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2014
Volume: 34 Issue 10
51 Article(s)
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Atmospheric Optics and Oceanic Optics
Analysis of the Non-Local Thermodynamic Equilibrium Effect on Infrared Limb Radiances in the Upper Atmosphere
Tan Pengfei, Han Yuge, and Xuan Yimin
The local thermodynamic equilibrum (LTE) and non-LTE limb radiances in the upper atmosphere are calculated for the main infrared (IR) spectral regions by line-by-line radiative transfer model, which is reference forward model (RFM). According to the relative deviation, the non-LTE effect on IR limb radiance is analyzedThe local thermodynamic equilibrum (LTE) and non-LTE limb radiances in the upper atmosphere are calculated for the main infrared (IR) spectral regions by line-by-line radiative transfer model, which is reference forward model (RFM). According to the relative deviation, the non-LTE effect on IR limb radiance is analyzed under day and night conditions and the altitude range of application of the LTE is identified. The comparison of the limb radiance between day and night is presented. The analysis results show that the non-LTE and LTE IR limb radiances in the upper atmosphere have a significant deviation and solar pumping in the day can increase the deviation. There are significant differences in the limb radiances for some spectral bands between day and night. In addition to the CO2 4.3 μm spectral band in the day, there isn’t significant deviation between the non-LTE and LTE below 60 km for other spectral bands and it can reach about 80 km for CO2 15 μm spectral band. The results lay the foundation for further study of non-LTE model in the upper atmosphere..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1001001 (2014)
Research on Dual-Frequency Doppler Lidar Based on Fabry-Perot Etalon Quad-Edge Technique
Shen Fahua, Xia Yiqi, Yu Aiai, and Liu Chenglin
The dual frequency Doppler wind lidar based on Fabry-Perot (F-P) etalon quad-edge technique is studied. The principle of wind speed measurement by using F-P etalon four edges and two frequencies is analyzed briefly. The system structure of the dual frequency Doppler wind lidar based on F-P etalon quad-edge technique isThe dual frequency Doppler wind lidar based on Fabry-Perot (F-P) etalon quad-edge technique is studied. The principle of wind speed measurement by using F-P etalon four edges and two frequencies is analyzed briefly. The system structure of the dual frequency Doppler wind lidar based on F-P etalon quad-edge technique is decribed in detail. Several parameters, such as the two-frequency interval of outgoing laser, the incident beam divergence angle, the effective aperture of the etalon, and the reflectivity of etalon plates are optimized thoroughly. According to the selected system parameters, the detection performance of the Doppler lidar system is simulated. The simulation results show that on sunny weather conditions, within ±25 m/s radial velocity measurement dynamic range, the system can achieve 8 km height at nighttime and 6.5 km height at daytime when the laser elevation is 60°, the spatial and temporal resolution are 60 m and 1 min, to meet the radial wind velocity measurement error less than 2 m/s. The overall system performance at nighttime is significantly better than that of Doppler wind lidar system based on F-P etalon double-edge technique. Meanwhile, the system′s detection performance is greatly influenced by the sky background noise. Therefore, the system should be working during the day with a narrow bandwidth filter to improve the detection performance of the system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1001002 (2014)
High-Frequency Error Compensation Method for the Fast Fourier Transform-Based Turbulent Phase Screen
Xiang Jingsong
The fast Fourier transform (FFT)-based turbulence phase screen has the drawbacks of the undersampling of the low spatial frequency and high spatial frequency turbulence components. So a method is proposed to compensate the high frequency errors. In this compensation method, the phase autocorrelation matrix correspondinThe fast Fourier transform (FFT)-based turbulence phase screen has the drawbacks of the undersampling of the low spatial frequency and high spatial frequency turbulence components. So a method is proposed to compensate the high frequency errors. In this compensation method, the phase autocorrelation matrix corresponding to the unsampled high frequency power spectrum is calculated by numerical integration, and then the compensation values of the power spectrum on the sampling girds are obtained from the phase autocorrelation matrix by a FFT operation. The simulation results show that the high frequency error can be compensated accurately by this method, and the error of the simulated phase structure function is about 0.1%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1001003 (2014)
Analysis of the Radio on Free Space Optical Transmission Link for the Satellite-to-Ground Communication
Kang Zijian, Han Xiuyou, Li Cong, Xiao Yongxuan, Shi Nuannuan, Hu Shu, Hu Jingjing, Gu Yiying, and Zhao Mingshan
The radio on free space optical transmission (RoFSO) link is proposed to meet with the large capacity requirement of satellite-to-ground communication. With the established link model, the link optical loss, the output power of microwave signal, noise and the bit error rate (BER) under atmospheric turbulence channel arThe radio on free space optical transmission (RoFSO) link is proposed to meet with the large capacity requirement of satellite-to-ground communication. With the established link model, the link optical loss, the output power of microwave signal, noise and the bit error rate (BER) under atmospheric turbulence channel are deduced. The influence of bias voltage of the electro-optic modulator on the signal to noise ratio (SNR) and BER is simulated. The analysis results show that compared with the quadrature bias point, the optimal control of the bias voltage can improve the SNR and BER. And the effect of improvement increases with the decrease of the modulation coefficient. The research gives good foundation for the realization of RoFSO based satellite-to-ground communication system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1001004 (2014)
Detectors
Target Tracking Based on Particle Swarm Optimization Using Dynamic Pyroelectric Infrared Sensor
Wang Zebing, Yang Wei, and Qin Li
In infrared target tracking, the pyroelectric infrared (PIR)sensor can detect the relative direction of a thermal moving target through optical modulation, but cannot get its accurate distance. For this, a swarm intelligence search approach is proposed. At the swing state, PIR can feel the moving target, at the same tiIn infrared target tracking, the pyroelectric infrared (PIR)sensor can detect the relative direction of a thermal moving target through optical modulation, but cannot get its accurate distance. For this, a swarm intelligence search approach is proposed. At the swing state, PIR can feel the moving target, at the same time, the detection angle is recorded. By analyzing the relationship between the detection angle sequence and the discrete points of moving target trajectory in polar coordinates, finding that the target trace is determined by the polar radius sequence. Multi-dimensional polar diameter particle swarm optimization space is established. Meanwhile, a fitness function to evaluate the particle′s merits is proposed. The target trajectory can be obtained. The proposed method is an effective solution to enlarge the detection range and improve the accuracy of target tracking. Human body′s tracking experiment is performed. The average localization error is not more than 0.4 m. The findings demonstrate the effectiveness of the method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1004001 (2014)
Drift Compensation of Infrared Imaging System Using Ambient Temperature
Yu Yi, Wang Min, Chang Songtao, and Jiang Huilin
For radiation measurement using infrared imaging systems, gray value drift caused by ambient temperature variation is a significant source of error. By studying the effects of ambient temperature on the output gray value of cooled infrared systems, a drift compensation method is proposed. The sources of gray value drifFor radiation measurement using infrared imaging systems, gray value drift caused by ambient temperature variation is a significant source of error. By studying the effects of ambient temperature on the output gray value of cooled infrared systems, a drift compensation method is proposed. The sources of gray value drift are analyzed, and the relationship between drift and ambient temperature is derived to establish a theoretical model. A simple drift correction method is proposed. The radiometric calibration experiment is carried out for verification. The results indicate that proposed method can not only improve the measurement accuracy of the infrared imaging system, but also achieve drift compensation under arbitrary integration time, which improves the efficiency of radiometric calibration and measurement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1004002 (2014)
Calculation and Analysis of Detection Ability for Shipboard Star Sensor
Tong Shuai, Li Hui, and Wang Anguo
As an accurate independent navigation equipment, star sensor is widely used on different kinds of platform. The detection ability directly influences the efficiency and measurement accuracy of the star sensor. Shipboard star sensor works on the sea, which is different from the space, the detection ability is influencedAs an accurate independent navigation equipment, star sensor is widely used on different kinds of platform. The detection ability directly influences the efficiency and measurement accuracy of the star sensor. Shipboard star sensor works on the sea, which is different from the space, the detection ability is influenced not only by the parameters of the lens and the image sensor, but also by the night sky background and the atmosphere. In order to provide theoretical basis for research and application of shipboard star sensor, a calculation model of the detection ability for shipboard star sensor is deduced according to the study and analysis of star light propagation, imaging and signal extraction process, and the correctness of the model is verified by experiment. All the influencing factors are analyzed with the model. In the end, several suggestions on design and development of shipboard star sensor are proposed based on the analysis results..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1004003 (2014)
Fiber Optics and Optical Communications
Fiber Laser Output from Neodymium-Doped Phosphate Glass Fibers with Shaped Inner Claddings
Huang Yi, Li Wentao, Zhang Lei, Chen Danping, Chen Wei, and Hu Lili
D-shaped double cladding (DC) Nd3+-doped phosphate glass fiber with the core diameter of 20 μm is fabricated by the stacking technique and pumped by a commercial 793 nm laser diode. The maximum output power of 2.52 W at 1053 nm is generated, with the slope efficiency of 41.5% respects to the absorbed pump power. To invD-shaped double cladding (DC) Nd3+-doped phosphate glass fiber with the core diameter of 20 μm is fabricated by the stacking technique and pumped by a commercial 793 nm laser diode. The maximum output power of 2.52 W at 1053 nm is generated, with the slope efficiency of 41.5% respects to the absorbed pump power. To investigate the effect of inner cladding on fiber laser performance, hexagonal, eccentric and circular DC fibers are fabricated and analyzed with the same procedure as the D-shaped fiber. The results show that among all the DC fibers with different inner claddings, the D-shaped fiber has the highest pumping power absorption, which is beneficial to improve the fiber laser performance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1006001 (2014)
Polarization Bias Error Model and Simulation of Fiber-Optic Gyroscope with Double Optical Length
Xu Hongjie, Zhang Wenyan, Xu Xiaobin, Song Ningfang, and Hu Yongkang
The polarization error of optical system limits the accuracy of fiber-optic gyroscope with double optical length. In order to improve the precision, the models of optical devices and fused points in the new gyroscope are described by using coherent matrix and Jones matrix. Based on the model mentioned above and interfeThe polarization error of optical system limits the accuracy of fiber-optic gyroscope with double optical length. In order to improve the precision, the models of optical devices and fused points in the new gyroscope are described by using coherent matrix and Jones matrix. Based on the model mentioned above and interference analysis between secondary coupled wave-trains and principal wave-trains in the clockwise and counter clockwise direction, a physical model of polarization bias error of fiber-optic gyroscope with double optical length is established. With practical parameters setting, the influences of some apparatus on polarization noise are simulated and discussed, and furthermore, a new method of matching pigtails is especially presented, which can be used for decreasing the polarization error effectively. Simulation results demonstrate that the polarization bias error can be suppressed from 0.145°/h to less than 0.017°/h, and its peak-valley value of variation with temperature can be suppressed to less than 3×10-4°/h, through matching fiber length. The polarization bias error is suppressed effectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1006002 (2014)
Influence of Temperature on the Coupling Efficiency of Spatial Light into Single Model Fiber
Cao Guiyuan, Yang Yuqiang, Yu Jianjie, and Shen Tao
Environmental temperature is an important factor which influences the optical antenna system in orbit. When the temperature changes, the curvatures of the mirrors and the distances between lenses can vary, leading to the reducing of the coupling efficiency of spatial light into single model fiber. Assuming that temperaEnvironmental temperature is an important factor which influences the optical antenna system in orbit. When the temperature changes, the curvatures of the mirrors and the distances between lenses can vary, leading to the reducing of the coupling efficiency of spatial light into single model fiber. Assuming that temperature cannot change the imaging quality except for defocus, the model of influence of temperature on coupling efficiency is established for reflection-type antenna. Based on the model, the numerical simulation of the coupling efficiency is delivered. In order to verify the model, the related experiment is done. The results show that the calculated value is in agreement with the experimental results. When the temperature difference increases to 2 ℃, defocus value enhances to about 52 μm and the coupling efficiency reduces to about 10%. The results have an important contribution to the design of the optical receiving antenna of space optical communication..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1006003 (2014)
Geometric Optics
Research on Multi-Direction Collimation Beam on the Plane Parallel with LED Lighting Plane
Cheng Zhiming, Zeng Ping, Zhang Zhihai, and Hu Yan
Multi-direction collimation lens based on light emitting diode (LED) is proposed, the total internal reflection multi-freeform surface is employed to realize multi-direction collimation. Lambert type light distribution of LED is researched, and lens are used to change the light distribution. The coordinate value of poiMulti-direction collimation lens based on light emitting diode (LED) is proposed, the total internal reflection multi-freeform surface is employed to realize multi-direction collimation. Lambert type light distribution of LED is researched, and lens are used to change the light distribution. The coordinate value of points on freeform surface is calculated by Matlab software. Combined with the 3D software and TracePro software, multi-direction collimation lens are designed. Multi-direction collimation beams are in the same plane which is parallel with the light-emitting plane of LED. Each divergence angle of collimation beam is merely 3°..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1008001 (2014)
Image Processing
Color Image Fusion Framework Based on Improved (2D)2PCA
Xia Yu, and Qu Shiru
Aiming at the color distortions generated by color space conversion and the strong correlation in the red green blue (RGB) space during image fusion process. The fusion framework is proposed based on the improved two directional two dimensional principal component analysis [(2D)2PCA], which overtakes the shortcomings oAiming at the color distortions generated by color space conversion and the strong correlation in the red green blue (RGB) space during image fusion process. The fusion framework is proposed based on the improved two directional two dimensional principal component analysis [(2D)2PCA], which overtakes the shortcomings of PCA in catching image structure and reducing spectral information lost. Considering the structure of images in RGB space, the rows and columns of input images are set as the inputs of two 2DPCA approaches. The reconstruction weights of row and column directions are set linearly to the covariance. The PC replacemet is based on the structure properties of the reconstruction. The fusion is built by weighting reverse transformation of covariance. To verify the effectiveness of the proposed method, two experiments are discussed. One experiment uses the high resolution grey image and its responding blurred color image as source images, the other experiment is built on the visual color image and the infrared image. Experimental results show the superior of the proposed method over previous works with respect to the spatial resolution as well as other fusion indicators..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1010001 (2014)
SAR and Visible Image Enhanced Fusion Based on Texture Segmentation and Top-Hat Transformation
Wang Zhishe, Yang Fengbao, Chen Lei, Peng Zhihao, and Ji Li′e
To overcome the disadvantages of low contrast and missing target information for the existing synthetic aperture radar (SAR) and visible image fusion methods, an image enhanced fusion algorithm based on texture segmentation and top-hat transformation is proposed. Entropy texture image which is generated by gray level cTo overcome the disadvantages of low contrast and missing target information for the existing synthetic aperture radar (SAR) and visible image fusion methods, an image enhanced fusion algorithm based on texture segmentation and top-hat transformation is proposed. Entropy texture image which is generated by gray level co-occurrence matrix of SAR image is segmented by threshold, and the region of (ROI) interest of SAR is extracted. The SAR and optical images are decomposed by the non-subsampled contourlet transform (NSCT). A region fusion rule is introduced to the low-frequency coefficient, and low-frequency coefficient of SAR is chosen in the region of interest. The significant bright and dark image detail features are extracted by top-hat transformation and the low-frequency synthetic coefficient is obtained through adding the above bright and dark features into low-frequency coefficient. High-frequency subband coefficients are fused by selecting maximum significant factor of local directional entropy. The fused image is obtained by the NSCT inverse transformation of the fused coefficient. The experiment results testify the validity of the proposed image fusion algorithm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1010002 (2014)
Imaging Systems
Study on Selection of CCD Detector of Space-Borne Hyper-Spectral Imager
Ma Jun, Xiao Xizhong, Lang Junwei, and Wang Yueming
Signal-to-noise ratio (SNR) and stability of focal plane are important performance index for airborne hyperspectral imaging systems in visible near infrared (VNIR) band. To fulfill the requirement, the rational selection of charge coupled device (CCD) detectors turns to be a key issue. A rapid method is proposed for chSignal-to-noise ratio (SNR) and stability of focal plane are important performance index for airborne hyperspectral imaging systems in visible near infrared (VNIR) band. To fulfill the requirement, the rational selection of charge coupled device (CCD) detectors turns to be a key issue. A rapid method is proposed for choosing compatible CCD based on the scale, pixel size and frame rates of CCD. According to SNR formula of hyperspectral imager in VNIR band, a SNR model and a focal depth model are built. With analysis of a real project application, the selection process is proposed and the calculation when choosing the pixel size (or SNR) of the CCD is particularly elaborated. SNR and focal depth analysis of the selected one is also presented, proving that the models and the method of choosing CCD are rational. Results show that an efficient and accurate means of selecting CCD detectors is proposed for airborne hyperspectral imager..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1011001 (2014)
Image Restoration Based on Degradation Conversion and Seperable Total Variation Model
Wang Bin, Hu Liaolin, and Xue Ruiyang
Image restoration is actually complicated because of the spatial-domain overlapping of noise and blur which can cause image degradation. In order to simplify restoration and improve recovery quality, it is proposed that the original double degradation model being translated into a single degradation model which containImage restoration is actually complicated because of the spatial-domain overlapping of noise and blur which can cause image degradation. In order to simplify restoration and improve recovery quality, it is proposed that the original double degradation model being translated into a single degradation model which contains only dynamic noise by utilizing proximal operator. Based on traditional total variation model, the seperable version is proposed by introducing low-dimension differential projection. The dynamic noise can be removed through first-order gradient descent algorithm. The results show that this method is applicable to a variety of degradation models, which effectively remove noise and blur with edges and details kept, even in a strong degradation environment. This makes degraded image recover to ideal status..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1011002 (2014)
A Study on the Influence of the Axial Distance Error to the Image Quality of the Ptychographic Iterative Engine
Zheng Chen, He Xiaoliang, Liu Cheng, Wang Yueke, Wang Jicheng, and Zhu Jianqiang
Based on the analysis of the axial distance error in the extended ptychographic iterative engine (ePIE), it is pointed out that the influence of the axial distance error to the image quality is equivalent to that of the transverse scanning error. By using the position corrected ePIE algorithm, the image quality degradaBased on the analysis of the axial distance error in the extended ptychographic iterative engine (ePIE), it is pointed out that the influence of the axial distance error to the image quality is equivalent to that of the transverse scanning error. By using the position corrected ePIE algorithm, the image quality degradation induced by the axial distance error can be automatically corrected step by step in the iterative reconstruction..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1011003 (2014)
Inhibiting Intraocular Stray Light Method to Improve Quality of Retinal Image
Xie Hongsheng, Yang Lebao, Xia Mingliang, Li Dayu, and Xuan Li
Using the liquid crystal spatial light modulator and Shack-Hartmann wave front sensor as the core components, an adaptive optics (AO) system for retinal imaging in vivo is constructed. Based on the modulation transfer function, quantitative analysis of the effects of the intraocular stray light on retinal imaging is caUsing the liquid crystal spatial light modulator and Shack-Hartmann wave front sensor as the core components, an adaptive optics (AO) system for retinal imaging in vivo is constructed. Based on the modulation transfer function, quantitative analysis of the effects of the intraocular stray light on retinal imaging is carried out. The result demonstrates that the ocular stray light degrades the quality of the retinal images. According to the change characteristic of the polarization state of intraocular stray light. The fundus is illuminated by the polarized light. With the help of trial lens and sighting target with focal length of 1 m, the light source can be precisely focused on the capillary layer of the retina. Adopting the above mentioned methods, the effect of the ocular stray light is inhibited and the quality of retinal images is improved. Four volunteers participates in the experiments. The clear capillary images are obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1011004 (2014)
Snapshot Compressive Imaging by Phase Modulation
Wu Jianrong, Shen Xia, Yu Hong, Chen Zhe, Liu Zhentao, Tan Shiyu, and Han Shensheng
With the increasing need for higher image resolution and amount of data for imaging, it is imperative to develop novel compressive imaging technology with higher information acquiring efficiency. The rise of compressive sensing theory paves the way for compressive imaging. A snapshot compressive imaging strategy by spaWith the increasing need for higher image resolution and amount of data for imaging, it is imperative to develop novel compressive imaging technology with higher information acquiring efficiency. The rise of compressive sensing theory paves the way for compressive imaging. A snapshot compressive imaging strategy by spatial phase modulation is proposed. The feasibility for the imaging strategy is testified by compressive imaging experiment. The spatial resolution and signal noise ratio are analyzed by theory and testified by the experiments, the restrictive relation between them is released..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1011005 (2014)
Depth of Field Simulation Display for Multi-Focus Images Based on Phased Gaussian Kernel
Xiao Jinsheng, Du Kanghua, Tu Chaoping, 1Lei Junfeng, and Qian Chao
The visual beauty bokeh effect cannot be taken by non single-lens reflex camera, therefore a simulation algorithm for depth of field is presented based on multi-focus image depth information extraction. The mathematical model of heat diffusion equation is built for the multi-focus images. The adaptive depth values of iThe visual beauty bokeh effect cannot be taken by non single-lens reflex camera, therefore a simulation algorithm for depth of field is presented based on multi-focus image depth information extraction. The mathematical model of heat diffusion equation is built for the multi-focus images. The adaptive depth values of initial image are proposed to optimize the solution of partial differential equation. The foreground and background are acquired by splitting the adjusted depth image obtained through regularization. Also, a simulation algorithm for depth of field based on phased Gaussian kernel is proposed to simulate the blur effect in the background caused by a wide aperture camera. Compared with other published algorithms, the results show that this algorithm can not only extract the depth information of the image accurately but also simulate the real depth of field effect..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1011006 (2014)
Instrumentation, Measurement and Metrology
Research on Performance of Random Bitstream Ranging System Based on Single Photon Detection Theory
Shen Shanshan, Chen Qian, He Weiji, Chen Yunfei, Yin Wenye, and Dai Huidong
Pseudo-random bitstream ranging model is researched and a new output signal to noise ratio (SNR) model based on photon statistics model is proposed. The relationship between SNR and code pattern of pseudo-random bitstream with different dead time is studied by Monte-Carlo simulation. The theory model is almost consistePseudo-random bitstream ranging model is researched and a new output signal to noise ratio (SNR) model based on photon statistics model is proposed. The relationship between SNR and code pattern of pseudo-random bitstream with different dead time is studied by Monte-Carlo simulation. The theory model is almost consistent with Monte-Carlo simulation. The results show that with the fraction of randomly distributed 1-bits in transmitted pattern increased, the system SNR is getting better firstly and then getting worse. Best pattern of transmitted bitstream according to different dead time may lead to the best SNR. According to new output SNR model, lower dead time brings better SNR. The system SNR increases firstly then gets down with the growing signal photon counting. Gaussian distribution timing jitter is introduced to reconstruct received bitstream pattern formed from the arrival times of returning single photon. It is found that higher rate of bitstream brings higher possibility error of single time value. Suitable bits rate is restricted to 1 GHz to reduce the probability of ranging error..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1012001 (2014)
Study on Polarization Pattern of Full Moonlight in Clear Sky
Cui Yan, Chen Xiaolong, Chu Jinkui, Chen Chen, Li Chenmu, and Guan Le
The polarization pattern of full moonlight in clear sky is investrgated in order to understand the distribution law of polarization properties of full-sky scattered light better. Night skylight sources have been investigated. The polarization pattern of full moonlight has been simulated based on Rayleigh scattering theThe polarization pattern of full moonlight in clear sky is investrgated in order to understand the distribution law of polarization properties of full-sky scattered light better. Night skylight sources have been investigated. The polarization pattern of full moonlight has been simulated based on Rayleigh scattering theory. The distribution patterns of full moonlight, twilight and sunlight as well as the distribution patterns of continuous observation from twilight to moonlight have been acquired using a full-sky imaging measurement system. After contrasting and analyzing the neutral point and the orientation of meridian line, it is proved that the polarization pattern of full moonlight in clear sky is basically consistent with the simulation results, and it conforms to the Rayleigh scattering theory; the twilight polarization pattern is affected by sunlight and moonlight simultaneously; when the altitude angle of the sun is similar to that of the moon, the distribution trends of polarization patterns are identical; the power of the light does not change the value of skylight polarization distribution patterns..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1012002 (2014)
Research on Angle Measure Error Based on Method of Angle Difference
Chen Haiping, Li Jiabin, Liu Changchun, Xiong Zhao, Zhou Hai, Yuan Xiaodong, and Zheng Wanguo
According to device of angle difference measurement, analyze how the error of angle measurement affect the topography measurement, while using relatively goniometry to measure the direction of sampling′s normal. Using Matlab software to set up the error transmission model, then analyze the regulation of how stability oAccording to device of angle difference measurement, analyze how the error of angle measurement affect the topography measurement, while using relatively goniometry to measure the direction of sampling′s normal. Using Matlab software to set up the error transmission model, then analyze the regulation of how stability of angle measurement influence the topography measurement. The experimental result demonstrates this analysis method is reliable..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1012003 (2014)
Lasers and Laser Optics
Acquisition of Laser Beam Characteristics by Extended Nijboer-Zernike Method
Liu Minshi, Wang Xiaoman, Wang Bin, and Jiang Yupeng
The inverse operation of the extended Nijboer-Zernike (NZ) method is applied to acquire the laser beam characteristics. Two images at the locations before and behind the focal plane are used to calculate the amplitude and phase of wavefront at pupil plane of laser beam. The laser beam quality factor M2, the beam width,The inverse operation of the extended Nijboer-Zernike (NZ) method is applied to acquire the laser beam characteristics. Two images at the locations before and behind the focal plane are used to calculate the amplitude and phase of wavefront at pupil plane of laser beam. The laser beam quality factor M2, the beam width, the divergence, and the Rayleigh range are obtained. The experimental system is established which meets the accuracy requirement. Two actual tests of a He-Ne laser are carried out in different days. The test result of wavefront is compared with that of the phase diversity method and the test results of beam characteristics are compared with that of M2-200s-FW beam analyzer, which shows that the proposed method is reasonable. The stability and reliability of the established system is verified by comparison of the tests in different days..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1014001 (2014)
Diode-Pumped Single-Pass Mid-Infrared Fiber Gas Laser
Wang Zefeng, and Yu Fei
A diode-pumped single-path mid-IR fiber gas laser is reported. 3.1~3.2 μm laser emission is generated in a 2.3 m low-loss negative curvature hollow core photonic crystal fiber (HC-PCF) filled with low pressure acetylene, pumped by a modulated, amplified, tunable 1.5 μm diode laser. The maximum energy conversion efficieA diode-pumped single-path mid-IR fiber gas laser is reported. 3.1~3.2 μm laser emission is generated in a 2.3 m low-loss negative curvature hollow core photonic crystal fiber (HC-PCF) filled with low pressure acetylene, pumped by a modulated, amplified, tunable 1.5 μm diode laser. The maximum energy conversion efficiency is higher than 14.5% at 200 Pa, and the minimum laser threshold is lower than 100 nJ at 100 Pa. This research potentially provides an effective rout to obtain compact, high-power mid-IR fiber gas laser..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1014002 (2014)
Orange Laser at 604 nm and Multi-Wavelength Emissions of Orange and Red Laser of Pr3+:LiYF4 Pumped by Blue LD
Yang Han, Xu Bin, Cai Zhiping, Zhong Yile, Cheng Yongjie, Qu Biao, and Xu Huiying
A maximum output power of 166.6 mW at 607.4 nm (σ polarization) is achieved in bulk PrYLF laser crystal pumped by blue laser diode (LD). An operation of 604.6 nm (π polarization) laser with maximum output power of 60.6 mW and slope efficiency of 13.6% is got by inserting a 0.1 mm glass plate into the laser cavity as frA maximum output power of 166.6 mW at 607.4 nm (σ polarization) is achieved in bulk PrYLF laser crystal pumped by blue laser diode (LD). An operation of 604.6 nm (π polarization) laser with maximum output power of 60.6 mW and slope efficiency of 13.6% is got by inserting a 0.1 mm glass plate into the laser cavity as frequency selector. Simultaneous multi-wavelength emissions at 607, 604, and 640 nm are also obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1014003 (2014)
Machine Vision
Nonmetric Lens Distortion Calibration Based on Collinear Vectors
Zhou Ziqing, Zhao Peng, Li Bo, and Chen Qimei
Lens distortion is coupled with intrinsic and extrinsic camera parameters in traditional camera calibration algorithms. An algorithm which separates lens distortion from camera parameters is proposed. The algorithm is based on the fundamental property that a camera follows the perspective camera model if and only if thLens distortion is coupled with intrinsic and extrinsic camera parameters in traditional camera calibration algorithms. An algorithm which separates lens distortion from camera parameters is proposed. The algorithm is based on the fundamental property that a camera follows the perspective camera model if and only if the projection of every three dimensional (3D) line in space onto the camera plane is a line. For undistorted images, the cross product of collinear vectors which consist of any two feature points on a line should be a zero vector. Distortion parameters are found by using nonlinear optimization algorithms and the coupling between distortion center and distortion coefficient is also discussed. An evaluation method for the effect of distortion correction is designed so as to prove the correctness of the proposed algorithm. Once distortion correction is completed, intrinsic and extrinsic camera parameters can be solved linearly. The experimental results indicate that the proposed algorithm can implement the solving of all camera parameters by using only one calibration image. As a result, the efficiency of calibrating is improved. Moreover, the proposed algorithm performs more stably and has nearly the same accuracy as traditional methods..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1015001 (2014)
Vanishing Point Detection Algorithm for Urban Road Image Based on the Envelope of Perpendicular and Parallel Lines
Ding Weili, Li Yong, Wang Wenfeng, and Zou Yuanyuan
Identifing the road vanishing point from a single image is one of the key technologies in unmanned, intelligent navigation and other areas. A new vanishing point detection algorithm based on the envelope of perpendicular and parallel lines is proposed for typical urban road and street images. All parallel line pairs inIdentifing the road vanishing point from a single image is one of the key technologies in unmanned, intelligent navigation and other areas. A new vanishing point detection algorithm based on the envelope of perpendicular and parallel lines is proposed for typical urban road and street images. All parallel line pairs in a single image are extracted, vertical lines present in the image are used to propose on envelope estimation method to segment the road area and extract the parallel line pairs in the road area effectively. Grouping in different directions is used to divide the road parallel lines into two categories, and the intersections of the approximately symmetrical lines are solved. By using the C-means clustering and statistical method, the vanishing point in the city road scene is estimated. The experimental results show that the proposed algorithm can estimate the vanishing point in the urban road scene accurately and effectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1015002 (2014)
Binocular Vision Method of Measuring Pose Based on Perpendicular Lines
Zhao Zhenqing, Ye Dong, Chen Gang, and Guo Yubo
For linear features, an algorithm which is based on perpendicular lines is proposed for binocular vision pose measurement. The algorithm is based on linear feature and its projection line on the camera image coplanar property. Unit quaternions is used to simplify model variables. Under the condition of two known perpenFor linear features, an algorithm which is based on perpendicular lines is proposed for binocular vision pose measurement. The algorithm is based on linear feature and its projection line on the camera image coplanar property. Unit quaternions is used to simplify model variables. Under the condition of two known perpendicular on object, an analytical solution of object pose can be determined with four lines which is projected by two perpendicular lines on two-camera image. The algorithm is also analyzed when linear vector projected onto the two cameras on the same line, namely linear vector parallel to the two camera position. Matlab simulation results show that the algorithm is robust to noise and can guarantee a certain precision even if the two straight lines have error for vertical. Physical experiments show that the algorithm can meet the general precision requirements..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1015003 (2014)
A Fully Automatic Camera Calibration Method Based on Planar Target
Bu Penghui, Zhao Hong, Gu Feifei, Ma Yueyang, and Li Huanhuan
How to calibrate cameras rapidly and precisely is always a pressing problem in the visual measurement. Now there are many calibration mehods for different camer imaging models. A sorting algorithm for chess-board nodes based on the round marker, polar radius and polar angle is proposed, so that realize fully automatic How to calibrate cameras rapidly and precisely is always a pressing problem in the visual measurement. Now there are many calibration mehods for different camer imaging models. A sorting algorithm for chess-board nodes based on the round marker, polar radius and polar angle is proposed, so that realize fully automatic calibration for single and binocular camera high-precision automatic calibration. Experiments vevify the effective and robust of the algorithm for different pose calibration images. Results show that the improved calibration ensures the calibration accuracy of the camera and improves the level of automation calibration, so it can be widely used in the calibration of single and binocular camera..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1015004 (2014)
Calibrating Laser Scanning Probe with Double Virtual Circle Target
Lu Minxun, Ge Weiliang, Zhou Aiguo, Lü Gang, and Zhou Fei
A new calibration method for laser plane with double virtual circles is put forward. This method creates double virtual circles in the image coordinate using the corners of chessboard. Position relationship is established between the virtual circles and the laser stripes. The feature point coordinates of the laser striA new calibration method for laser plane with double virtual circles is put forward. This method creates double virtual circles in the image coordinate using the corners of chessboard. Position relationship is established between the virtual circles and the laser stripes. The feature point coordinates of the laser stripe in the camera coordinate system are calculated according to the principle of cross-ratio invariance. The chessboard position is changed for several times within the field of the camera vision aiming to calculate more feature points. All these feature points are fitted to an ideal plane by the least square method (LSM). The experimental results indicate that the precision is obviously higher than the actual circle target. The root mean square (RMS) error of the laser plane calibration is 0.04 mm and the target is easier to make. It concludes that the calibration process is simple, reliable and suits for calibration on spot..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1015005 (2014)
Human Action Recognition Based on Local Image Contour and Random Forest
Cai Jiaxin, Feng Guocan, Tang Xin, and Luo Zhihong
Human action recognition in videos has attracted more and more attentions. In view of the local expression of human behavior, a novel local contour feature representing body posture is proposed, which can make full use of information of the contour variation along both horizontal and vertical direction. The proposed loHuman action recognition in videos has attracted more and more attentions. In view of the local expression of human behavior, a novel local contour feature representing body posture is proposed, which can make full use of information of the contour variation along both horizontal and vertical direction. The proposed local feature can distinguish different actions and is invariant to translation, scaling, rotation and change of start point of human contour. A two stage classifying framework based on random forest is also proposed by using this novel local body contour feature. Random forest is employed to classify each frame of the test video. After that, a video classification method based on out of bag(OOB) error weighted voting strategy to recognize action video according to the ratio of decision trees belonging to each local contour to total decision trees is proposed. Experimental results on test data set prove the effectiveness of proposed method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1015006 (2014)
Materials
Third-Order Nonlinearity of Sb Quantum Dots Doped Na2O-B2O3-SiO2 Glass
Ma Xin, Xiang Weidong, Zhong Jiasong, Zhang Chenglong, Pei Lang, and Liang Xiaojuan
Antimony (Sb) quantum dots doped in sodium borosilicate glass are synthesized through sol-gel method using tetraethyl orthosilicate(TEOS), boracic acid, and metallic sodium as precursors. Ultraviolet-visible (UV-vis) absorption spectrometer shows that the surface plasma resonance absorption peak of the quantum dots glaAntimony (Sb) quantum dots doped in sodium borosilicate glass are synthesized through sol-gel method using tetraethyl orthosilicate(TEOS), boracic acid, and metallic sodium as precursors. Ultraviolet-visible (UV-vis) absorption spectrometer shows that the surface plasma resonance absorption peak of the quantum dots glass is about 566 nm. Nonlinear optical properties of Sb quantum dots doped glass are investigated by using Z-scan technique at the wavelength of 800 nm with femtosecond Tisapphire laser radiation. The values of nonlinear refraction index γ, nonlinear absorption coefficient β and the third-order nonlinear optical susceptibility χ(3) of the glass are estimated to be 8.59×10-17 m2/W, 1.80×10-10 m/W, 4.75×10-11 esu, respectively. X-ray powder diffraction (XRD) analyses reveal that Sb quantum dots with rhombic hexahedron phase are successfully doped in glass substrate. The size and distribution of the quantum dots are measured by transmission electron microscopy (TEM) as well as high-resolution transmission electron microscopy (HRTEM), the results show that spherical shape have formed uniformly in the glass, and the size of these quantum dots rang from 19 to 25 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1016001 (2014)
A Study on Microscopic Mechanism and Optical Gas Sensing Material Characteristics of Rutile Titanium Dioxide (110) Surface Adsorption NH3 Molecules
Zhu Hongqiang, and Feng Qing
The study on characteristics of optical gas sensing materials after gas adsorption is a hot issue. The microscopic mechanism and optical characteristics of rutile titanium dioxide (110) surface adsorption NH3 molecules are studied. The results show that NH3 molecules are easy to be adsorbed by rutile titanium dioxide (The study on characteristics of optical gas sensing materials after gas adsorption is a hot issue. The microscopic mechanism and optical characteristics of rutile titanium dioxide (110) surface adsorption NH3 molecules are studied. The results show that NH3 molecules are easy to be adsorbed by rutile titanium dioxide (110) surface containing oxygen vacancies. The higher of oxygen vacancy concentration, the more stability of NH3 adsorption, and the main way of surface adsorption NH3 molecule is negative charge center down. When oxygen vacancy concentration reached 33%, adsorption energy is 1.7313 eV. The adsorption of NH3 is chemical adsorption, and the H atom of NH3 is reduced and N atom is oxidized. In visible light range from 1.5 eV to 3.1 eV, the higher concentration of oxygen vacancy, the more obvious improvement of absorption, reflection ability and optical gas sensing performance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1016002 (2014)
Optical Design and Fabrication
Thermal Noise Analysis and Correction of Infrared Conformal Dome
[in Chinese], [in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
When the optical dome of aerobat is initially subjected to aerodynamic flight conditions, the temperature of front surface rises rapidly. The thermal optical dome produces a sharp increase in background radiance on the focal plane detector, which can mask the target signal and decrease the ability of target tracking. IWhen the optical dome of aerobat is initially subjected to aerodynamic flight conditions, the temperature of front surface rises rapidly. The thermal optical dome produces a sharp increase in background radiance on the focal plane detector, which can mask the target signal and decrease the ability of target tracking. Infrared conformal dome has demonstrated its capabilities as a prominent technique for supersonic aero thermal radiation effect. Aero thermal radiation effect of conformal infrared dome is described. The thermal noises of conformal dome are measured by infrared blackbody when dome temperature decreases from 460 K to 320 K. Quadratic surface as noise correction model decided by dualistic nolinear regression analysis is introduced, and the coefficient of determination of quadratic surface fitting is 0.8683. The mean signal noise ratio of the image is increased to 13.7 dB after noise correction by noise correction model. The signal noise ratio of infrared image increases 6.5 dB after noise correction. The result can meet the precision requirement of target tracking system and provide partial evidence for optics system optimization..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1022001 (2014)
Broad Dual-Band Kinoform Infrared Double-Layer Diffractive Optical System Desgin
Mao Wenfeng, Zhang Xin, Qu Hemeng, Zhang Jizhen, and Wang Lingjie
A dual-band infrared optical system working in both mid-wave infrared (MWIR) (3~5 μm) and long-wave infrared (LWIR) (8~14 μm) has been designed with the double-layer Kinoform diffractive optical elements (DOEs). The system is comprised of four lenses , two ZnS lenses and two ZnSe lenses, and its focal length is 100 mm A dual-band infrared optical system working in both mid-wave infrared (MWIR) (3~5 μm) and long-wave infrared (LWIR) (8~14 μm) has been designed with the double-layer Kinoform diffractive optical elements (DOEs). The system is comprised of four lenses , two ZnS lenses and two ZnSe lenses, and its focal length is 100 mm with F number of 1.2. The average efficiency of double-layer DOEs made of ZnS and ZnSe is more than 96%. The aberration of the system has been improved perfectly. When the Nyquist frequency is less than 14.3 lp/mm, the modulation transfer function (MTF) in MWIR is more than 0.7, which approaches to the diffraction limit. The MTF in LWIR is more than 0.65 in the same frequency. The effect of the efficiency for the MTF has been analysed. Due to the high diffraction efficiency, efficiency is not the main effect element for the performance of the system. A figure generated by the Matlab software shows the curves of the profile of DOEs. The blazed depths of the two kinoform surface have been calculated by the same software, which is 179.3 μm amd 159.4 μm, respectivly. The minimum feature size of the DOEs is 1.41 mm. It can be manufactured by the single-point diamond tuning (SPDT) technology easily and precisely..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1022002 (2014)
Study of Large-Diameter Laser Emission Window Stitching Program
Liu Xutang, and Gao Yunguo
Since multi-band high-energy laser emission window′s diameter is large, single ZnSe lens can′t satisfy the working requirements. A window splicing method is proposed. According to the equipment′s actual stress, the window′s strength is calculated to make the window′s design more reasonable and reliable. The window′s boSince multi-band high-energy laser emission window′s diameter is large, single ZnSe lens can′t satisfy the working requirements. A window splicing method is proposed. According to the equipment′s actual stress, the window′s strength is calculated to make the window′s design more reasonable and reliable. The window′s boundary conditions is acquired through analysis of the equipment′s work environment and further detailed analysis by using finite element software is done to study laser emission window′s mirror deformation under the effect of thermal coupling force. Then, fitting of inner and outer surface of the window by Zernike polynomials is carried out to obtain the Zernike expressions of the window′s surface shape. The window′s influence on the beam while working in complex environment is analyzed from the view of beam divergence, times of diffraction limitation β and fractional encircled energy RBQ by Matlab. The results show that stitching can greatly reduce the cost and quality of the window and the impact of laser beam is fare, it can meet the equipment requirement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1022003 (2014)
Source Optimization Method of Lithography Tools Based on Quadratic Programming
Yan Guanyong, Li Sikun, and Wang Xiangzhao
In this paper, we propose a source optimization method of lithography tools based on quadratic programming. The fidelity of the aerial image to the mask object pattern is designed as the object function. Then by using the linear relationship between the aerial image and point sources, the source optimization is transfoIn this paper, we propose a source optimization method of lithography tools based on quadratic programming. The fidelity of the aerial image to the mask object pattern is designed as the object function. Then by using the linear relationship between the aerial image and point sources, the source optimization is transformed to a quadratic programming problem. The mask object pattern is divided into a limitation area and a comparison area. The constraint condition is applied in the limitation area and the object function is applied in the comparison area. The one-dimensional (1D) isolated space and two-dimensional (2D) contact hole array patterns are used to validate our method. The impacts of the threshold and focus on the optimization results are studied. According to the simulation results, the global optimization source is obtained by using the proposed method. The image quality is improved and the process window is increased after the source optimization..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1022004 (2014)
Optical Devices
Four-Port Cross-Shaped Circulator Based on Two-Dimensional Magneto-Photonic Crystals
Wang Yong, Zhang Dengguo, Ouyang Zhengbiao, and Li Jingzhen
A new defect structure of two-dimensional magnetic-photonic crystal with dielectric cylinders is given and a four-port cross-shaped circulator using five ferrite posts is envisaged. Based on the agreements between the resonance frequency of micro-cavity constructed by a point defect in the two-dimensional (2D) square lA new defect structure of two-dimensional magnetic-photonic crystal with dielectric cylinders is given and a four-port cross-shaped circulator using five ferrite posts is envisaged. Based on the agreements between the resonance frequency of micro-cavity constructed by a point defect in the two-dimensional (2D) square lattice photonic crystal with those numerical results of related literatures, external characteristics of the circulator are calculated by the plane wave expansion method and finite element method. The results show that at the center frequency, the isolation of circulator is up to 23.49dB and the lowest insertion loss is 0.0281 dB; when frequency diverges from the center frequency, the transmission characteristics of the circulator deteriorate gradually with increasing frequency offset. This design of circulator with only one ferrite cylinder in the waveguides, which solves the high loss from multiple cylinders..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1023001 (2014)
Individually Addressable Color-Tuning White Organic Light-Emitting Diodes
Zhang Chao, Guo Kunping, Lin Yang, Xu Tao, Zhang Jianhua, and Wei Bin
This paper proposes a novel method to control the emission spectrum of the white organic light-emitting devices (WOLEDs) and improve the device efficiency, which uses Al/Ag as an interconnect layer of the stacked WOLEDs. When the interconnection layer decreases to 5 nm from 9 nm, the Commission Internationale de I′EclaThis paper proposes a novel method to control the emission spectrum of the white organic light-emitting devices (WOLEDs) and improve the device efficiency, which uses Al/Ag as an interconnect layer of the stacked WOLEDs. When the interconnection layer decreases to 5 nm from 9 nm, the Commission Internationale de I′Eclairage coordinates change to (0.38, 0.31) from (0.27, 0.29) within the white-light region. Moreover, we have successfully achieved the complementary WOLEDs (blue and orange) with the desired color temperature (CT), which varies from 8009 K to 4539 K, demonstrating that the CT can be regulated by individual cells. Finally, the paper discusses the optical-electrical characteristics of CT-controllable RGB WOLEDs based on individually addressable method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1023002 (2014)
OPTOELECTRONICS
High Pass Filter Characteristics of Saturated Quantum Dot Semiconductor Optical Amplifiers
Shen Suqi, Ling Yun, Liao Lidan, He Binbin, Qiu Kun, and Zheng Mian
Quantum dot semiconductor optical amplifiers (QDSOAs) are ideal devices for optical signal processing due to their shorter carrier recovery time and larger amplification bandwidth. With the three-level electron transition rate equations and the traveling-wave equations in QDSOAs, a segmented numerical model of the actiQuantum dot semiconductor optical amplifiers (QDSOAs) are ideal devices for optical signal processing due to their shorter carrier recovery time and larger amplification bandwidth. With the three-level electron transition rate equations and the traveling-wave equations in QDSOAs, a segmented numerical model of the active region is established. Based on this model, the frequency response characteristics of saturated QDSOAs are obtained and the impacts of input optical power, injection current, active region length, maximum modal gain and carrier transition time on the 3 dB cutoff frequency and suppression ratio are investigated. The results show that the saturated QDSOA has a high pass filter characteristic with large bandwidth and a high 3 dB cutoff frequency. By optimizing the QDSOAs′ parameters, the more excellent properties can be obtained than the traditional buck or quantum well semiconductor optical amplifiers. These features will provide useful theoretical instructions on the designs and applications of QDSOAs at the saturated states..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1025001 (2014)
Quantum Optics
Entanglement Enhancement of Bipartite Entangled States Through Coherent Feedback Control
Li Fang, Zhou Yaoyao, and Jia Xiaojun
Einstein-Podolsky-Rosen (EPR) entangled state is an essential resource in quantum information and quantum computation. With the deep development of research, bipartite entangled states of light with high entangled degree should be obtained firstly to complete quantum information processing efficiently. It has been provEinstein-Podolsky-Rosen (EPR) entangled state is an essential resource in quantum information and quantum computation. With the deep development of research, bipartite entangled states of light with high entangled degree should be obtained firstly to complete quantum information processing efficiently. It has been proved an effective method to improve the quality of entangled light field by manipulation of entangled states of light. Coherent feedback control has been proved to enhance the squeezed degree of the squeezed state light field because of bring no additional noise to the optical parametric system. We theoretically calculate the relationship between the quantum correlation noise of the EPR entangled state generated from coherent feedback control non-degenerate optical parametric amplifier and various parameters of the total system, and the influence of these parameters on the entanglement enhancement is also analyzed detailedly. This provides references for further research on the EPR entangled state with higher entangled degree..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1027001 (2014)
Remote Sensing and Sensors
Analyzing of Optical Remote Polarization Imaging Simulation Based on Intensity Images and Surface Polarized Bidirectional Reflectance Data
Huang Honglian, Yi Weining, Qiao Yanli, Du Lili, and Cui Wenyu
For getting the samples of polarization imaging needed by the development of polarization imaging sensors and compensating the lack of experimental data usually in the research of polarization imaging simulation, a method of polarization imaging simulation based on the combination of intensity images and experimentallyFor getting the samples of polarization imaging needed by the development of polarization imaging sensors and compensating the lack of experimental data usually in the research of polarization imaging simulation, a method of polarization imaging simulation based on the combination of intensity images and experimentally measured surface polarized bidirectional reflectance data is proposed. Several of the simulated images under different atmospheric and geometric conditions at the height of satellite are provided to illustrate the realization processing of the method. The comparison with the simulated intensity images in the same circumstance shows that, the contrast of polarization images are less affected by low visibility, the advantage appears more prominent in the conditions of backscatter or some particular directions. The fact that the clarity of polarization imaging is more sensitive to observational direction suggests that the simulation is helpful for the selection of a specific direction for polarization imaging. Eventually, it is helpful for enhancing the ability of identifying the ground target in haze conditions through polarization imaging..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1028001 (2014)
Spectroscopy
Analysis of Wedge Error of Beam Splitter in Spatial Modulation Fourier Transform Infrared Spectrometer
Lü Jinguang, Liang Jingqiu, Liang Zhongzhu, Qin Yuxin, and Tian Chao
Due to the restriction of manufacture precision to beam splitter in spatial modulated Fourier transform infrared spectrometer, the wedge error will be existed on the substrate of beam splitter. Through the analysis of the propagation characteristics of the beam in beam splitter, the deviation of optical path differenceDue to the restriction of manufacture precision to beam splitter in spatial modulated Fourier transform infrared spectrometer, the wedge error will be existed on the substrate of beam splitter. Through the analysis of the propagation characteristics of the beam in beam splitter, the deviation of optical path difference caused by the wedge angle is gained, and then the functional relations between interference irradiance and wedge angle error, recovered spectrum and wedge angle error are obtained. The result shows that the wedge error can induce the spectral line shift to lower frequency and reduce the spectral resolution by means of simulation. After the theoretical analysis, the error tolerance of wedge angle under the wavenumber precision and spectral resolution is gained. Aiming at the interferogram intensity distribution influenced by wedge angle, a method of spectrum correction resolving the linear equation by discrete spectrum sequence is put forward, and the correction effect is proved well..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1030001 (2014)
Multispectral Measurements of Infrared Spectral Characteristics of an Aircraft
Xiao Xizhong, Wang Yueming, Ma Jun, and Wang Jianyu
The spectral characteristics of infrared radiation from aircraft body and its plume provide a basis for band selection to detect and track the aircraft. Accurate spectral characteristics improve the performances of detection and tracking. Field multispectral measurements of the characteristics are introduced. A radiatiThe spectral characteristics of infrared radiation from aircraft body and its plume provide a basis for band selection to detect and track the aircraft. Accurate spectral characteristics improve the performances of detection and tracking. Field multispectral measurements of the characteristics are introduced. A radiation transfer model which helps to measure the aircraft plume is proposed and analyzed. Furthermore, a multispectral imager with spectroscopic filters is designed. It uses a mid-infrared detector, of which the dimension is 640 pixel×512 pixel, and the spectral response covers 3.7~4.8 μm. The noise performance of the imager is also evaluated. A civil aeroplane is selected for the measurements. Under the transfer model, the radiances of the aircraft, both the body and the plume, are obtained in 4 spectral bands. Compared to the conventional method, more accurate infrared spectral characteristics of aircraft are acquired..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1030002 (2014)
Comparative Study on Performances of Long-Wave Infrared Imaging Spectrometers Based on Offner Form and Dyson Form
Sun Jiayin, Liu Ying, Li Chun, Liu Jianzhuo, Zhang Xiaolong, and Sun Qiang
In view of the difficulties in traditional long-wave infrared imaging spectrometer which is hard to realize a high signal-to-noise ratio and miniaturization as well under the weak remote sensing signal, two types of concentric optical systems, Offner convex grating and Dyson concave grating imaging spectrometers, are dIn view of the difficulties in traditional long-wave infrared imaging spectrometer which is hard to realize a high signal-to-noise ratio and miniaturization as well under the weak remote sensing signal, two types of concentric optical systems, Offner convex grating and Dyson concave grating imaging spectrometers, are designed and analyzed under the common numerical apertures (NA) of 0.19 and 0.33 with spectral range of 8~12 μm. The optimal structures are achieved by optical design software Zemax. The two structures both have a perfect image at NA1=0.19, the size of Offner structure is 245 mm×213 mm×111 mm, value of modulation transfer function (MTF) is higher than 0.38, spectral resolution is 35 nm, smile is lower than 4.8% and keystone is lower than 12.8%. The size of Dyson structure is 308 mm×61 mm×49 mm, value of MTF is higher than 0.48, spectral resolution is 12 nm, smile is lower than 0.047% and keystone is lower than 0.138%. Dyson has an ideal image at NA2=0.33 different from Offner. The size of Dyson structure is 317 mm×88 mm×88 mm, value of MTF is higher than 0.71, spectral resolution is 1 nm, smile is lower than 0.015% and keystone is lower than 0.028%. It is obvious that Dyson structure possesses advantages of larger numerical aperture, smaller volume, higher spectral resolution, higher MTF, lower smile and lower keystone in long-wave infrared wavelengths compared with Offner structure..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1030003 (2014)
Thin Films
Electrochromic Properties of Ta Doped Tungsten Oxide Thin Films
Sun Xilian, Fang Yanqun, and Cao Hongtao
In order to improve the electrochemical cycling stability of electrochromic tungsten oxide (WO3) thin films, Ta-doping WO3 films are prepared by magnetron sputtering method. Microstructure, optical and electrochromic properties of the films are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM)In order to improve the electrochemical cycling stability of electrochromic tungsten oxide (WO3) thin films, Ta-doping WO3 films are prepared by magnetron sputtering method. Microstructure, optical and electrochromic properties of the films are investigated by X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), spectra ellipsmetry (SE), ultraviolet-visible spectrophotometer and cyclic voltammetry, respectively. The influence of Ta-doping on the structure of WO3 thin film and electro-chromism is studied. The results indicate that incorporation of proper content of Ta in WO3 can control the microstructure of the film, which decreases the crack and makes the film smooth. However, excessive Ta can make film dense, or even form agglomerates, which can adversely affect ion transport in the films. Compared to pure WO3 film, the optical modulation, color efficiency and cyclic stability of the Ta-doping WO3 film are improved..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1031001 (2014)
Properties of Iridium Thin Films Fabricated by Atomic Layer Deposition
Ye Zhijie, Shen Weidong, Zhang Yueguang, Zhang Xing, Yuan Wenjia, Li Yanghui, and Liu Xu
Ir(acac)3 and O2 are used as chemical precursors to deposit iridium thin films on Si and quartz substrates by atomic layer deposition(ALD) at the temperature of 340 ℃. Characteristics of the films such as optical properties, microstructure and surface morphological image are investigated by reflectance spectrometer, X-Ir(acac)3 and O2 are used as chemical precursors to deposit iridium thin films on Si and quartz substrates by atomic layer deposition(ALD) at the temperature of 340 ℃. Characteristics of the films such as optical properties, microstructure and surface morphological image are investigated by reflectance spectrometer, X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS), scanning electron microscope(SEM) and atomic force microscopy (AFM). The results show that the films have polycrystalline morphology of nanoparticles and smooth surfaces, low impurity content. The thin films exhibits good optical properties in the ultraviolet spectral region, and it can be well used for Ir grating and other optical devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1031002 (2014)
Application of Spectroscopic Ellipsometry for the Study of Electrical and Optical Properties of Indium Tin Oxide Thin Films
Hu Hui, Zhang Liping, Meng Fanying, and Liu Zhengxin
The dielectric function transformation of ITO thin films caused by different substrates and post annealing temperatures is studied by spectroscopic ellipsometry measurement using Drude and Tauc-Lorentz combined modes. By comparing with the Hall effect measurement results and optical bandgap values calculated from transThe dielectric function transformation of ITO thin films caused by different substrates and post annealing temperatures is studied by spectroscopic ellipsometry measurement using Drude and Tauc-Lorentz combined modes. By comparing with the Hall effect measurement results and optical bandgap values calculated from transmittance and reflectance spectra, it is found that the influences on the dielectric functions from the carrier concentration and optical bandgap values occur at infrared and ultraviolet wavelength regions, respectively. The relationship between the dielectric functions and carrier concentration and optical bandgap is deducted by studying the dielectric functions at low and high energy regions. This study provides a new technological way to analysis the electrical and optical properties of ITO thin films by non-contact spectroscopic ellipsometry measurements..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1031003 (2014)
Vision, Color, and Visual Optics
Research on Image Reconstruction of Traditional Chinese Painting Art Based on Radiance Information Matching
Qin Feng, Yang Weiping, Yang Jia, Li Hongning, Luo Yanlin, Lü Xiankui, Liu Yichao, and Zou Jiping
Reflection parameters and characteristics of traditional Chinese painting samples are measured and analyzed. A method used to reconstruct traditional Chinese painting image based on radiance information matching is put forward to combine with the colorimetry theory. Hue saturation intensity (HSI) color space is used toReflection parameters and characteristics of traditional Chinese painting samples are measured and analyzed. A method used to reconstruct traditional Chinese painting image based on radiance information matching is put forward to combine with the colorimetry theory. Hue saturation intensity (HSI) color space is used to separate traditional Chinese painting information of luminance and chroma, and the radiance values which are measured by PR-715 under different illuminating angles are fitted depending on Gaussian function. Thereby the relationship of spatial function between radiance and illuminating angles is built. Images which are shot under 90° illuminating angle are chosen to be the referential color pieces. The images of traditional Chinese painting color pieces can be reconstructed by combining the information of radiance in imaging HSI color space and functional expression of spatial fitting radiance. The results are compared with the real pictures which are shot by Canon EOS 400D single lens reflex camera. Results indicate that images of traditional Chinese painting color pieces can be reconstructed accurately depending on radiance information matching. This method has high feasibility and reliability, as well as important practical application value for reconstruction and reproduction of the digital cultural heritage for painting art..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1033001 (2014)
X-Ray Optics
Multi-Spectrum Computed Tomography Imaging Method Based on Energy Spectrum Filtering Separation
Niu Suyun, Pan Jinxiao, and Chen Ping
With the development of technology, the traditional single-energy X-ray computed tomography (CT) imaging technology can′t meet the modern industry needs of functional imaging for substance distinction and identification because of the inconsistency between the projection acquisition process and the reconstruction assumWith the development of technology, the traditional single-energy X-ray computed tomography (CT) imaging technology can′t meet the modern industry needs of functional imaging for substance distinction and identification because of the inconsistency between the projection acquisition process and the reconstruction assumption. A multi-spectrum CT imaging method based on energy spectrum filtering separation in view of photon counting imaging detector is presented. Spectrum filtering separation is realized by filtering at X-ray source and monochromatic projection sequence is gotten by various energy imaging. Then an EM-TV algorithm is used at the condition of low dose. By this method, mult-spectrum imaging is realized to meet the demand of substance distinction. Simulation result, which aims at components whose densities are similar, shows that this way can meet the requirement of component discrimination..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1034001 (2014)
Characteristic Study and Application of the Soft X-Ray Beam Line 4B7B on BSRF
Yi Rongqing, Zhao Yidong, Wang Qiuping, Zheng Lei, Yang Jiamin, He Xiaoan, Li Chaoguang, Jiang Shaoen, Ding Yongkun, and Cui Mingqi
This subject improves light source capability of the soft X-ray beam line 4B7B on the Beijing synchrotron radiation facility (BSRF) by restraining the low energy X-ray in high energy range and the higher-harmonics wave in every energy point. This light source has harmonics wave less than 1%, energy resolution of more tThis subject improves light source capability of the soft X-ray beam line 4B7B on the Beijing synchrotron radiation facility (BSRF) by restraining the low energy X-ray in high energy range and the higher-harmonics wave in every energy point. This light source has harmonics wave less than 1%, energy resolution of more than 3000. Some researches on calibration of X-ray detector (XRD) sensitivity, mirror reflectivity, filter transmittance on the soft X-ray beam line 4B7B are performed. The results show that the uncertainty of XRD sensitivity is less than 3%, the uncertainty of mirror reflectivity is less than 3.5%, and the uncertainty of filter transmittance is less than 1%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 34, Issue 10, 1034002 (2014)
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