show that the proposed method leads to faster convergence than the source optimization method using genetic algorithm while improving the image quality at the same time.The robustness of the proposed method is also verified by adding aberrations and defocus respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 422002 (2015)
Optical System Design of a Co-Path Doppler Asymmetric Spatial Heterodyne Interferometer with Two Fields of View
Fei Xiaoyun, Feng Yutao, Bai Qinglan, Xie Nian, Li Yong, Yan Peng, and Sun Jian
A co-path Doppler asymmetric spatial heterodyne spectroscopy (DASH) interferometer with two fields of view to apply to wind vector observations from satellite is presented.The instrument using mirrors as field combiners,K?sters prism as beam splitter,one grating and imaging lens with focal power in one dimension can obA co-path Doppler asymmetric spatial heterodyne spectroscopy (DASH) interferometer with two fields of view to apply to wind vector observations from satellite is presented.The instrument using mirrors as field combiners,K?sters prism as beam splitter,one grating and imaging lens with focal power in one dimension can observe winds at different elevations in two orthogonal look directions.It is compact,without moving parts and efficient.An exact relation of the path offset Dd to Littrow angle and the size of K?sters prism is derived.A system for observation of the O[1D]630 nm emission form satellite is designed to show the process and result of parameters optimizing.Finally,a simulated result for the system indicate that the co-path DASH interferometer with two fields of view has space resolution ability in one dimension,it can get the interferograms at different elevations in two directions without scanning parts and it is possible to obtain the wind vector for the same volume with the help of satellite′s moving..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 422003 (2015)
Hollow Beam Generated by Incoherent Light Source and Multimode Fiber
Li Pan, Zhu Qingzhi, and Wu Fengtie
A method of generating hollow beam by incoherent monochromatic light emitting diode (LED) light source and multimode fiber is proposed. It is demonstrated that the hollow beam can be obtained by coupling a LED light source into a multimode fiber with a suitable incident angle. The transmission path of beam in multimodeA method of generating hollow beam by incoherent monochromatic light emitting diode (LED) light source and multimode fiber is proposed. It is demonstrated that the hollow beam can be obtained by coupling a LED light source into a multimode fiber with a suitable incident angle. The transmission path of beam in multimode fiber and the mechanism of producing hollow beam are analyzed. The simulation model is set up by software Zemax. The experimental system generating hollow beam by LED and multimode fiber is compared with a laser source. The results show that the uniformity of hollow beam obtained by using LED light source is better..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 422004 (2015)
Optical Design of High Resolution Two Dimension Echelle Spectrometer
Zhang Yufeng, Wu Jianfen, Zhu Qingsong, Du Hui, Wang Yu, and Wang Taishen
The dense grooves grating and long camera focus are usually used to obtain high optical resolution in traditional Rowland and Czerny-Turner spectrometers.To avoid expensive cost or large volume of spectrometers,a novel optical system based on echelle and low dispersion prism with high optical resolution is presented.FiThe dense grooves grating and long camera focus are usually used to obtain high optical resolution in traditional Rowland and Czerny-Turner spectrometers.To avoid expensive cost or large volume of spectrometers,a novel optical system based on echelle and low dispersion prism with high optical resolution is presented.Firstly,the principle and application method of echelle are deduced in details.Secondly,the design steps are provided to set up a optical system with echelle.Finally,an optical system example based on echelle grating is designed.Its camera focus is 400 mm with wavelength range of 180~800 nm,the spectrograph can be imaged on the two dimension area at the same time .The ray tracing and optimization to the optical system are carried out with Zemax software,and the results show the encircle energy in a single CCD pixel (24 mm×24 mm) area can reach 50%~70% above within wavelength range of 180~800 nm,the resolution is 0.00675 nm at 200 nm,and it is enough to meet applications of distinguishing most elements..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 422005 (2015)
Super Compact Optical System Design Based On Single Lens
Yu Linyao, Xie Jingjiang, Wei Qun, Zhang Tianyi, Wang Chao, Zhu Ruifei, and Jia Hongguang
In order to solve the problems when the R-C reflect IR system and the stability of the second mirror is installed, a compact integer structure is presented. The front and rear surface of lens are machined. Then inner reflect films are coated on two surfaces. At last the two mirrors are assembled in one lens which makesIn order to solve the problems when the R-C reflect IR system and the stability of the second mirror is installed, a compact integer structure is presented. The front and rear surface of lens are machined. Then inner reflect films are coated on two surfaces. At last the two mirrors are assembled in one lens which makes the installation of the two mirrors easier and the structure of the second mirror more stable. Reflection and antireflection films are coated on different surfaces respectively. Then two reflective surfaces and two transmission surfaces are produced on single lens. The entire optical system is integrated on a lens. It can not only effectively reduce system complexity and the difficulty of alignment, but also improve the stability and reliability of the system. A design of medium wave infrared (MWIR) compact optical system is presented. It has good imaging capability with modulation transfer function (MTF) of all field of view more than 0.55 which is very close to the diffraction limitation. The optics system realizes athermal between -40 ℃~60 ℃by binary diffractive optical element. Finally a real lens is manufactured by a single point diamond turning machine and imaging experiments is carried out at different temperatures. The results show that the optical system performance well without defocus. The system meets the actual processing and application requirements..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 422006 (2015)
Optical System Design for Infrared Target Simulator
Song Yansong, Yang Jianfeng, Zhao Yiyi, Yan Xingtao, and Ma Xiaolong
A new common-path scheme for infrared target simulator is proposed in order to simplify the structure of infrared target simulator.Based on this scheme,a dual-channel infrared projection system with compacted structure is designed.The optical system is characterized by the system field angle of ±3°,the spectrA new common-path scheme for infrared target simulator is proposed in order to simplify the structure of infrared target simulator.Based on this scheme,a dual-channel infrared projection system with compacted structure is designed.The optical system is characterized by the system field angle of ±3°,the spectral band of 3~5 mm,the entrance pupil distance of 550 mm,the focal length of 220 mm and the F number of 3.67.After analyzing the reason why the structure of the previous infrared target simulator is complex and the influence of different forms of interference target simulator structure on the design of common-path system,a good solution is given with combination of blackbody source and scanning mirror as interference target source.Through theoretical study of the influence of scanning mirror on the system performance,the feasibility of this scheme is proved.The results show that the modulation transfer function of the main target channel is better than 0.5 at the field of 16lp/mm,the root mean square (RMS) radius of each channel is less than 18 mm,and the distortion is less than 1%.The system can meet the requirements of minus 10 ℃ to 40 ℃ working environment by focusing..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 422007 (2015)
LED Street Lamp Lens with High Energy Efficiency Utilization Based on Reverse Optimization Design
Yan Wenping, Guo Zhenning, Lin Jieben, Gan Ruting, Lin Muchuan, Pan Shifa, and Liao Xuan
To improve the quality and energy efficiency of road lighting, the reverse optimization design method is employed to design a light-emitting diode (LED) street lamp lens. By taking the road lighting standard as constraint, an ideal light intensity distribution with maximum brightness illumination ratio is optimized andTo improve the quality and energy efficiency of road lighting, the reverse optimization design method is employed to design a light-emitting diode (LED) street lamp lens. By taking the road lighting standard as constraint, an ideal light intensity distribution with maximum brightness illumination ratio is optimized and obtained. Based on the optimized ideal light intensity distribution, the freeform surface is established by using the variable separation mapping method. The light source and target plane are meshed to form the mapping relationship, and the surface structure error is controlled as well. Then the lens is optimized by using feedback optimization to make the intensity distribution of lens close to ideal light intensity distribution. Simulation experiment results show that the lens designed by the proposed method conforms to the road lighting standard well, and the brightness illumination ratio is 0.067. Compared with traditional symmetry light intensity distribution, energy consumption is reduced to 20.2% . The high quality lighting and energy utilization ratio of LED street lamp are realized finally..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 422008 (2015)
Optical Devices
All-Polymer Athermal Low Polarization-Independent 49-Channel Arrayed Waveguide Grating
Li Hao, Gu Yunlong, Zheng Yang, Chen Changming, Wang Xibin, Yi Yunji, Sun Xiaoqiang, Wang Fei, and Zhang Daming
An athermal low polarization-independent 49-channel arrayed-waveguide grating (AWG) multiplexer relying on a ultraviolet (UV) curable all-polymer approach is designed and fabricated by simple direct ultraviolet photolithography process. The transmission properties of the AWG around the central wavelength of 1550.918 nmAn athermal low polarization-independent 49-channel arrayed-waveguide grating (AWG) multiplexer relying on a ultraviolet (UV) curable all-polymer approach is designed and fabricated by simple direct ultraviolet photolithography process. The transmission properties of the AWG around the central wavelength of 1550.918 nm with the wavelength spacing of 0.8 nm are optimized by Matlab programming. By properly adjusting the positive coefficient of thermal expansion of the polymer substrate and the negative thermo-optic coefficient of the polymer waveguide, athermal and low polarization-independent characteristics of AWG device are realized. The actual fiberfiber insertion loss at each channel is from 5.51 dB to 10.62 dB, and the crosstalk of the 49 channels is larger than 20 dB. Both polarization drifts and temperature shifts of the AWG are 0.08 nm and 0.03 nm/K, respectively. The new technique can be well suited for realizing optical integrated circuits with excellent performances..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 423001 (2015)
Analysis of the Mirror Surface Errors in a Michelson Interferometer
Feng Mingchun, Liu Wenqing, Xu Liang, Gao Minguang, Wei Xiuli, Tong Jingjing, Li Xiangxian, and Chen Jun
The effect on modulation depth caused by polish errors is analyzed from the interference principle of Michelson interferometer.The modulation depth cannot achieve ideally 100% due to surface errors, but the modulation depth cannot be below 90% in an ideal case. Through the analysis and discussion, it may be establishedThe effect on modulation depth caused by polish errors is analyzed from the interference principle of Michelson interferometer.The modulation depth cannot achieve ideally 100% due to surface errors, but the modulation depth cannot be below 90% in an ideal case. Through the analysis and discussion, it may be established that the surface errors should be plane to about λ/14 or better so that the modulation depth is not below 90% for satisfactory performance of the interferometer. At the same time, flatness for 5 mirrors is measured by Zygo interferometer so as to get peak to peak value and some other parameters.The flatness requirements of modulation depth is met according to the analysis of the measured results. Based on the study of the surface errors of the Michelson interferometer, it is a certain guiding significance to design, develop and analysis performance for an interference spectrometer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 423002 (2015)
Research for Light-Emitting Diode-Based Neonatal Jaundice Therapeutic Device Light Source
Gan Ruting, Guo Zhenning, Lin Jieben, Yan Wenping, Liao Xuan, Pan Shifa, and Lin Muchuan
In order to improve bilirubin degradation effect and neonatal jaundice phototherapy efficiency, a light source of light-emitting diode (LED)-based neonatal jaundice therapeutic device (NJTD) is designed and developed. The most efficient absorption spectrum of standard bilirubin in vitro tested by the experiment is regaIn order to improve bilirubin degradation effect and neonatal jaundice phototherapy efficiency, a light source of light-emitting diode (LED)-based neonatal jaundice therapeutic device (NJTD) is designed and developed. The most efficient absorption spectrum of standard bilirubin in vitro tested by the experiment is regarded as the target spectrum of NJTD light source. The commercial available monochromatic LEDs with different peak wavelengths and full width at half maximum (FWHM) are used as matching sources, and the simple genetic algorithm (SGA) is introduced as the spectral matching method. The spectral matching design is realized for the light source of the novel NJTD, and subsequently, the light sample model is developed, the corresponding spectrum is measured and the effect is analyzed finally. Results show that the fitted spectrum is in close proximity to the target spectrum with 97.62% matching degree, the spectrum of the light sample model developed is very comparable to the target spectrum with 93.08% matching degree，monochrome LEDs with narrow bandwidth can match the required target spectrum perfectly. The spectral matching degree is higher, which provides research foundation for the selection of LED-based NJTD light source..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 423003 (2015)
Remote Sensing and Sensors
Design and Manufacture of Space All-Purpose Double-Faced Reflective Mirror
Wang Yiqun, Wang Long, Guo Wancun, and Zheng Yuquan
Space all-purpose double-faced reflective mirror is a key optical component of a certain spaceborne hyper-spectral imager.Its design and manufacture technology are important problems which must be solved during the hyper-spectral imager engineering development phase.Firstly,the composing project of double-faced reflectSpace all-purpose double-faced reflective mirror is a key optical component of a certain spaceborne hyper-spectral imager.Its design and manufacture technology are important problems which must be solved during the hyper-spectral imager engineering development phase.Firstly,the composing project of double-faced reflective mirror,one face optical reflective surface and the other diffuse surface,is introduced.Furthermore,the structure design and finite element analysis of reflective mirror have been carried through taking into account ratio of diameter and thickness,lightweight form and mounting interface.Based on these works,the manufacture technology of double-faced reflective mirror has been explored,and then the mirror development has been finished.Finally,the double-faced reflective mirror testing devices and the mirror′s testing results are presented.The testing results indicate that root mean square values of the optical surface figure of double-faced reflective mirror is 0.023λ (λ =632.8 nm),the diffuse characteristic is close to the normative diffuser at vertical incidence.The results prove that the space all-purpose double-faced reflective mirror satisfies the requirements of hyper-spectral imager..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 428001 (2015)
Thermal Effect on Spectral-Line Shift of a Airborne Imaging Spectrometer
Xian Guang, Yan Changxiang, and Shao Jianbing
In order to study the thermal effect on spectral- line shift of aerial imaging spectrometer, the characteristics, mechanism and manifestation of the instrument temperature load airbrone environment are analyzed, and the spectral-line shift characteristics of the spectrometer are studied. According to the characteristicIn order to study the thermal effect on spectral- line shift of aerial imaging spectrometer, the characteristics, mechanism and manifestation of the instrument temperature load airbrone environment are analyzed, and the spectral-line shift characteristics of the spectrometer are studied. According to the characteristics of the temperature load in airbrone environment, the finite element method is taken to calculate the deformation and rigid body displacement of the mirror of the optical system at a temperature load, combined with the least squares method and coordinate transformation method. Ray tracing to the deformed optical system are carried out and its spectral-line shift characteristics are studied. The thermal-optical test and calibration test during flight is taken to prove the theoretical analysis. The results show that within the range of ±10 ℃, there is only shifting in the spectral direction, no tension or compression effects. During the calibration test of flight, the average line offset is 0.248 nm, satisfies the need of 1/3 of the accuracy (calibration accuracy is 1 nm). No further spectral calibration or correction is needed in the later imaging..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 428002 (2015)
Scattering
Research on Optical Scattering Characteristics of High Altitude Balloon in Near Space
Jing Nan, Li Chuang, and Zhou Nan
Optical scattering characteristics of high altitude balloon in near space are researched based on the fundamental radiation theory in applied optics. Facet of balloon in near space is created according to the general idea of coordination transformation and surface mesh-creation. A bidirectional scattering distribution Optical scattering characteristics of high altitude balloon in near space are researched based on the fundamental radiation theory in applied optics. Facet of balloon in near space is created according to the general idea of coordination transformation and surface mesh-creation. A bidirectional scattering distribution function (BSDF) model is deduced by summing transparent object all scattering components, including specular reflective, near-specular reflective, diffuse reflective and random diffuse reflective components. A mathematical model of scattering characteristics of balloon in near space is built. An atmospheric modeling tool, MODTRAN, is used to model background radiance in the range of 3~5 μm and 8~14 μm and radiance of balloon in the range of 0.24~2.4 μm . The results show that the high altitude balloon radiance is 2.28 × 10-3 W ∕(cm2·μm·sr) , whose calculation error is 10.6% in use of BSDF model, and relative to bidirectional reflection distribution function (BRDF) model, the accuracy has an improvement of 2%. The modeling method of scattering characteristics of balloon in near space agrees with the modeling results, which proves the correctness of mathematical model..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 429001 (2015)
Spectroscopy
Design of Real-Time Measurement of Atmospheric CO and CH4 Based on Tunable Diode Laser Spectroscopy System
Li Mingxing, Liu Jianguo, Kan Ruifeng, Yao Lu, Yuan Song, Dai Yunhai, Wei Min, Xu Zhenyu, and Ruan Jun
Tunable diode laser absorption spectroscopy (TDLAS) has a good prospect of application in rapid measurement of trace gases, due to its high resolution and high sensitivity. A real-time measurement system for atmospheric CO and CH4 based on open- path TDLAS is developed, which has a simple structure with direct absorptiTunable diode laser absorption spectroscopy (TDLAS) has a good prospect of application in rapid measurement of trace gases, due to its high resolution and high sensitivity. A real-time measurement system for atmospheric CO and CH4 based on open- path TDLAS is developed, which has a simple structure with direct absorption techniques, avoiding concentration calibration in wavelength modulation techniques. In the system, the data acquisition and processing is performed using a micro controller unit (MCU) of STM32, then the data is sent to DWIN graphical utilized software (DGUS), showing gas concentration and light intensity online, and the curves of gas concentration and light intensity versus time. The concentration and light intensity data is saved in the SD card. This system can replace the upper computer operation to achieve miniaturization. The system combining direct absorption method and a 2333 nm band laser is presented, and is utilized to monitor carbon monoxide and methane at Kexue Island of Hefei with 750 m optical path. The measurement result shows that the atmospheric CO concentration is lower than the CH4 concentration. The system has been tested for a long time to verify its stability, and its detection limit is 0.205 mg/m3 for CO and 0.181 mg/m3 for CH4..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 430001 (2015)
Spatial Resolution Measurement of Synchrotron Radiation Infrared Microspectroscopy Beamline
Zhu Huachun, Tong Yajun, Ji Te, Peng Weiwei, Zhang Zengyan, Chen Min, and Xiao Tiqiao
Infrared synchrotron radiation provides considerable brightness advantages over conventional infrared sources in a wide wavelength range, allowing the spatial resolution to reach the diffraction limit. Spatial resolution of BL01B1 infrared microspectroscopy beamline station in Shanghai Synchrotron Radiation Facility (SInfrared synchrotron radiation provides considerable brightness advantages over conventional infrared sources in a wide wavelength range, allowing the spatial resolution to reach the diffraction limit. Spatial resolution of BL01B1 infrared microspectroscopy beamline station in Shanghai Synchrotron Radiation Facility (SSRF) is tested. Step-edge method and resolution target bar method are used to measure the spatial resolution of the infrared microspectroscopy beamline BL01B1. The experimental results show that the spatial resolution of this infrared microspectroscopy beamline station and the diffraction limit theory are comparable in the middle infrared region..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 430002 (2015)
Thin Films
Accurate Determination of Optical Constants of Amorphous Absorbing Thin Films by Spectroscopic Ellipsometry
Li Jiang, Li Pei, Huang Feng, Wei Xianhua, Ge Fangfang, and Li Peng
Spectroscopic ellipsometry (SE) and spectrophotometer are used to measure the ellipsometric parameters (y and D ) and transmittance of ultrathin diamond like carbon (DLC) film and amorphous silicon (a-Si) film respectively. Accurate determination of optical constants and thickness of DLC film and a- Si film is a difficSpectroscopic ellipsometry (SE) and spectrophotometer are used to measure the ellipsometric parameters (y and D ) and transmittance of ultrathin diamond like carbon (DLC) film and amorphous silicon (a-Si) film respectively. Accurate determination of optical constants and thickness of DLC film and a- Si film is a difficult problem when ellipsometric parameters are used independently. It is due to the strong statistical correlation which exists between the optical constants and thickness of the film when these parameters are adjusted to fit the experimental ellipsometric parameters. By simultaneous fitting ellipsometric parameters and transmittance (SE+T), thickness and optical constants can be obtained easily and rapidly. However, noise, minor contamination on the film surface or any small absorption in the substrate will be mixed into the film′s optical constants. In order to determine the optical constants of ultrathin DLC and a-Si film accurately, the optical constants are parameterized by combining SE+T and optical constant parameterization approach. The results show that the adopted method is able to uniquely and accurately measure optical constants from a unique solution while maintaining smooth, continuous, and often Kramers-Kronig (K-K) consistent optical properties for the ultrathin DLC film and a-Si film. This method is expected to be of value for optical property measurement of other amorphous films with thickness of just a few tens of nanometers..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 4, 431001 (2015)
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