Contents
2013
Volume: 33 Issue 3
50 Article(s)
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Atmospheric Optics and Oceanic Optics
Feasibility Study for Acquiring Sa(z) Value of Background Aerosol Using Two-Point Calibration Method
Liu Houtong, Zhao Jianxin, Mo Xutao, and Han Yufeng
Feasibility of using two-point calibration method to acquire aerosol extinction-to-backscattering ratio is explored. Two-point calibration method is one of the important methods for acquiring aerosol extinction-to-backscattering ratio. The relationship between the distance of the two calibration points and the accuracyFeasibility of using two-point calibration method to acquire aerosol extinction-to-backscattering ratio is explored. Two-point calibration method is one of the important methods for acquiring aerosol extinction-to-backscattering ratio. The relationship between the distance of the two calibration points and the accuracy of aerosol extinction-to-backscattering ratio acquired by using two-point calibration method is discussed. The aerosol extinction-to-backscattering ratio obtained by using two-point calibration method is reliable when the distance between the two points is greater than 1 km. The influence of the distance between the two calibration points on the inversion results of aerosol extinction-to-backscattering ratio from one calibration point to another one is analyzed. The influence to aerosol extinction-to-backscattering ratio inversion results of two different iterative methods is discussed. The feasibility of beforehand error estimation of inversion results when two-point calibration method is used for the inversion of aerosol extinction-to-backscattering ratio is investigated. The inversion results show that the error of aerosol extinction-to-backscattering ratio between the two calibration points does not exceed 6% generally when the distance between the two calibration points is greater than 1 km and the extinction coefficient error of the calibration point is 5%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 301001 (2013)
Multi-Channel Adaptive Control Algorithm for Closed-Loop Adaptive Optics System
Yan Zhaojun, Li Xinyang, and Rao Changhui
A multi-channel adaptive control algorithm (MACA) that can be put into practice in the closed-loop adaptive optics (AO) system is proposed. MACA, unlike the traditional control algorithm, considers the effect of atmospheric turbulence and the system time delay together with the dynamic characteristics of AO system. TheA multi-channel adaptive control algorithm (MACA) that can be put into practice in the closed-loop adaptive optics (AO) system is proposed. MACA, unlike the traditional control algorithm, considers the effect of atmospheric turbulence and the system time delay together with the dynamic characteristics of AO system. The control parameters in each control loop can be modified timely during iterative calculation, which can make the system work at the best control state. Taking a 61-element AO system as an example, based on numerical simulation, MACA is studied to control the voltages of deformable mirror in advance. Analyses are made on convergence, control performance and control bandwidth of this algorithm. Compared with the classical proportional integral (PI) control algorithm, simulation results show that the residual error caused by turbulence in the system is reduced more effectively by using MACA which has good adaptability and improves the closed-loop control bandwidth and control properties of AO system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 301002 (2013)
Method of High Accuracy Celestial Altitude Obtainment in Vessel Navigation
Ning Xiaolin, and Wang Longhua
Positioning accuracy of vessel celestial navigation is limited by the low measurement accuracy of celestial altitude. For solving this problem, a novel method of celestial altitude determination is proposed. Refraction angles are obtained by two star sensors using a star pattern recognition method; the celestial altituPositioning accuracy of vessel celestial navigation is limited by the low measurement accuracy of celestial altitude. For solving this problem, a novel method of celestial altitude determination is proposed. Refraction angles are obtained by two star sensors using a star pattern recognition method; the celestial altitudes are calculated accurately from the refraction angles according to the atmospheric refraction model. Simulation results show that the final vessel positioning accuracy can be better than 23 m under the conditions that the star sensor accuracy is 1″ and the observation altitude is about 6°. The effect of measurement accuracy of refraction angle, observation celestial heights and atmospheric refraction model accuracy on positioning accuracy is analyzed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 301003 (2013)
Research and Theoretical Simulation on the Optical-Wave Refractive-Index Structure Constant Using Wind Profile Radar
Zhang Caiyun, Weng Ningquan, Gao Hui, Yao Yuancheng, Sun Gang, Liu Qing, and Xiao Liming
Turbulence gives effect on the light propagating in the atmosphere. There is an important parameter describing the turbulent strength which is the optical-wave refractive-index structure constant. Analyzing the echo of wind profile radar provides a new method to study turbulent strength. Calculating the turbulent dissiTurbulence gives effect on the light propagating in the atmosphere. There is an important parameter describing the turbulent strength which is the optical-wave refractive-index structure constant. Analyzing the echo of wind profile radar provides a new method to study turbulent strength. Calculating the turbulent dissipation rate and vertical gradient of mean velocity using wind profile radar, and combining the data of meteorological parameters, the optical-wave refractive-index structure constant C2n can be estimated. The order of magnitude of C2n is 10-18~10-13 m-2/3. The results are coincident to the actual condition, which proves that the new method is feasible. The effect of pressure gradient, temperature gradient and humidity on the refractive-index structure constant on different isobaric surfaces is simulated simultaneously. The results show that: pressure gradient can be ignored because of its small effect on C2n, while temperature gradient may have large effect on C2n, so there should be higher precision in actual measurement. The variation between 10% and 90% of relative humidity causes less than one order of magnitude of C2n, which demonstrates humidity can be ignored in clear air..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 301004 (2013)
Measuremental Method of Fugitive Dust Mass Emissions from Construction Activities Using Vertical-Scanning Lidar System
Shi Peng, Du Ke, Mu Chao, Wang Kai, and Wang Yang
Lidar is a powerful tool for detecting fugitive dust emissions. Here a method using vertical scanning micro pulse lidar (MPL) system to rapidly detect the two-dimensional mass distribution and the temporal variation of fugitive dust plumes in situ is descriped. In this method the backscattering signal from a building iLidar is a powerful tool for detecting fugitive dust emissions. Here a method using vertical scanning micro pulse lidar (MPL) system to rapidly detect the two-dimensional mass distribution and the temporal variation of fugitive dust plumes in situ is descriped. In this method the backscattering signal from a building in the far field is used as reference to provide a closure condition to lidar equation. The dust plume′s extinction coefficient profiles are determined from the raw MPL signals by inverting the lidar equation. The extinction coefficient profiles are then converted to mass concentration profiles using mass extinction efficiency fator, which is determined by Mie model and simultaneous size distribution measurements. This method quantifies the spatial and temporal variation of the dust′s PM10 and PM2.5 mass concentration when the dust plume passes across the laser light path. In addition, PM10 and PM2.5 emission factors for heavy-duty and light-duty vehicles traveling in the construction field are determined using this method. The mean PM10 emission factors for the heavy-duty and light-duty vehicles are 8.99×103 g/km and 1.75×103 g/km, respectively; the mean PM2.5 emission factors for the heavy-duty and light-duty vehicles are 4.57×102 g/km and 8.91×101 g/km, respectively. This novel method provides an in-situ rapid way to measure PM mass emissions from urban fugitive dust sources..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 301005 (2013)
Forecast of Atmosphere Optical Turbulence at Ali Site by Weather Research and Forecasting Model
Wang Hongshuai, Yao Yongqiang, and Liu Liyong
The optical turbulence forecasting by meteorological model can provide fundamental information for the flexible scheduling of observation and instruments of ground-based telescope, optimized the performance of adaptive optics and the opportunity of destroying object by laser. An optical turbulence forecast system has bThe optical turbulence forecasting by meteorological model can provide fundamental information for the flexible scheduling of observation and instruments of ground-based telescope, optimized the performance of adaptive optics and the opportunity of destroying object by laser. An optical turbulence forecast system has been established with the weather research and forecasting model. Based on this system and two optical turbulence parameterization methods, numerical model and analytical model, the meteorological parameters, C2n profiles and seeing at Ali site on November 06, 2011 are forecasted in advance on November 04, 05 and 06 respectively. Strong turbulence layers near ground, 2 km in boundary layer and 12 km in troposphere are discovered from the 6 forecasted results. The comparison between forecasted results and single star scintillation detection and ranging measurements shows that this forecasting system could provide the structure characteristics of Cn2 profiles. It also could provide the increasing trend of seeing results over night, similar to the result with differential image motion monitoring..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 301006 (2013)
Detection of Atmospheric SO2 and O3 Using Optical Fiber Coupling Long-Path Differential Optical Absorption Spectroscopy System with UV Light Emitting Diodes
Zheng Nina, Xie Pinhua, Ling Liuyi, Qin Min, Chan Kalok, Jiang Yu, Liu Wenqing, and Liu Jianguo
The measurements of atmospheric sulphur dioxide (SO2) and ozone (O3) using optical fiber based on light-emitting diode (LED) long-path differential optical absorption spectroscopy (LP-DOAS) system are presented. Two ultraviolet (UV) LED with different emission wavelength ranges are used as the light sources. The measurThe measurements of atmospheric sulphur dioxide (SO2) and ozone (O3) using optical fiber based on light-emitting diode (LED) long-path differential optical absorption spectroscopy (LP-DOAS) system are presented. Two ultraviolet (UV) LED with different emission wavelength ranges are used as the light sources. The measurement results are compared to the SO2 and O3 levels measured by the conventional LP-DOAS with xenon arc lamp light source. The comparison result shows that they are in good agreement, and the correlation coefficients of SO2 and O3 measurements are 0.987 and 0.992, respectively. With 700 m measurement path, the detection limit of SO2 and O3 are 0.8×10-9 and 7.4×10-9, respectively. This indicates that the optical fiber-based LP-DOAS improves the light coupling efficiency, and is feasible for the detection of ultraviolet absorbing trace gases using UV-LED as the light source..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 301007 (2013)
Detectors
Signal-to-Noise Ratio Properties of Multi-Pixel Photon Counter
Zhang Guoqing, Zhang Yingtang, Zhai Xuejun, Liu Hanchen, and Zhu Changjun
The signal-to-noise ratio formulas of a multi-pixel photon counter (MPPC) are obtained based on its photoelectric characteristic and experimental results, and by revising the traditional signal-to-noise ratio (RSN) formula of linear mode avalanche photodiode (APD). The method is used for random photon detection mode anThe signal-to-noise ratio formulas of a multi-pixel photon counter (MPPC) are obtained based on its photoelectric characteristic and experimental results, and by revising the traditional signal-to-noise ratio (RSN) formula of linear mode avalanche photodiode (APD). The method is used for random photon detection mode and short-pulse photon detection mode, respectively. The numerical calculation results using the obtained RSN formula are consistent with the experimental results. The numerical results show that the minimum detectable photon flux is of the order of 103 count·s-1, the minimum detectable power is about 10-15 W. Numerical analysis for the RSN formula of the short pulse photon detection mode is done. The results show that the RSN of the MPPC can be obviously improved by adjusting the photoelectron-number equivalent threshold of the MPPC. This method of the MPPC has its own advantage compared with the traditional photon detector. It has wide application prospect in the field of pulsed low-level light detection such as pulsed laser ranging and high-energy particle physics..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 304001 (2013)
X-Ray Pulsar Signal De-noising Using Lifting Scheme Wavelet
Liu Xiuping, Li Xiaoping, and Sun Haifeng
As the pulsar profile obtained through the folding of X-ray signal in a short time has low signal-to-noise ratio, a de-noising method based on lifting scheme is proposed for the X-ray pulsar signal. The model of noise reduction based lifting scheme is analyzed. And the pulsar profile is preprocessed by using the pre-deAs the pulsar profile obtained through the folding of X-ray signal in a short time has low signal-to-noise ratio, a de-noising method based on lifting scheme is proposed for the X-ray pulsar signal. The model of noise reduction based lifting scheme is analyzed. And the pulsar profile is preprocessed by using the pre-denoising model. The noise of the pulsar profile is reduced based on the lifting scheme with wavelet and the adaptive thresholding function. Some groups of measure data explored by Rossi X-ray timing explorer (RXTE) are applied for simulation analysis. The simulation results show that the signal-to-noise ratio of pulse profile can be improved, and that the proposed method has fast computational speed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 304002 (2013)
Diffraction and Gratings
Design Optical Fiber Telecommunication Grating Using Reciprocity Theorem Optimized Method
Zhang Shanwen, Ying Jianxin, and Gao Jianxiang
As a dispersing-type wavelength division multiplexer in optical fiber telecommunication, generally, grating needs to have high diffraction efficiency in near grazing incidence. According to traditional design method, optical fiber communication grating whose blazing angle is large is hard to be manufactured technicallyAs a dispersing-type wavelength division multiplexer in optical fiber telecommunication, generally, grating needs to have high diffraction efficiency in near grazing incidence. According to traditional design method, optical fiber communication grating whose blazing angle is large is hard to be manufactured technically. Based on grating electromagnetic theory, a design idea that makes use of grating reciprocity theorem to compute initializing value of grating groove, combined with diffraction-efficiency contour method to optimize grating groove, is presented. The results show that theoretical efficiency peak of -1 order of TM wave is 94.9% and measuring peak can reach 92.1% in C band. Compared to traditional design method, reciprocity theorem optimized method that reduces the degree of difficulty of manufacturing grating and improves diffraction efficiency, provides a better path of developing grating in near gazing incidence..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 305001 (2013)
Fiber Optics and Optical Communications
Fabrication of Low-Loss AgI/Ag Hollow Fibers for Laser Light Delivery in the Near Infrared Region
Zeng Xuan, Liu Binghong, He Yujing, Sun Bangshan, and Shi Yiwei
AgI/Ag hollow fibers have been fabricated and found applications in mid-infrared wavelength regions. However, it is a challenge to fabricate low-loss AgI/Ag hollow fiber in the near infrared region, because it is difficult to control the film thickness and surface roughness. Some improvements, including ethanol as the AgI/Ag hollow fibers have been fabricated and found applications in mid-infrared wavelength regions. However, it is a challenge to fabricate low-loss AgI/Ag hollow fiber in the near infrared region, because it is difficult to control the film thickness and surface roughness. Some improvements, including ethanol as the new iodine solvent, low iodination temperature, and fast flowing rate for the iodine solution with a vacuum pump, are proposed in order to coat a thin and smooth AgI film with a thickness of 70 nm. Low-loss AgI/Ag hollow fibers with various inner diameters are obtained for 1 μm wavelength band. The measured transmission loss is 1.15 dB/m for the 1.064 μm diode pumped solid state laser system. Fabrication parameters including iodine concentration and reaction temperature are discussed in detail. The transmission and bending loss properties of the AgI/Ag hollow fibers with various inner diameters in the near infrared region are evaluated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 306001 (2013)
Optoelectronic Hybrid Optical Clock Frequency Divider/Multiplier
Zhou Zhuya, Jiang Yang, Bai Guangfu, Xu Jing, Wang Shunyan, and Li Hengwen
A scheme of optoelectronic hybrid optical clock frequency divider/multiplier is proposed and analyzed. The optical clock signal frequency divider/multiplier is realized by feedback modulation after the photoelectric conversion. The procedure of the frequency divider is similar to the principle of D flip-flop, in which A scheme of optoelectronic hybrid optical clock frequency divider/multiplier is proposed and analyzed. The optical clock signal frequency divider/multiplier is realized by feedback modulation after the photoelectric conversion. The procedure of the frequency divider is similar to the principle of D flip-flop, in which the output signal is used to control the input signal. The frequency multiplication of optical clock is also implemented by simply changing the feedback sequence without replacing devices. According to signal processing in the time/frequency domain, the principle of frequency divider/multiplier is discussed respectively and the feasibility of the proposed scheme is demonstrated. In the experimental demonstration, 5 GHz optical/electric clock signal and 20 GHz optical clock signal are generated from a 10 GHz optical clock signal. The system has simple configuration, stable performance. It is transparent to the wavelength of the optical signal, and doesn′t need the optical, electrical filter. In this system, the optical/electrical signal can be output simultaneously, therefore it has good practicability and can easily cooperate with the subsequent signal processor..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 306002 (2013)
Analysis of the Sagnac Effect and Its Influence on the Accuracy of Time Transfer System by the Optical Fiber
Yu Longqiang, Lu Lin, Wang Rong, Jing Jisong, Wu Chuanxin, and Zhu Yong
Analyses have been done to explain the generation of the Sagnac effect in time transfer system over optical fiber. Mathematical expression of the time deviation, which is caused by Sagnac effect between any two points on the surface of the earth, is deducted in detail. Influences on the accuracy of the time transfer arAnalyses have been done to explain the generation of the Sagnac effect in time transfer system over optical fiber. Mathematical expression of the time deviation, which is caused by Sagnac effect between any two points on the surface of the earth, is deducted in detail. Influences on the accuracy of the time transfer are studied deliberately by simulation. It is demonstrated that the time deviation is decided by the latitude and the course of the fiber link and it may be larger than 1 ns for a long haul. So accurate time delay compensation or calibration should be concerned in terrestrial time transfer system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 306003 (2013)
Fourier Optics and Signal Processing
Investigation on Light Intensity Distribution of Raman-Nath Acousto-Optic Diffraction Based on Fourier Analysis
Ruan Lifeng, Tang Zhilie, and Liu Xueling
In order to explore the physics essence of the imaging principle of the ultrasonic standing waves in Raman-Nath diffraction and clarify the confusion of the theory, a new method based on Fourier optics is proposed. The optical field of a laser beam vertically passing through the ultrasonic standing waves in Raman-Nath In order to explore the physics essence of the imaging principle of the ultrasonic standing waves in Raman-Nath diffraction and clarify the confusion of the theory, a new method based on Fourier optics is proposed. The optical field of a laser beam vertically passing through the ultrasonic standing waves in Raman-Nath diffraction is analyzed via this method, which contains a series of incoherent light with different frequencies. The intensity distribution of this field is obtained by linear superposition of incoherent light of different frequencies after calculating the individual interference light intensity distribution. This expression proves the correctness of an existing acoustic velocity measuring method that has not been testified. The simplification of this expression according to actual conditions in the experiment is also accomplished and it is proved experimentally..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 307001 (2013)
Additional Key Rotation Multiplexing Encryption Using Joint Transform Correlator Architecture
Qin Yi, Lü Xiaodong, Gong Qiong, and Jiang Hualong
A key rotation multiplexing method to the modified joint transform correlator arrangement is introduced. For encryption, the rounding key with a certain rotation angle is assigned to each image to be encrypted to generate a corresponding joint power spectrum. Then the final encryption result, namely multiplexed joint pA key rotation multiplexing method to the modified joint transform correlator arrangement is introduced. For encryption, the rounding key with a certain rotation angle is assigned to each image to be encrypted to generate a corresponding joint power spectrum. Then the final encryption result, namely multiplexed joint power spectrum, will be obtained by summing the above mentioned joint power spectrum. The decryption of the multiplexed joint power spectrum with the correct rotation angle of the additional key will show the corresponding primary images. Theoretical analysis and computer simulations reveal that rotation angle of the additional key is a valid parameter to perform image multiplexing encoding with the modified joint transform correlator architecture. Also, computer simulations to investigate how the number of encrypted images affects the decryption quality are performed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 307002 (2013)
Geometric Optics
Arrangement and Shape Optimization of Solar Concentrating Receivers Using Monte Carlo Method
Ma Hongcai, Jin Guang, Zhong Xing, and Ren Bingwen
Uniform radiation flux distribution in the received surface is crucial for the performance and conversion efficiency of a solar concentrating system. In order to improve the uniformity of radiation flux distribution in the receiving surface, the arrangement and shape optimization of solar concentrating receivers is proUniform radiation flux distribution in the received surface is crucial for the performance and conversion efficiency of a solar concentrating system. In order to improve the uniformity of radiation flux distribution in the receiving surface, the arrangement and shape optimization of solar concentrating receivers is proposed. Considering the sun shape, the radiation flux distribution is determined by Monte Carlo ray-tracing method, and an optimization model is established, which takes the receiver aperture size as the constraint condition and aims at the highest uniformity of radiation flux distribution combing Kiefer-Wolfowitz algorithm. We take a linear parabolic-trough concentrating system for example, resulting in the most uniform intensity distribution while achieving a high energy reception of 78.25%, which testifies the validity of this optimization procedure. The optimization procedure computes more efficiently than the traditional trial-and-error methodology, and the obtained solutions are also near optimal..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 308001 (2013)
Imaging Systems
Deformable Mirror Control Algorithm Based on the Phase Correction at the Actuator Position
Guo Ailin, Zhu Haidong, Yang Zeping, Tang Shiwang, Xie Xinglong, and Zhu Jianqiang
One core study of adaptive optics wavefront control algorithm is to obtain the loaded voltage of each actuator rapidly and accurately. The algorithm based on the phase correction at the actuator position can dramatically reduce the data calculation, achieve the required phase precision with less convergence steps and rOne core study of adaptive optics wavefront control algorithm is to obtain the loaded voltage of each actuator rapidly and accurately. The algorithm based on the phase correction at the actuator position can dramatically reduce the data calculation, achieve the required phase precision with less convergence steps and realize the high-speed real-time control of the deformable mirror. Based on this algorithm, the calculation model for the phase control of 45 actuators deformable mirror of the SG-II update laser facility is set up. The simulation of the 2nd～36th items of Zernike polynomial aberrations [peak-to-valley (PV) value of 2 μm] shows that the phase correction precision of 0.01 μm can be achieved within 9 steps. The fitted shape of the first 15 items of Zernike polynomial aberrations shows that the aberration control ability of the deformable mirror can meet the requirements of the laser facility..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 311001 (2013)
Performance Evaluation Method of the Active Near-Infrared Imaging System Based on Equivalent Lighting
Song Junru, Wang Xia, Jin Weiqi, Lu Yuhua, Liu Jianxuan, and Li Hongsheng
Active near-infrared imaging system used for traffic monitoring and regional security monitoring is an important application of night vision system. The function range of night vision system is an important performance indicator and the main basis for system design. A method for evaluating the function range of system Active near-infrared imaging system used for traffic monitoring and regional security monitoring is an important application of night vision system. The function range of night vision system is an important performance indicator and the main basis for system design. A method for evaluating the function range of system is proposed according to the needs of the design and analysis of active near-infrared imaging system. The method can determine the detection capability of system on the target at a given distance. Based on the calculation of the distribution of irradiance on the target at a given distance according to the atmospheric transmission theory, the irradiance is simulated utilizing the principle of equivalent lighting at a short distance. Then the detection capability of the system on the target at a given distance is evaluated according to Johnson criteria and imaging theory. The corresponding tests are carried out, and the tested results are compared with the actual outdoor measurement results. The method is applicable for general optical imaging systems..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 311002 (2013)
Speckle Characteristics of Laser Radar Polarization Imaging and Despecking Algorithm
Wen Donghai, Jiang Yuesong, Zhang Xuguo, Zhang Yanzhong, and Hua Houqiang
The theoretical and the experimental investigations of the laser polarization imaging system of speckle statistical characteristics and speckle removing method are conducted. A probability distribution model for speckle intensity of laser active polarization imaging system by using Müller matrix is proposed. AccorThe theoretical and the experimental investigations of the laser polarization imaging system of speckle statistical characteristics and speckle removing method are conducted. A probability distribution model for speckle intensity of laser active polarization imaging system by using Müller matrix is proposed. According to modern charge coupled device (CCD) imaging characteristics, through comparison of speckle and pixel size speckles are divided into two kinds, namely small speckle and big speckle. The normalized variance of speckle is linear to pixel, and the mean value of speckle is irrelevant to pixel. A unified speckle noise probability model, namely the improved Gamma distribution model is proposed. Based on this model, the improved Bayesian nonlocal algorithm is presented. The despeckling results show that equivalent number of looks and edge preserve index outperform those of traditional methods..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 311003 (2013)
Calculation of Photometric Inefficiency for All Shapes of Cold Shields with Superposition Integral Method
Yang Kaiyu, Jin Ning, Xu Man, Cao Ling, and Su Junhong
The aperture shapes of cold shields have direct effects on stray light suppressing in infrared systems. The concept of photometric inefficiency is introduced to evaluate the cold shield shapes′ ability of suppressing stray light. A creative idea and algorithm of using the superposition integral method to accurately calThe aperture shapes of cold shields have direct effects on stray light suppressing in infrared systems. The concept of photometric inefficiency is introduced to evaluate the cold shield shapes′ ability of suppressing stray light. A creative idea and algorithm of using the superposition integral method to accurately calculate the photometric inefficiency for all shapes of cold shields are proposed. Based on the method, a mathematical model is built. A typical 288×4 thermal imager is chosen as an instance to be calculated by the program. Compared with the results calculated by the ray tracing statistical method, it is concluded that superposition integral method has accordant results to the ray tracing statistical method, which has far higher speed of computation than ray tracing statistical method when they get the same accuracy..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 311004 (2013)
Instrumentation, Measurement and Metrology
A Dynamic, Real-Time, High-Precision Optical Method of Level Attitude Measurement
Feng Xiaoyong, Zhu Weikang, Qiao Yanfeng, Li Huifen, and Liu Xinming
To measure the level attitude of moving carriers (such as vehicles, ships, aircraft, etc.) in real-time and highly precisely, based on liquid′s automatic level, a method combining high-precision optical angle measurement, inertial synchronous multiplexing platform and level error detection tool is proposed and tested oTo measure the level attitude of moving carriers (such as vehicles, ships, aircraft, etc.) in real-time and highly precisely, based on liquid′s automatic level, a method combining high-precision optical angle measurement, inertial synchronous multiplexing platform and level error detection tool is proposed and tested on a docking ship. The test result confirms the correctness, effectiveness and feasibility of this method. The difference D-value between the level attitude measurements of test equipment and inertial equipment is not larger than 2.0″ [root mean square (RMS)]. This method can be used in high-precision measurement of level attitude, measurement of structural deformation and accuracy evaluation of inertial system of moving carriers such as different kinds of military weapon launching platforms..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 312001 (2013)
Application of Hybrid Mutation Neural Network and Fuzzy Adaptive Particle-Swarm Optimization Algorithm in Testing of Micro-Drill
Ge Dongyuan, Yao Xifan, and Xiang Wenjiang
According to the measurement requirements of micro-drill, a new approach based on hybrid mutation neural network integrated with fuzzy adaptive particle-swarm optimization (PSO) for fitting of micro-drill′s feature curves is presented. The network is designed to coincide with the fitted equation in experiment. After thAccording to the measurement requirements of micro-drill, a new approach based on hybrid mutation neural network integrated with fuzzy adaptive particle-swarm optimization (PSO) for fitting of micro-drill′s feature curves is presented. The network is designed to coincide with the fitted equation in experiment. After the training of network and every iteration of particle individual, the obtained neural weights are normalized to form a unit weight vector, which is equivalent to a special mutation operation for individuals. At the same time, the fuzzy adaptive PSO is integrated into the solving algorithm to get the global optimization solution. And the inertia factor of PSO is tuned self-adaptively by adopting fuzzy logic reasoning according to the characteristic of particle′s motion trajectory in longitudinal direction and lateral direction. When the solving system comes to the global equilibrium point, the position vector of the best particle is used to obtain the expression coefficients of the fitted equation. Then in the light of the fitting equations, the structural parameters and flank faults such as core width, rounded corners, chips of the micro-drill and so on can be obtained easily. Compared with the traditional test approaches such as least square method, experimental results show that the proposed approach provides a new scheme for the curves fitting of micro-drill and other work-pieces with high measurement precision..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 312002 (2013)
Method Based on Carrier Squeezing Interferometry for Suppressing Phase Errors from Inaccurate Phase Shift in a Φ600 Fizeau Interferometer
Li Jinpeng, Chen Lei, Li Bo, Zhu Ronggang, and Li Jianxin
A method using in a phase-shifting Φ600 Fizeau interferometer is proposed to suppress phase errors from inaccurate wavelength increment and vibration. The data of four interferograms are reconstructed by column and combined to a single spatial-temporal fringes (STF) image. In the spectrum of the STF, the phase lobe andA method using in a phase-shifting Φ600 Fizeau interferometer is proposed to suppress phase errors from inaccurate wavelength increment and vibration. The data of four interferograms are reconstructed by column and combined to a single spatial-temporal fringes (STF) image. In the spectrum of the STF, the phase lobe and error lobe are separated by introducing linear carrier into original interferograms. The component related to phase distribution can be selected by filtering and the phase can be reconstructed accurately. Considering vibration and inaccurate wavelength increment, the simulation result indicates that the accuracy using this method is 10 times of that using traditional phase shifting-algorithm. Its validation is verified by experiments, where an accuracy of 0.0066λ is obtained. This method can be used to realize suppression of phase errors from inaccurate wavelength increment and vibration in a Φ600 Fizeau interferometer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 312003 (2013)
Research on Dimension Measurement of Large Size Ceramic Floor Tiles Based on Machine Vision
Lu Qinghua, Xu Chongchun, Wang Hua, Zhang Xianming, and Fan Yanbin
A dimensional measurement method with high accuracy for large size ceramic floor tiles based on the machine vision using single camera is presented. An optical system is designed, whose reflective light path consists of multiple mirrors. The images of four corners of the ceramic floor tiles are acquired by the single cA dimensional measurement method with high accuracy for large size ceramic floor tiles based on the machine vision using single camera is presented. An optical system is designed, whose reflective light path consists of multiple mirrors. The images of four corners of the ceramic floor tiles are acquired by the single camera rather than the whole image, thus the asynchronous problem caused by multiple cameras acquiring the measured images is solved. Then the accuracy of measurement is improved. An algorithm for the tiles measurement is proposed based on boundary searching fitting and dynamic compensation. In such an algorithm, considering shift and rotation of the tiles in practical production, the dimension of diagonals and sidelines with high accuracy can be obtained by using the images of the four corners, which boundary searching of the measured images and dynamic compensation of measured dimension is performed. The measured standard deviation is less than 0.02 mm, and the repeatability approaches 0.06 mm when measuring dimension of diagonals and sidelines of 600 mm×600 mm and 800 mm×800 mm tiles. The experimental results show that the measurement system can be widely used in ceramic floor tiles manufacturers with high quality..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 312004 (2013)
Study of Wide-Angle Staring Laser Threat Detection System Based on Grating Diffraction
Wang Long, Wang Yongzhong, Shen Xueju, and He Yongqiang
In order to detect both direction and wavelength of attacking incident laser beam, a wide-angle staring laser threat detection system based on grating diffraction is designed, analytic expressions of laser direction and wavelength are deduced, and imaging rule of the system is analyzed. The detecting ability of the sysIn order to detect both direction and wavelength of attacking incident laser beam, a wide-angle staring laser threat detection system based on grating diffraction is designed, analytic expressions of laser direction and wavelength are deduced, and imaging rule of the system is analyzed. The detecting ability of the system is put to test by utilizing 1064 nm pulse laser. Results show that incident laser beam is imaged to three equal-interval bright spots by this detection system, and the direction and wavelength of incident laser can be calculated based on the coordinate of middle spot and the interval of two adjacent spots. Optical aberration of fish-eye lens makes the system′s imaging spots larger, more blurred and distort to cone with increase of incident angle of the laser beam. Half angle of vision of the designed system is 35°, and both direction and wavelength of incident laser beam can be detected effectively with the maximum detection errors of 1.5°and 60 nm, respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 312005 (2013)
Laser Feedback Interference System Based on Phase-Freezing Technology
Liu Huilan, Cao Wenjuan, and Wang Wei
A laser feedback interferometry combined with phase-freezing technology is researched. To verify the technology and its measurement resolution, a micro-displacement measurement system is designed. In the system, phase modulator is added to modulate the external cavity phase and phase-freezing technology is used for samA laser feedback interferometry combined with phase-freezing technology is researched. To verify the technology and its measurement resolution, a micro-displacement measurement system is designed. In the system, phase modulator is added to modulate the external cavity phase and phase-freezing technology is used for sampling and demodulation to reconstruct the displacement information of the external target. Measurement system model is established. Modulation-demodulation algorithm simulation based on phase-freezing technology and the displacement measurement experiment are made. Comparing the actual displacement of the external target and the system reconstruction result, the accuracy of simulation and the feasibility of system are verified. The measurement peak-valley (PV) value relative error is less than 3%. It is drawn that the method can effectively improve the measurement resolution of system and achieve the real-time measurement of micro-displacement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 312006 (2013)
Lasers and Laser Optics
Optimized Design of Optically Pumped Vertical-External-Cavity Surface-Emitting Lasers Based on the Gain Characteristics
Hua Lingling, and Yang Yang
The gain characteristics of the optically pumped vertical external cavity surface emitting lasers is introduced in detail. To take the InGaAs/AlGaAs strained quantum wells as an example, a complete system model is established which considers all the effects of the band-edge offset, band structure and gain material. TheThe gain characteristics of the optically pumped vertical external cavity surface emitting lasers is introduced in detail. To take the InGaAs/AlGaAs strained quantum wells as an example, a complete system model is established which considers all the effects of the band-edge offset, band structure and gain material. The Model-Solid model is used to determine the band-edge-offset ratios, and then the parabolic approximation of conduction band and the 6×6 Luttinger Hamiltonian of valence band are used to calculate the energy-band structure and material gain. Based on the analysis of the characteristics of material gain, the active region of a 1 μm wavelength band quantum well is optimized, and the quantum well width, well depth, and configuration of the well are respectively optimized, then the optimum selections of which are obtained. The calculated results provide a theoretical basis for optimized designing of optically pumped vertical external cavity surface emitting lasers..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 314001 (2013)
Machine Vision
Femtosecond-Laser-Written Waveguide in Magneto-Optical Glass
Hou Fang, Li Weinan, Bai Jing, Zhou Kaiming, Long Xuewen, Hui Rongqing, Zhang Xiaolin, and Cheng Guanghua
Femtosecond-laser-induced refractive index modification has provided a flexible tool to fabricate three-dimensional photonic devices. Magneto-optical (MO) glass is widely used in integrated optics because of its Faraday rotation. Femtosecond laser at 1 kHz repetion rate is used to write waveguides in MO glass, then neaFemtosecond-laser-induced refractive index modification has provided a flexible tool to fabricate three-dimensional photonic devices. Magneto-optical (MO) glass is widely used in integrated optics because of its Faraday rotation. Femtosecond laser at 1 kHz repetion rate is used to write waveguides in MO glass, then near-field modes of waveguides written by different focusing parameters are measured, and the refractive index changes in the written regions and mode field diameters as functions of writing parameters (scanning speed and writing power) are obtained, which show a writing window of waveguide formation in MO glass. Experimental results show that the Verdet constant in the written region only has a slight reduction (about 2.8%) under a special writing parameter set (10×, objective scanning speed 40 μm/s, laser power 3 mW); the loss of the waveguide is 1.53 dB/cm, and its mode field diameter is 10 μm injected by 980 nm, so it is practicable to couple light from fiber into waveguide written by femtosecond laser..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 314002 (2013)
Novel Calibration Method for Stereo Vision Sensor Using Flexible Target
Liu Zhen, and Shang Yanna
In order to solve the calibration problem of the stereo vision sensor with large field-of-view (FOV), a novel calibration method using flexible target is proposed. According to the stereo vision sensors′ FOV, several small planar targets are combined by the rigid connection device. The flexible target is moved in frontIn order to solve the calibration problem of the stereo vision sensor with large field-of-view (FOV), a novel calibration method using flexible target is proposed. According to the stereo vision sensors′ FOV, several small planar targets are combined by the rigid connection device. The flexible target is moved in front of the stereo vision sensor several times (at least two times) without restriction, and the transformation matrix between the two cameras is solved according to the invariance of the relative positions between small planar targets. The transformation matrix is optimized using the nonlinear optimization method. Experimental result shows that the accuracy of the proposed method is higher than that of a small target, and close to that of a large target..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 315001 (2013)
Mismatching Marked Points Correction Method Based on Random Sample Consensus Algorithm
Lei Yuzhen, Li Zhongwei, Zhong Kai, and Wang Congjun
It is often needed to paste many marked points to realize auto-registration in the process of large parts three-dimensional (3D) measurement. Because of the randomness of artificially pasted marked points and noise factors, mismatching marked points often exist in auto-matching, which affect the stability of point-clouIt is often needed to paste many marked points to realize auto-registration in the process of large parts three-dimensional (3D) measurement. Because of the randomness of artificially pasted marked points and noise factors, mismatching marked points often exist in auto-matching, which affect the stability of point-clouds auto-registration for repeated measurements. For this problem, a method is presented which uses random sample consensus (RANSAC) algorithm to remove the mismatching marked points based on the auto-matching of marked points. The method divides all matching marked points into inner points and outer points according to the selected target model and related criteria, calculates the current optimum target model parameters using the inner points and finally calculates the best parameters after a certain times of random sampling. It effectively removes the distance and noise mismatching marked points which are generated in the process of point-clouds auto-registration of large parts. Simulation experiment and registration examples demonstrate that the method is practicable and improves the stability of point-clouds auto-registration effectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 315002 (2013)
Fast Line Segment Detection Based on Edge Connecting
Dong Jing, Yang Xia, and Yu Qifeng
Linear characteristic, which is the basic element of image understanding and analysis, gives important information about the geometric content of images. A fast algorithm based on edge connecting is proposed for detecting line segments in image which contains many artificial objects. The Canny detector is used for edgeLinear characteristic, which is the basic element of image understanding and analysis, gives important information about the geometric content of images. A fast algorithm based on edge connecting is proposed for detecting line segments in image which contains many artificial objects. The Canny detector is used for edge extraction. An edge connecting strategy which takes into account both the principal orientation and gradient direction is used for selecting candidates of line segments. Noise and curves can be removed from the candidates according to the coherence of principal and straightness errors. After that, the least squares method is used for extracting line segments from the rest candidates. The test result implies that the proposed algorithm is better than the classical component algorithms, such as Hough transform, phase grouping and line detection by principal component analysis, in accuracy and speed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 315003 (2013)
Stereo Matching Algorithm with Graph Cuts Based on Adaptive Watershed
Zhu Shiping, and Yang Liu
Based on the existing graph cut algorithms, a stereo matching method which is based on adaptive watershed algorithm and non-parametric depth smoothing model to create an energy equation of graph cut is designed. A novel adaptive local threshold method is proposed, which is applied to region integration by combining theBased on the existing graph cut algorithms, a stereo matching method which is based on adaptive watershed algorithm and non-parametric depth smoothing model to create an energy equation of graph cut is designed. A novel adaptive local threshold method is proposed, which is applied to region integration by combining the watershed with Prim′s algorithm. The proposed method selects the pixels with same brightness as a feature vector and forms pixels group, thus two or more images can be matched in the pixels group layer of feature region, then the amount of data can be greatly reduced. When the energy equation is minimized, pixels groups layer can be used to optimize the α-expansion algorithm, and reduce the running time. Experimental results indicate that the error match ratios of all regions, non-occluded area and depth discontinuity regions are all less than 8.5%. The proposed algorithm is in the place of 19 among all the 135 algorithms in Middlebury testing platform..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 315004 (2013)
Optical Design and Fabrication
Optical System Design of a Spaceborne Broadband Far Ultraviolet Hyperspectral Imager
Xue Qingsheng
According to the application requirements for remote sensing of upper atmosphere, a reflective optical system of spaceborne far ultraviolet hyperspectral imager is designed. Which is composed of a scan mirror, an off-axis parabolic telescope and a toroidal grating spectrometer. An aberration-correction method for concaAccording to the application requirements for remote sensing of upper atmosphere, a reflective optical system of spaceborne far ultraviolet hyperspectral imager is designed. Which is composed of a scan mirror, an off-axis parabolic telescope and a toroidal grating spectrometer. An aberration-correction method for concave toroidal grating is developed. The initial parameters are solved based on the geometrical aberration theory of concave grating and then optimized using the optical design software Zemax, and the toroidal gating spectrometer is designed. The root mean square of spot radius is less than 16 μm in the working waveband. Aberration is corrected simultaneously in broadband and the requirement of spectral resolution of 0.6 nm is satisfied, which indicates the aberration-correction method is feasible. Ray tracing and analysing are performed by Zemax software. Analyzed results demonstrate that the modulation transfer function for different wavelength is more than 0.8, which satisfies the design requirements. The construction is compact and suitable for application in space remote sensing..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 322001 (2013)
Design of Fore Optical System in Space-Borne Differential Optical Absorption Spectrometer for Atmospheric Trace Gas Monitoring
Si Fuqi, Jiang Yu, Jiang Qingwu, Xue Hui, Zhou Haijin, and Liu Wenqing
Space-borne differential optical absorption spectrometer is used for atmospheric trace gas distribution monitoring through acquiring high accuracy ultraviolet/visible (UV/VIS) radiation scattered or reflected by air or earth surface. To achieve the goals of large view angle, wide UV/VIS waveband detection, high spectraSpace-borne differential optical absorption spectrometer is used for atmospheric trace gas distribution monitoring through acquiring high accuracy ultraviolet/visible (UV/VIS) radiation scattered or reflected by air or earth surface. To achieve the goals of large view angle, wide UV/VIS waveband detection, high spectral resolution and compact structure in space, a fore optical system is designed. It includes fore-optics telescope and relay optical system. To detect viewing field at 114° in cross-orbit direction, fore-optics telescope with two pieces of off-axis spherical mirrors is designed. Relay optical system consists of relay mirror, color-separation filters, and relay lens, which separates the incident light into four spectral channels covering 240~710 nm. Then we import each beam of light into corresponding spectral imaging channels respectively. The design result shows that the fore optical system works efficiently inside the field of view for both UV and VIS waveband, providing good imaging quality. That makes it possible to implement high spectral resolution of subsequent systems. The fore optical system has more compact structure and lighter weight comparing with other products. It can meet the requirement of spaceborne and airborne platforms without using a scan mirror..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 322002 (2013)
Optical Devices
Terahertz Multiband Terahertz Filter Based on Three Nested Closed Rings
Wang Wentao, Liu Jianjun, and Hong Zhi
Terahertz filter can be used for various applications such as imaging, spectroscopy and sensing. We propose and fabricate a terahertz multiband filter using three nested closed-ring resonators (CRRs) on polyimide substrate. We numerically analyze the physical origin of the multispectral response and discuss the dependeTerahertz filter can be used for various applications such as imaging, spectroscopy and sensing. We propose and fabricate a terahertz multiband filter using three nested closed-ring resonators (CRRs) on polyimide substrate. We numerically analyze the physical origin of the multispectral response and discuss the dependence of the resonance frequencies on the geometrical parameters of the closed rings. It is found that the three resonant peaks of the proposed filter originate from not only the dipole electric response of the three rings and the magnetic response between the adjacent rings, but also the effect from inner or outer CRR. The performance of the filter is measured by terahertz time-domain spectroscopy (TDS), and the experimental results show three distinct resonant peaks at 0.33, 0.68, 1.13 THz, which are in good agreement with simulations..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 323001 (2013)
Design and Fabrication of 650 nm Arrayed Waveguide Grating
Han Chao, Yue Yuanbin, Zhao Shimin, Chen Changming, and Zhang Daming
Because “the last kilometer” problem of the optical communication network is expected to be solved by the 650 nm polymer optical fiber system, a 16×16 channel polymer array waveguide grating (AWG) wavelength division multiplexer is successfully fabricated to match the system. The design of the device is chosen as Because “the last kilometer” problem of the optical communication network is expected to be solved by the 650 nm polymer optical fiber system, a 16×16 channel polymer array waveguide grating (AWG) wavelength division multiplexer is successfully fabricated to match the system. The design of the device is chosen as rectangular waveguide structure, while the refractive indices of the core layer and cladding layer are selected as 1.4888 and 1.482, respectively. By OptiBPM software, it is obtained that the channel insert loss is from 2.3 dB to 5.1 dB, the crosstalk level is -24 dB, and the channel spacing is 1.6 nm. For the fabrication of device, the polymethyl methacrylate (PMMA) material is choosed which is synthesized in our laboratory. By the ultraviolet (UV) lithography and inductively coupled plasma (ICP) etching process, a fine waveguide morphology is obtained, and finally the sample′s area is 4 cm×3 cm. The polymer optical fiber (POF) is used to couple the 650 nm visible light into AWG device for testing and excellent multiplexing/de-multiplexing performances are achieved. The AWG wavelength division multiplexer in red-light wave band will play an important role in the future optical communication..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 323002 (2013)
Optical System Error Analysis of High Accuracy Star Trackers
Sun Ting, Xing Fei, and You Zheng
A synthetic error analysis approach is proposed in detail based on error source weight analysis and comparison of the star tracker using Monte Carlo method. It can avoid long and cumbersome theoretical derivation, which can provide error propagation relation of the star tracker intuitively and systematacially. The erroA synthetic error analysis approach is proposed in detail based on error source weight analysis and comparison of the star tracker using Monte Carlo method. It can avoid long and cumbersome theoretical derivation, which can provide error propagation relation of the star tracker intuitively and systematacially. The error propagation model can provide foundation and rule for optimization design, calibration and compensation of the star tracker. Simulation consequences prove that the systematic analysis is adequate and precise, which can provides important guarantee for design and manufacture of high accuracy star trackers..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 323003 (2013)
Optical Simulation Based on P3HTPCBM Bulk-Heterojunction Solar Cells: a Comparison of Normal and Inverted Structures of Device
Cao Jing, Zhan Zhen, and Liu Pengyi
Optical model based on transfer matrix method is employed to investigate the effects of active layer thickness and the configuration on the performance of organic solar cells based on P3HTPCBM. Simulation result reveals that short circuit current density increases with active layer thickness and performance of invertedOptical model based on transfer matrix method is employed to investigate the effects of active layer thickness and the configuration on the performance of organic solar cells based on P3HTPCBM. Simulation result reveals that short circuit current density increases with active layer thickness and performance of inverted structure device is superior to normal one. Interference effect has a great influence on optical electric-field strength distribution and the device performance. The short-circuit current density and optical electronic field distribution in two structures of the device are calculated to decide the optimal device configuration. It is found that the inverted organic solar cell device with 225 nm thick P3HTPCBM shows the highest performance allowing achievement of short-circuit current density for 15.5 mA/cm2, efficiency for 5.77%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 323004 (2013)
Fabrications of White Organic Light-Emitting Device Based on Fluorescent Sub-Monolayer Combine with Phosphorescent Doping Layer
Yang Huishan
White organic light-emitting device (WOLED) based on fluorescent sub-monolayer combining with phosphorescent doping layer is fabricated, in which fluorescent material 4,4′-bis(2,2′-diphenyl vinyl)-1,1′-biphenyl (DPVBi) acts as blue emitter layer, sub-monolayer ［2-methyl-6- ［2-(2, 3, 6, 7-tetrahydro-1H, 5H-benzo［ij］ quiWhite organic light-emitting device (WOLED) based on fluorescent sub-monolayer combining with phosphorescent doping layer is fabricated, in which fluorescent material 4,4′-bis(2,2′-diphenyl vinyl)-1,1′-biphenyl (DPVBi) acts as blue emitter layer, sub-monolayer ［2-methyl-6- ［2-(2, 3, 6, 7-tetrahydro-1H, 5H-benzo［ij］ quinolizin-9-yl) ethenyl］-4H-pyran-4-ylidene］ propane-dinitrile (DCM2) inserted in the blue emitter layer acts as red emitter layer, fac tris (2-phenylpyridine) iridium ［Ir(ppy)3］ doped into 4,4′-N,N′-dicarbazole-biphenyl(CBP) host acts as green emitter layer, respectively. The structure of device is ITO / NPB（40 nm ）/DPVBi (8 nm) /DCM2(d)/CBPIr(ppy)3 8% (15 nm)/4, 7 -diphenyl-1, 10-phenanthroline (BPhen) (60 nm)/LiF (1 nm)/Al (200 nm). The device performance is controlled by varying the thickness of DCM2. The maximum current efficiency and maximum luminance of the device with the DCM2 thickness of 0.05 nm DCM2 are 7.60 cd/A, 15 420 cd/m2, respectively. The commission international eclairage (CIE) color coordinates of the device vary from (0.34, 0.44) at 4 V to (0.27, 0.33) at 12 V. In order to further improve the performance of WOLED, the BPhen is used as exciton block-layer to the WOLED, the maximum current efficiency and maximum luminance of the device with BPhen thickness of 5 nm are 10.56 cd/A at 4 V, 25960 cd/m2 at 13 V, respectively. The CIE color coordinates of the device vary from (0.34, 0.44) at 4 V to (0.28, 0.36) at 12 V that are general within the white region. The results show that, compared with that of without exciton block- layer, the devices employing exciton block-layer yield higher device performance as well as comparatively stable electroluminescence spectra and CIE color coordinates results stable white emission..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 323005 (2013)
Physical Optics
Analysis of Phase on Axis of the Bessel Beam and Self-Imaged Bottle Beam
Wu Fengtie, Cheng Zhiming, Wang Tao, and Pu Jixiong
Phases of Bessel beam and self-imaged bottle beam along propagation axis are analyzed. Phases of ideal Bessel beam and Bessel beam generated by axicon along propagation axis are periodic saw-toothed distribution after analysis with diffraction theory. And phase of self-imaged bottle beam generated by interference of twPhases of Bessel beam and self-imaged bottle beam along propagation axis are analyzed. Phases of ideal Bessel beam and Bessel beam generated by axicon along propagation axis are periodic saw-toothed distribution after analysis with diffraction theory. And phase of self-imaged bottle beam generated by interference of two Bessel beams is also saw-toothed distribution, while phase singularity is found at the zero intensity position. In simulation experiment, the minimum intensity of self-imaged bottle beam on axis is not zero, therefore there is not phase singularity on axis. The result of research is valuable in generating self-imaged bottle beam by phase modulation, whose dark field is zero..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 326001 (2013)
Novel Method to Detect the Orbital Angular Momentum in Optical Vortex Beams
Liu Man
The intensity and phase distributions of speckle fields on the near-field plane generated by the scattering of Laguerre-Gaussian beam from the weak random scattering screen are simulated. It is found that the spot profiles are similar to the peacock feather in intensity distributions of speckle fields, and those spots The intensity and phase distributions of speckle fields on the near-field plane generated by the scattering of Laguerre-Gaussian beam from the weak random scattering screen are simulated. It is found that the spot profiles are similar to the peacock feather in intensity distributions of speckle fields, and those spots are uniformly distributed around the central dark spots. The number of spots is related to the orbital angular momentum quantum number of the vortex beams. The orbital angular momentum quantum number is an integer or fractional, while whether it is integer or fractional, the number spots is four times of the orbital angular momentum quantum number. In the case of fractional vortex beam, there is a spot along the horizontal direction uniformly split into two petals. This method can be used to detect the orbital angular momentum quantum number of vortex beams..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 326002 (2013)
Remote Sensing and Sensors
Ladar Data Filtering Method Based on Improved Progressive Multi-Scale Mathematic Morphology
Zhao Mingbo, He Jun, Tian Junsheng, and Fu Qiang
Ladar point-cloud data filtering is basis and critical steps of the ladar data processing. Filtering algorithm based on mathematical morphology is applied widely. But the existing filtering algorithms have some problems when processing point-cloud data which contains some blank region of large area. To solve these probLadar point-cloud data filtering is basis and critical steps of the ladar data processing. Filtering algorithm based on mathematical morphology is applied widely. But the existing filtering algorithms have some problems when processing point-cloud data which contains some blank region of large area. To solve these problems, an improved progressive multi-scale mathematical morphology filtering algorithm is proposed. It deals with the blank region by improving morphological opening operation. According to basic principles of mathematical morphology, feasibility of improved morphological opening operation is proved. Then basic steps of the proposed algorithm are elaborated, and performance characteristics are analyzed. The proposed algorithm is verified experimentally by using simulation data and public test data. Experimental results show that the proposed algorithm can perfectly filter point-cloud data which contains some blank region of large area, and it has better filtering performance compared with other representative filtering algorithm in most cases..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 328001 (2013)
Design of Parameters of Shack-Hartmann Wave-Front Sensor for Laser-Beam Quality Measurement
Liu Minshi, Wang Xiaoman, Jing Wenbo, and Wang Bin
Shack-Hartmann wave-front sensor has been widely used in laser-beam quality measurement, for its acquisition of intensity and phase of laser beam simultaneously. It is an important procedure in the construction of the measurement system to design the system parameters of the Shack-Hartmann wave-front sensor according tShack-Hartmann wave-front sensor has been widely used in laser-beam quality measurement, for its acquisition of intensity and phase of laser beam simultaneously. It is an important procedure in the construction of the measurement system to design the system parameters of the Shack-Hartmann wave-front sensor according to the requirements in actual laser beam test. The parameters of the Shack-Hartmann wave-front sensor are designed with considerations of the requirements of the precision, sensitivity and dynamic range, as well as the mutual restraints among them. The design procedure is given and the laser-beam measurement system is constructed successfully with the designed parameters. The actual Shack-Hartmann wave-front sensor in single aperture with dynamic range of 3.7λ (λ=632.8 nm), sensitivity of 0.01λ, and Fresnel number of 2.468, satisfies the requirements of the laser-beam measurements in practice..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 328002 (2013)
Spectroscopy
Design and Development of Optical System for Portable Raman Spectrometer
An Yan, Liu Ying, Sun Qiang, Li Chun, Liu Bing, and Jiang Chengzhi
Aiming at miniaturization, high resolution and weak-signal detection of portable Raman spectrometer, the rational optical systems of the high-resolution grating spectrometer and the optical probe system with large object space numerical aperture (NA) are designed, and the testing of the performance of the prototype RamAiming at miniaturization, high resolution and weak-signal detection of portable Raman spectrometer, the rational optical systems of the high-resolution grating spectrometer and the optical probe system with large object space numerical aperture (NA) are designed, and the testing of the performance of the prototype Raman spectrometer is completed. According to the aberration theory of the Czerny-Turner(C-T) grating spectrometer, under the coma-free condition, the relation between the imaging plane and the system parameters of the grating spectrometer is established, which ensures the perfect match between the size of the image plane of the system and the size of the linear-array CCD, and then the design of the new coma-free C-T grating spectrometer is completed. By use of the telephoto optical structure of the “thick doublet”, the compact optical probe system with object NA of 0.33 is designed which perfectly matches with the entrance pupil of the grating spectrometer. The results of the spectral resolution are better than 0.6 nm and the Raman spectrum ranges from 781 nm to 1014 nm, with the prototype size of 243 mm×25 mm×71 mm. The five characteristic peaks of Raman spectrum of CCL4 are successfully measured by the prototype Raman spectrometer, which verifies the feasibility and the rationality of the optical design of the whole Raman spectrometer system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 330001 (2013)
Quantitative Analysis of Laser-Induced Breakdown Spectroscopy of Heavy Metals in Water Based on Support-Vector-Machine Regression
Wang Chunlong, Liu Jianguo, Zhao Nanjing, Ma Mingjun, Wang Yin, Hu Li, Zhang Dahai, Yu Yang, Meng Deshuo, Zhang Wei, Liu Jing, Zhang Yujun, and Liu Wenqing
The quantitative analysis model of laser-induced breakdown spectroscopy with adaptive kernel is established. Effect of ambient noise and energy jitter in measured density of heavy metals is gradually removed by Lorentz fitting and carbon normalization, and the intensity of plasmas is enhanced by graphite enrichment. QuThe quantitative analysis model of laser-induced breakdown spectroscopy with adaptive kernel is established. Effect of ambient noise and energy jitter in measured density of heavy metals is gradually removed by Lorentz fitting and carbon normalization, and the intensity of plasmas is enhanced by graphite enrichment. Quantitative analysis of laser-induced breakdown spectroscopy based on regression intelligent algorithm of support vector machine is achieved. The average relative standard deviations of lead and copper are 6.4361% and 6.9291%, and the maximum standard deviations are 9.1009% and 8.9280%.The average relative errors of lead and copper are 1.6765% and 1.2478 %, and the maximum relative errors are 5.5759% and 4.2604%. The correlation coefficients of lead and copper are 0.9979 and 0.9997. Methods and reference data are provided for the further study of fast measurement of trace heavy metals in water by laser-induced breakdown spectroscopy..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 330002 (2013)
Phase Error Correction of Spatial Heterodyne Spectrometer
Shi Hailiang, Xiong Wei, Li Zhiwei, and Luo Haiyan
Aiming at the characteristics of novel spatial heterodyne spectroscopy (SHS), the phase error mechanism is studied, and the actual phase of each wavelength is calculated using tunable lasers and the theoretical phase is acquired by frequency calibration, and the phase error is eliminated according to convolution in theAiming at the characteristics of novel spatial heterodyne spectroscopy (SHS), the phase error mechanism is studied, and the actual phase of each wavelength is calculated using tunable lasers and the theoretical phase is acquired by frequency calibration, and the phase error is eliminated according to convolution in the frequency domain. Using measured interferogram of continuous light source by spectrometer and atmospheric absorption of CO2 interferogram, a phase error correction experiment is carried out. The experiment, correcting the phase error of continuous light source and atmospheric absorption of CO2 interferogram measured by spatial heterodyne spectrometer, shows that the phase error correction algorithm can achieve perfect result for spatial heterodyne spectrometer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 330003 (2013)
Design of Visible-Ultraviolet Cylinder Mirror Imaging Spectrometer
Tang Yi, Zhang Zhige, Cheng Ting′ai, Nan Yibing, Huang Heqing, and Ni Guoqiang
By adjusting the difference of spectrometer focal power in tangential plane and sagittal plane with cylinder mirror, the astigmatism of the spectrometer is corrected. The sphere aberration and the coma of Czerny-Turner spectrometer is also analyzed. The sphere aberration is controlled by the F number of the optical sysBy adjusting the difference of spectrometer focal power in tangential plane and sagittal plane with cylinder mirror, the astigmatism of the spectrometer is corrected. The sphere aberration and the coma of Czerny-Turner spectrometer is also analyzed. The sphere aberration is controlled by the F number of the optical system. The coma is corrected by adjusting off-axis angles of the collimation mirror and the focus mirror. A prototype of wide band cylinder mirror imaging spectrometer is developed using imaging spectrometer tolerance analysis method based on Monto-Carlo simulation. The prototype works in 200～700 nm, and its aberrations are also corrected in such wide band. The spatial resolution in slit direction is 320 pixel. The focal length of the prototype f′=100 mm and its F number is 5.2. The spectral resolution in whole band is smaller than 2 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 330004 (2013)
Thin Films
Determination of Optical Constants of Rough Hydrogenated Amorphous Silicon Thin Films
Ding Wenge, Lu Yunxia, Ma Denghao, Yuan Jing, Hou Yubin, Yu Wei, and Fu Guangsheng
The transmission and reflection spectra of the rough thin films are directly affected by the surface roughness. If this effect is not taken into account, there will be evident error for the calculation of thickness and optical constants of rough thin films. Using the scalar wave scattering theory, the light scattering The transmission and reflection spectra of the rough thin films are directly affected by the surface roughness. If this effect is not taken into account, there will be evident error for the calculation of thickness and optical constants of rough thin films. Using the scalar wave scattering theory, the light scattering caused by rough film surface is analyzed in detail by introducing the surface root mean square roughness, and the transmittance expression of the thin film system is obtained. On this basis, the calculated film thickness and transmission spectrum are in agreement with the measurement results of the prepared hydrogenated amorphous silicon (a-SiH) thin film. The determined optical constants are closer to the actual ones. Because the calculation process is not based on the minimum value optimization algorithm and does not need the aid of complicated software, it is an effective and exact method to determine the thickness and optical constants of rough thin films..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 331001 (2013)
Study and Fabrication of Visible and Infrared Broadband Antireflection Coating
Fu Xiuhua, Sun Yingjie, Liu Dongmei, Zhang Jing, and Lin Jing
In order to meet the modern military comprehensive optical instruments′ operating requirements of one-machine multi-purpose, super broadband antireflection coatings with wavelength from 500 nm to 1200 nm are studied and fabricated. The broadband antireflection coatings are fabricated using mixed material H4, SiO2 and MIn order to meet the modern military comprehensive optical instruments′ operating requirements of one-machine multi-purpose, super broadband antireflection coatings with wavelength from 500 nm to 1200 nm are studied and fabricated. The broadband antireflection coatings are fabricated using mixed material H4, SiO2 and MgF2. The error causes are analyzed through experiments, and the result is simulated and optimized by variable metric method with the help of coating design software. By changing the master tooling of each layer in the process of fabrication, the effect of thickness error on the spectral properties is eliminated. Finally, the film is deposited by home-made vacuum coater, and the average reflectivity of the film is below 0.5% over the wavelength range from 500 nm to 1200 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 331002 (2013)
Influence of Plasma Scalds on Laser-Beam Distortion for 1064 nm High-Reflectivity Laser Film Surface
Chen Weixiao, Li Dawei, Liu Xiaofeng, Liu Wenwen, Fang Zhou, and Zhang Lei
Plasma scalds will be induced in the 1064 nm high reflectivity thin film during laser preconditioning, and they will modulate the laser beam which irradiates the scalds area, leading to laser beam distortion. Energy distribution of 1064 nm continuous laser which irradiates the scalds area is tested, and the reason of mPlasma scalds will be induced in the 1064 nm high reflectivity thin film during laser preconditioning, and they will modulate the laser beam which irradiates the scalds area, leading to laser beam distortion. Energy distribution of 1064 nm continuous laser which irradiates the scalds area is tested, and the reason of modulation and its expression in different laser propagation distance is analysed, both of which provides basis for the functional damage evaluaiton and reasonable use of laser-conditioned sample. The result of the experiment indicates that the pit in the center of scalds may strengthen the peak intensity of beam with annular fringes, and the maximum energy contrast and modulation degree between un-modulated laser beam and modulated laser beam becomes smaller with the laser propagation distance increasing, which means the phenomenon of laser modulation caused by plasma scalds becomes weak with the increasing propagation distance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 3, 331003 (2013)
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