Contents
2015
Volume: 35 Issue 9
52 Article(s)
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Atmospheric Optics and Oceanic Optics
Simulation of Multi-Angle Polarized Reflectance of Haze
Wang Zhongting, Chen Liangfu, Li Qing, Li Shenshen, Shang Huazhe, and Chen Hui
Based on optical properties of aerosols and clouds (OPAC) and ground- based measurements,four typical haze components included water soluble (WASO),soot (BC),dust (DUST) and sub- micron (SubM)components.By Mie theory,their extinction,scattering phase function,polarized phase function are calculated,and for water solublBased on optical properties of aerosols and clouds (OPAC) and ground- based measurements,four typical haze components included water soluble (WASO),soot (BC),dust (DUST) and sub- micron (SubM)components.By Mie theory,their extinction,scattering phase function,polarized phase function are calculated,and for water soluble particle,these parameters are calculated in different relative humidities(RHs).Then,multi- angle intensity and polarized signals,which are received by the satellite,are simulated for these haze components by RT3 (radiative transfer 3).The results show that scalar signal intensities of WASO and SubM are larger than others in most satelite observation angles,while polarized signal intensities of BC and WASO are obviously larger than the others.As the increasing of RH,the extinction of WASO will increase while scattering and polarized phase function will decrease entirely,and the main reason is the hygroscopic growth of particle radius.So,for remote sensing inversion of haze,multi-angle polarized measurements will be assisted by multi-angle intensity measurements..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 901002 (2015)
Analysis of Factors Affecting the Data Accuracy of Doppler Wind Lidar
Wang Guocheng, Sun Dongsong, Duan Lianfei, and Shu Zhifeng
The fundamental working theory of the Doppler wind lidar (DWL) based on Fabry-Perot (F-P) etalon is introduced.The typical detection data of DWL system is provided.The factors depressing DWL wind detection accuracy are analyzed,including background light intensity,operation state of detector,the locking state of laser The fundamental working theory of the Doppler wind lidar (DWL) based on Fabry-Perot (F-P) etalon is introduced.The typical detection data of DWL system is provided.The factors depressing DWL wind detection accuracy are analyzed,including background light intensity,operation state of detector,the locking state of laser frequency,the environment of seed laser,deformation of the receiver caused by sudden changes of the workplace temperature,and so on.Strong background light will cause the system signal-to-noise ratio decreases rapidly.Saturated detectors will be in nonlinear working state and generate invalid data.The lose lock on laser will cause wind profile to move parallel,the instability of seed laser environment temperature will cause the laser jump phenomenon.After overcoming the factors one by one,the wind speed variation of DWL with balloons is within 1.4 m/s,wind direction deviation is within 2.2°..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 901003 (2015)
A New Atmospheric Refraction Correction Method of Star Sensor
Jiao Hongwei, Pan Liang, and Zhang Tongshuang
In order to simplify the atmospheric refraction correction process and improve the independent attitude measurement capability of star sensor,a new atmospheric refraction correction method based on reference quantity correction is proposed.The proposed method is simple in star apparent zenith distance calculation and iIn order to simplify the atmospheric refraction correction process and improve the independent attitude measurement capability of star sensor,a new atmospheric refraction correction method based on reference quantity correction is proposed.The proposed method is simple in star apparent zenith distance calculation and it does not require the information of carrier attitude.The refraction correction doesn′ t need to solve the dual nonlinear equations,it only needs simple addition.Simulation and experimental results show that the results of attitude estimation using the reference quantity refraction correction method and are consistent with those of the observed quantity refraction correction method,and the relative error between them is within 0.1 arc seconds.For star sensor attitude measuring application,the proposed refraction correction method does not need external posture information.It is simple and has no loss of attitude measuring precision..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 901004 (2015)
Propagation Characteristics of Spectral Degrees of Cross-Polarization of Quasi-Homogenous Beams
Chen Feinan, Qi Jun, Chen Jingjing, Chen Yanru, Guo Fengxia, and Li Yan
The propagation characteristics of spectral degrees of cross-polarization (SDCP) of quasi-homogenous(QH) beams are studied based on the unified theory of coherence polarization and generalized Huygens-Fresnel principle.The characteristics of SDCP changing with propagation distance of different points in the field are oThe propagation characteristics of spectral degrees of cross-polarization (SDCP) of quasi-homogenous(QH) beams are studied based on the unified theory of coherence polarization and generalized Huygens-Fresnel principle.The characteristics of SDCP changing with propagation distance of different points in the field are obtained.The results show that the quasi- homogenous sources which have same changes of the degree of polarization（DOP）of each position point may have different changes of SDCP between two spatial points.They may increase or decrease with propagation distance increases depend on the distance of two position points due to the perturbations of turbulence,it will have the same value in a special distance,and then will deviate from each other when propagation distance increases continuously.The degree of coherence and the correlation of intensity fluctuations have different characteristics of variations.The results obtained reveal close relationship between high order statistic properties of optical beam field.The physical significance of SDCP will be the foundation of applications like correlation imaging and polarization communications in free space or atmosphere..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 901005 (2015)
Simulation Analysis and Design of a Dynamic Refocus System for Laser Guide Star
Shao Lina, Cao Zhaoliang, Mu Quanquan, Hu Lifa, Zhao Jingli, Zhang Hongsheng, and Xuan Li
By increasing the sample scattering layer thickness of laser guide star,the detection energy of wavefront sensor is enhanced but makes the detection spot diffused.To solve this problem,a dynamic focus system is designed.Influence of the sample thickness on the wave-front detection energy is analyzed and result shows thBy increasing the sample scattering layer thickness of laser guide star,the detection energy of wavefront sensor is enhanced but makes the detection spot diffused.To solve this problem,a dynamic focus system is designed.Influence of the sample thickness on the wave-front detection energy is analyzed and result shows that the wave-front detection energy increases nonlinearly with the sample thickness.When the sample thickness is 4 km with the laser pulse energy of 10 mJ,the number of received photons is 120 per sub-aperture of telescope,which meets the detection requirements.Then effect of diffusion spot on wave-front detection accuracy is analyzed,the result shows that the wave-front measurement error is about 0.5 λ when the sample thickness is 4 km,which leads accurate detection unfeasible.In order to achieve accurate detection,dynamic focus system is designed based on the analysis results,moving distance of the focusing mirror is reduced from 111 mm to 100 μm,and moving speed from 4200 m/s to 3.8 m/s,which meet the application requirements.Zemax softwave optimized results show that the optical system can achieve the ideal imaging for 4km sample thickness range..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 901006 (2015)
Observational Study of Aerosol Distribution overJing-Jin-Ji Area Using Airborne Lidar
Bo Guangyu, Xie Chenbo, Wang Bangxin, Wu Decheng, and Zhong Zhiqing
An airborne two-wavelength polarization Mie lidar is designed for detecting three-dimensional (3-D) distributions of atmospheric aerosols at Jing-Jin-Ji area. One typical field campaign is described. The flight path is perpendicular to the airstreams, which makes it ideal for observation of aerosol 3-D structure on theAn airborne two-wavelength polarization Mie lidar is designed for detecting three-dimensional (3-D) distributions of atmospheric aerosols at Jing-Jin-Ji area. One typical field campaign is described. The flight path is perpendicular to the airstreams, which makes it ideal for observation of aerosol 3-D structure on the flight path. The observation result of the aerosol distribution during the flight shows that regional three- dimensional air pollution has formed around Jing-Jin-Ji area, due to densely pollutant source and air-flow diffusion. The diffusion process of the aerosol emission from one typical heavy pollution source is given using the aerosol distribution data around it. The preliminary result shows that this airborne lidar provides a unique airborne remote sensing platform for monitoring the aerosol distribution over a wide region..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 901007 (2015)
Remote Sensing of Suspended Particle Size in Yellow Sea and Bohai Sea
Chen Yahui, Qiu Zhongfeng, Sun Deyong, Wang Shengqiang, and He Yijun
Suspended particle size is an important marine optical parameter. In Yellow Sea and Bohai Sea, suspended particle size plays an important role in marine biogeochemical processes and ocean color remote sensing, since a large quantity of sediments dominate water composition in this study area. Using 47 in situ samples coSuspended particle size is an important marine optical parameter. In Yellow Sea and Bohai Sea, suspended particle size plays an important role in marine biogeochemical processes and ocean color remote sensing, since a large quantity of sediments dominate water composition in this study area. Using 47 in situ samples collected in May and November 2014, based on Geostationary Ocean Color Imager (GOCI) band, a novel inversion model is developed to estimate the median diameter (D50) of suspended particle sizes, by means of remote sensing reflectance (Rrs). The obtained results indicate that a power model by Rrs(555 nm) performs best, coefficient of determination R2 is 0.72, mean absolute percentage error SMAPE is 6.35%. As for model validation, the root mean square error (SRMSE) by using the independent dataset shows a value of about 0.17, and the relative errors ranged from -5% to 5%. The robustness of the developed models is investigated by introducing 5% random error into original data, and the corresponding results show that SMAPE is below 2%, and SRMSE is less than 0.002. Additionally, the model is successfully applied to derive distribution map of D50 from GOCI data (Jun, 2013), and the results show that the diameters of suspended particles increas from near-shore region to off-shore waters..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 901008 (2015)
Fiber Optics and Optical Communications
Preparation of All-Fiber HC-PCF Low-Pressure Gas Cell by the He-Assisted Fusion Splicing Technique
Hao Jun, Liu Ye, Li Wencai, Chen Dijun, Feng Sujuan, Cai Haiwen, and Mao Qinghe
A method of He-assisted fusion splicing is demonstrated to prepare the all-fiber hollow-core photonic crystal fiber (HC-PCF) low-pressure gas cell.In the preparing process,the high gas purity is guaranteed by flushing the HC-PCF with the high-pressure desired gas;the dynamical gas flow in the HC-PCF is studied with a sA method of He-assisted fusion splicing is demonstrated to prepare the all-fiber hollow-core photonic crystal fiber (HC-PCF) low-pressure gas cell.In the preparing process,the high gas purity is guaranteed by flushing the HC-PCF with the high-pressure desired gas;the dynamical gas flow in the HC-PCF is studied with a self-made real-time spectral detection system;and a 10 m all-fiber HC-PCF low-pressure CO2 gas cell with the pressure of 70 kPa and insertion loss less than 2 dB is successfully prepared by He-assisted fusion splicing technique.This method may also be suitable for the fabrication of HC-PCF gas cell with lower pressure,and the prepared gas cell shows good air-tightness and long-term stability..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 906001 (2015)
Preparation and Spectrum Measurement of PbSe Quantum-Dot Doped Fiber with a Solid Fiber Core of UV Gel
Cheng Cheng, and Shao Wei
PbSe quantum dot (QD,in 4.4-nm diameter) doped fibers are prepared with a solid fiber core of UV gel,in doping concentration from 0.1 mg/mL to 6.0 mg/mL,and with different fiber lengths.By measuring the absorption spectra of QD doped fibers,the absorption cross-section of 980 nm varying with the doping concentration anPbSe quantum dot (QD,in 4.4-nm diameter) doped fibers are prepared with a solid fiber core of UV gel,in doping concentration from 0.1 mg/mL to 6.0 mg/mL,and with different fiber lengths.By measuring the absorption spectra of QD doped fibers,the absorption cross-section of 980 nm varying with the doping concentration and the fiber length is determined.Measuring photoluminescence (PL) spectra of the doped fibers show that the PL-peak intensity varies with both the doping concentration and fiber length.Thus,there is an advisable doping concentration and fiber length corresponding to the maximum PL intensity.The results presented in this paper provide a support for development of PbSe-QD doped fiber amplifiers and lasers in the future..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 906002 (2015)
Research on Hollow Fiber Raman Detection System for Edible and Fried Oils
Wang Wei, Chen Pan, Liu Binghong, Tang Xiaoli, Zhu Xiaosong, and Shi Yiwei
Based on the detection of edible oil,a Raman spectrum detection system using the hollow fiber with silver plated in the inner surface as the sensor cavity is established for detecting edible and fried oils.A mathematical model is proposed to describe Raman signal intensity.The fiber length is optimized by simulation reBased on the detection of edible oil,a Raman spectrum detection system using the hollow fiber with silver plated in the inner surface as the sensor cavity is established for detecting edible and fried oils.A mathematical model is proposed to describe Raman signal intensity.The fiber length is optimized by simulation results and experimental data.After system establishment and optimization,samples of oil are measured by the system,including:fried oils collecting from two food stands and several kinds of edible oils.Ratio of Raman peak intensities at 3005 cm-1 and 2897 cm-1 is proposed to describe the degree of oil un-saturation.The un-saturation collecting experiment for the soybean oil used shows that un-saturation degree is inversely proportional to frying time.A smart and efficient detection system is provided to analyze oil structures and estimate oil un-saturation,where Raman spectrum characteristic peak is clear and sharp.It has shown potentiality in food safety detecting field..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 906003 (2015)
Spectral Shape Multiplexing Techology of Fiber Bragg Gratings Using Simulated Annealing Algorithm
Qi Yuefeng, Li Cailing, Jiang Peng, Wang Lu, Zhang Jinghao, and Wang Wei
The spectral shape multiplexing technology and the simulated annealing algorithm are used to theoretically analyze and experimentally study on the spectral overlap of fiber Bragg gratings(FBGs).When the spectra of FBGs are fully or partially overlapped,the recognition of 2,3 and 4 gratings multiplexing is discussed.In The spectral shape multiplexing technology and the simulated annealing algorithm are used to theoretically analyze and experimentally study on the spectral overlap of fiber Bragg gratings(FBGs).When the spectra of FBGs are fully or partially overlapped,the recognition of 2,3 and 4 gratings multiplexing is discussed.In this research,no more than 4 spectra overlapped gratings are well distinguished and their recognition accuracies are within 10 pm,which are in agreement with the theory.The method provides an alternative solution for the multiplexing demodulation of fiber grating sensing network in large scale..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 906004 (2015)
Research on Refractive Index Changes of Fiber Bragg Grating Induced by Multiple Post-Exposure
Bi Weihong, Jiang Peng, Wu Yang, Liu Qiang, Qi Yuefeng, Fu Xinghu, and Fu Guangwei
Refractive index changes of hydrogen loaded fiber Bragg grating induced by multiple post-exposure are researched.Changes of fiber grating refractive index induced by multiple post-exposure are analyzed based on the two-step process photosensitive model.The relationship between grating refractive index and multiple postRefractive index changes of hydrogen loaded fiber Bragg grating induced by multiple post-exposure are researched.Changes of fiber grating refractive index induced by multiple post-exposure are analyzed based on the two-step process photosensitive model.The relationship between grating refractive index and multiple postexposure is obtained under different initial refractive index distribution,and the mathematical models about mean refractive index and modulation refractive index of fiber grating are built up.Furthermore,variation characteristics of fiber Bragg grating wavelength and refractive index under multiple post-exposure are experimentally studied using 193 nm UV laser.The results show that,under multiple post-exposure,the grating wavelength gets red shifted and the shift quantity is related to post-exposure conditions.The grating refractive index increases firstly and then tends to be stable.The growth rate is related to post-exposure conditions and the maximum value is determined by the initial refractive index distribution of fiber Bragg grating..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 906005 (2015)
Filtering Analysis on the Random Noise of Fiber Optic Guroscope
Tian Yunpeng, Yang Xiaojun, Guo Yunzeng, and Liu Feng
The datum axis of high precision photoelectric steady tracking platform jittering and drifting slowly often makes the output signal of fiber optic gyroscope (FOG) contain random noise.Based on the characteristics mentioned above,time series analysis of the data actually measured from FOG which is actually applied in enThe datum axis of high precision photoelectric steady tracking platform jittering and drifting slowly often makes the output signal of fiber optic gyroscope (FOG) contain random noise.Based on the characteristics mentioned above,time series analysis of the data actually measured from FOG which is actually applied in engineering is conducted.Noise model is established by using the recursive least squares method,and it is processed with adaptive Kalman filter.With an exhaustive analysis by using the Allan variance method,it is shown that the filtering effect of Kalman algorithm that simply adapts the observation noise covariance matrix R is much better than that of normal Kalman algorithm,and the real-time performance is better than that of the Saga-Huga adaptive Kalman algorithm.For the Kalman algorithm,the amount of calculation added is small.This work has some practical value to improve the performance of photoelectric stable tracking platform..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 906006 (2015)
Phase-Matching Characteristic of Photonic Crystal Fiber with Three Zero-Dispersion Wavelengths
Zhao Xingtao, Liu Xiaoxu, Wang Shutao, Liu Zhaolun, Wang Wei, Li Shuguang, and Hou Lantian
The dispersion characteristics of photonic crystal fibers are calculated by multipole method.Single mode fibers with three zero-dispersion wavelengths are obtained by the accuracy design of the fiber structure parameters.Closing to zero and flattened dispersion can be obtained in the fibers with three zero-dispersion wThe dispersion characteristics of photonic crystal fibers are calculated by multipole method.Single mode fibers with three zero-dispersion wavelengths are obtained by the accuracy design of the fiber structure parameters.Closing to zero and flattened dispersion can be obtained in the fibers with three zero-dispersion wavelengths.The special phase-matching characteristics of the fibers with three zero-dispersion wavelengths are analyzed.The variation of phase-matching wavelength with the pump wavelength and the pump power is obtained for the different fiber structure parameters.The characteristics of phase-matching wavelength for different dispersion curves are analyzed.The presence of three zero-dispersion wavelengths can realize the high efficiency wavelength conversion of optical soliton between two anomalous dispersion regions,get six new four- wave mixing phase- matching wavelengths and produce more photon pairs.These provide a new physical condition for efficient multiple wavelength four-wave mixing and supercontinuum spectrum research..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 906007 (2015)
Invisible Information Casting System Based on Visible Light Communication
Zhu Huanyu, and Zhu Yijun
An invisible information casting system based on visible light communication (VLC) is proposed.Invisible information is embedded in normal displayed images which can be captured by imaging devices and recovered by corresponding decoding algorithms under the premise of displaying original images and videos normally.TranAn invisible information casting system based on visible light communication (VLC) is proposed.Invisible information is embedded in normal displayed images which can be captured by imaging devices and recovered by corresponding decoding algorithms under the premise of displaying original images and videos normally.Transmitting advertisement information in the invisible way can avoid the harassment by mass media and realize directional advertisement to the target customers.The system is easy to be transplanted to many handheld devices like cell phones and pads.Finally,the system feasibility is verified and the main factors which affect the system performance are evaluated through experiments..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 906008 (2015)
Fourier Optics and Signal Processing
Beam Propagation Characteristics in Four-Cylindrical-Lens Slit Spatial Filter
Wan Jing, Xiong Han, Zhang Xiang, Zhuang Zhenwu, and Yuan Xiao
Based on the four-cylindrical-lens slit spatial filter proposed by American Lawrence Livermore National Laboratory, the beam propagation characteristics in the slit spatial filter has been studied with Rayleigh-Sommerfeld diffraction integral and commercial Matlab software on image relay and spatial filtering. Unlike tBased on the four-cylindrical-lens slit spatial filter proposed by American Lawrence Livermore National Laboratory, the beam propagation characteristics in the slit spatial filter has been studied with Rayleigh-Sommerfeld diffraction integral and commercial Matlab software on image relay and spatial filtering. Unlike the conventional pinhole spatial filter, the front (back) focal plane of the slit spatial filter system is not only related with focal length, but also with the distance between the cylindrical lenses, which is beneficial for greatly decreasing the focal intensity in high-power lasers by about 3 orders of magnitudes and greatly decreasing the scale of the spatial filter. However, with the slit spatial filter, negative point is also brought about that, the image relay of slit spatial filter can be strict satisfied only in the situation of 1 time beam expansion. In the situation of 1 times beam expansion, the spatial filtering of the slit spatial filter is consistent with the conventional pinhole spatial filter..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 907001 (2015)
Imaging Systems
Analysis and Comparison of Signal-to-Noise Ratio of Spatially Modulated Interference and Diffraction Grating Imaging Spectrometers
Jin Yangming, Wang Yan, Zhao Zhicheng, Chen Xinhua, Song Wenbao, and Shen Weimin
Sagnac spatially-modulated interference imaging spectrometer and Offner convex diffraction grating imaging spectrometer are focused on,and their signal- to- noise performance is seriously analyzed.Through derivation of the spectral radiance of their acquired image pixels under same observation condition,it is shown thaSagnac spatially-modulated interference imaging spectrometer and Offner convex diffraction grating imaging spectrometer are focused on,and their signal- to- noise performance is seriously analyzed.Through derivation of the spectral radiance of their acquired image pixels under same observation condition,it is shown that spatially-modulated interference imaging spectrometer no longer has high throughput and multiplex advantages so that its signal-to-noise is lower than diffraction grating imaging spectrometer.Further,the latter’s signal-tonoise ratio advantage becomes more significant as the increase of spectral band number..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 911001 (2015)
Applying Wavefront Coding Technology on Enhancing Robustness of Space Camera
An Ning, Zhang Binglong, Jin Jiangao, and Li Bo
In normal conditions, image quality of space camera optical system changes very little in a permissible range of depth of focus，which will appear different degrees of falling when the image plane is out of depth of focus however. The wavefront coding technology (WFC) can extend the depth of focus very well，and enable tIn normal conditions, image quality of space camera optical system changes very little in a permissible range of depth of focus，which will appear different degrees of falling when the image plane is out of depth of focus however. The wavefront coding technology (WFC) can extend the depth of focus very well，and enable the optical system to be insensitive to defocus. The user-defined merit function using modulation transfer function as image quality guideline is proposed based on extended polynomial to import cube phase distribution in the pupil, the optical system is designed of WFC system, and the test device is builded. The test results show that the image of WFC system is not only correspond to image of original system, but also keeps stably in a big range of depth of focus, which proves the big value of WFC on enhancing the stability of space camera..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 911002 (2015)
Image Distortions Caused by Rotational Double Prisms and Their Correction
Zhou Yuan, Fan Shisun, Liu Guangcan, Chen Ying, and Fan Dapeng
The image distortions caused by the prisms are investigated in rotational double prism scanning imaging and the inverse ray tracing is performed to correct the image distortions.To evaluate the characteristic and the extent of distortions,the rotation angles of prisms and the incident direction are obtained based on thThe image distortions caused by the prisms are investigated in rotational double prism scanning imaging and the inverse ray tracing is performed to correct the image distortions.To evaluate the characteristic and the extent of distortions,the rotation angles of prisms and the incident direction are obtained based on the direction of the line of sight and the size of the field of view.The rays from the field of view span are traced through the two prisms based on the vector form Snell’s law.The image deformations are modeled as case examples for the infrared images of germanium prism system and the visible images of glass prism system.The result shows that the images are compressed along the deflection direction from the system axis and the deformations become more prominent with increase in deviation angle.To correct the distorted images,the rays from the image points are traced inversely through the prisms.A scanning imaging system for the visible band,based on the rotational double prism,is built and its image distortions are analyzed.The results show that the simulation predictions for image distortions are correspond with the experimental observations.The inverse ray tracing can effectively correct the distortion and fairly improve the quality of the distorted images for both simulation images and experimental images.The analysis results about distortion and its correction method have referenced value on the imaging applications of rotational double prism..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 911003 (2015)
Instrumentation, Measurement and Metrology
Impact of Distance between Detector and LED on Measurement of Averaged LED Intensity
Liu Jian, Liu Hui, Zhao Weiqiang, and Zhang Baozhou
Commission International de Illumination (CIE) publishes‘CIE 127 technical report’(CIE 127) for light emitting diode(LED) measurement.Two different conditions (condition A and condition B) for measurement of averaged LED Intensityare proposed in CIE 127,and the LED measurement method gradually win the worldwide recogniCommission International de Illumination (CIE) publishes‘CIE 127 technical report’(CIE 127) for light emitting diode(LED) measurement.Two different conditions (condition A and condition B) for measurement of averaged LED Intensityare proposed in CIE 127,and the LED measurement method gradually win the worldwide recognition.Most of the LED has a different averaged LED intensity in these two measurement conditions,and the difference is up to 10% in some LED measurements,so it is difficult to evaluate the averaged LED intensity accurately.Mathematical models for different kinds of luminous intensity distribution have been created according to a large amount of measurement data.Simulation results and measurement results make clear that the impact of strong directional luminous intensity distribution can be reduced to less than 0.5% when distance between detector and LED is up to 645 mm,and the equivalent full plane angle is approximately 0.5°,this work makes the value of averaged LED intensity have consistency widely..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 912001 (2015)
Study on Nonlinearity Coefficient Measurement for Optical Detector Using Infrared LED
Zhao Weiqiang, Liu Hui, and Liu Jian
A simple and practical technique is studied to develop a near- infrared nonlinearity coefficient measurement for optical detector. Two infrared LEDs are used, and two source meters are adopted to control the LEDs and their driving currents. Using flux-addition method, the proposed method achieves the measurement of nonA simple and practical technique is studied to develop a near- infrared nonlinearity coefficient measurement for optical detector. Two infrared LEDs are used, and two source meters are adopted to control the LEDs and their driving currents. Using flux-addition method, the proposed method achieves the measurement of nonlinearity coefficient within four orders of magnitude at certain wavelength, which is determined by the emission peak of LED. The 940 nm LED is used as an example. The room temperature is controlled and the infrared LEDs as the light sources are quite stable. When the ignition time ranges from 1 min to 10 min, the relative standard deviation of the radiation flux is not greater than 0.022%. The reproducibility of the LED flux is also studied. The LED is turned on and off 10 times, and the relative standard deviation of the radiation flux does not exceed 0.044% at different flux levels. The measurement uncertainty is discussed and evaluated. The expanded measurement uncertainty of the calibration results is 0.07% (k=2)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 912002 (2015)
Main Aperture Area Measurement of the SIAR
Chen Xiangzi, Fang Wei, Yang Zhenling, Xia Zhiwei, and Wang Yupeng
For solar irradiance absolute radiometer (SIAR) boarded on meteorological satellites,the main aperture of known area plays an important role.The uncertainty of the main aperture area is at present one of the largest components of the uncertainty in SIAR measurement.The effective area method is a way to measure the mainFor solar irradiance absolute radiometer (SIAR) boarded on meteorological satellites,the main aperture of known area plays an important role.The uncertainty of the main aperture area is at present one of the largest components of the uncertainty in SIAR measurement.The effective area method is a way to measure the main aperture area.It defines the main aperture area based on the aperture of beam- limiting effect in radiometric measurement.Through a superposition of Gaussian beams to generate a known constant irradiance covers the surface of the measured apertures.The ratio of the flux to the irradiance gives the aperture area.We introduce the SIAR,and expound theoretical analysis of the measurement method using Matlab and TracePro software to make simulations.Put forward the specific measurement scheme,and make the uncertainty budget of the measurement device.The combined measurement uncertainty of the main aperture is about 8.2 × 10-5 .This method improves the measurement accuracy of the main aperture,makes the uncertainty of the irradiance measurement about the SIAR from 8 × 10-4 to 6.3 × 10-4 ..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 912003 (2015)
Analysis of Point-Diffraction Wavefront with Sub-Wavelength-Aperture Fiber
Chen Xixi, Wang Daodang, Xu Yangbo, Kong Ming, Guo Tiantai, Zhao Jun, and Zhu Baohua
Based on the fiber with sub- wavelength aperture,the point- diffraction wavefront with both high numerical aperture (NA) and high power is obtained,by which the poor light power of pinhole point diffraction wavefront and the small aperture angle of single-mode fiber point diffraction wavefront can be solved.We analyze Based on the fiber with sub- wavelength aperture,the point- diffraction wavefront with both high numerical aperture (NA) and high power is obtained,by which the poor light power of pinhole point diffraction wavefront and the small aperture angle of single-mode fiber point diffraction wavefront can be solved.We analyze the point- diffraction wavefront based on the finite difference time domain (FDTD) method,and the effects of various factors such as aperture,cone angle,film thickness of sub-wavelength-aperture fiber and NA on pointdiffraction wavefront error,aperture angle,light transmittance and intensity uniformity are discussed in detail.The simulation results show that an aperture angle about 90° and light transmittance about 29% can be obtained with 0.5 mm sub-wavelength fiber aperture,and the corresponding testing precision is better than root mean square value 0.0011 λ within 0.60 NA.The simulation demonstrates the feasibility of high NA and high power of point-diffraction wavefront,and provides theoretical basis for choosing the dimension of sub-wavelength-aperture fiber in practical system design..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 912004 (2015)
Lasers and Laser Optics
Multi-Point Laser Communication Optical Relay Antenna Servo System
Yu Xiaonan, Tong Shoufeng, Jiang Huilin, Zhang Lizhong, Dong Yan, and Bai Yangyang
Using the servo oscillating reflector antenna based on the rotating paraboloid principle,one- tomany laser communication network can capture,track and communicate with the laser signal coming from multipoint optical transceiver so as to form the space laser communication network.The basic principle,architecture,trackinUsing the servo oscillating reflector antenna based on the rotating paraboloid principle,one- tomany laser communication network can capture,track and communicate with the laser signal coming from multipoint optical transceiver so as to form the space laser communication network.The basic principle,architecture,tracking algorithm and the stitching technology of the servo antenna system are discussed.The rotating paraboloid principle is proved and the feasibility analysis of servo mirror antenna is given.It also introduces the closed-loop structure of tracking system and separately elaborates the component and index of the sensor,actuator,controller.Proportion integration differentiation (PID) algorithm with actuator limit,which is used for spot tracking,and debugging method are given.In order to achieve continuous tracking,the multi-reflector stitching technology is introduced,which mainly clarifies the implementation method of the reflectors.The whole servo antenna system is designed to test the perform range,tracking precision and stitching reliability.In the end,the qualification including 360° omnidirectional execution,tracking error less than 50 mrad and over 90% reliable stitching under indoor principle experiment can be achieved,which makes the laser communication network system operate normally ..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 914001 (2015)
Machine Vision
An Online Learning Visual Tracking Method Based On Compressive Sensing
Liu Wei, Zhao Wenjie, and Li Cheng
It is crucial to establish an effective online model for robust tracking. As existing online learning tracking algorithms do not judge whether the objective observation information is effective, a simple and efficient solution is proposed. The positive and negative samples are applied to build online object model, thenIt is crucial to establish an effective online model for robust tracking. As existing online learning tracking algorithms do not judge whether the objective observation information is effective, a simple and efficient solution is proposed. The positive and negative samples are applied to build online object model, then feature information is extracted from the multi-scale image feature space by compressive sensing to represent object, the random fern classifier is adopted to classify and determine the online update rate by a confidence measure strategy of features. The online object model will output the sample with the highest confidence, which is decided whether to update by an shelter feedback mecanism. Experimental results show that the proposed algorithm can complete the robust tracking under the condition of long-time occlusion, illumination changing, the video sequence of 320 pixel×240 pixel, the processing speed can keep 30~50 frame/s, which meets real-time application requirement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 915001 (2015)
Materials
Study on H2S Gas Sensor Based on Fluorescence Quenching of ZnS: Eu2+ Gas-Sensitive Film
Zhao Fen, Jiang Zhongwei, Feng Wenlin, Wang Ke, and Feng Xu
High quality ZnS: Eu2 + gas- sensitive materials have been synthesized by the ultrasound assisted hydrothermal/solvothermal method, and a gas sensor which contains ZnS: Eu2 + gas- sensitive film, simple chamber, miniature fiber optic spectrometer as well as the supporting software has been put forward. The gas sensor hHigh quality ZnS: Eu2 + gas- sensitive materials have been synthesized by the ultrasound assisted hydrothermal/solvothermal method, and a gas sensor which contains ZnS: Eu2 + gas- sensitive film, simple chamber, miniature fiber optic spectrometer as well as the supporting software has been put forward. The gas sensor has good stability and strong anti-jamming capability. It is found that the H2S gas concentration and the sensitive component′ s fluorescence quenching signal correspond to linear relationship via fluorescence quenching Stern- Volmer equation, which indicates that the gas sensor responds quickly and can be used for high sensitivity real-time online monitoring of H2S gas concentration..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 916001 (2015)
Numerical Simulations and Experimental Research on the Influence of Polarization Combination on Holographic Fabrication of Photonic Crystals
Qi Zhiming, and Liang Wenyao
Photonic crystals are novel artificial microstructures which are fabricated analogously to the arrangement of atoms in solid crystals.Laser holography method is an important method to fabricate photonic crystals where polarization combination of light beams plays a key role.Starting with the multi-beam interference priPhotonic crystals are novel artificial microstructures which are fabricated analogously to the arrangement of atoms in solid crystals.Laser holography method is an important method to fabricate photonic crystals where polarization combination of light beams plays a key role.Starting with the multi-beam interference principle,rhombic lattice is taken as an example to discuss its design principle and beam configuration.Moreover,combing with computer simulations,the influence of the combination of different types of polarizations is systematically studied,such as linear,circular and elliptical polarizations,on the "atom" of photonic crystal microstructures.It is found that different polarization combinations and intensity ratio of light beams sensitively affect the shape,direction,as well as the positions of the "atom".What is more,laser holography experiments are designed and carried out to verify the theoretical predictions and simulations.Real-time monitoring by computer is employed to facilitate the adjustment of polarizations and intensity ratio of light beams.Various photonic crystal microstructures are obtained under different conditions of polarization combinations and intensity ratios.The experimental results agree well with the theoretical predictions and simulations.The results are not only beneficial for improving the design efficiency of photonic crystals with specific shape of "atom",but also can effectively reduce the control blindness of polarizations and enhance the experimental efficiency accordingly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 916002 (2015)
Effect of Intermediate-Band on the ZnO/ZnTe Photovoltaic Solar Cell
Jiang Jianhui, Wu Kongping, Lu Kailin, Qi Jian, Peng Bo, and Zhu Yanna
In order to fully utilize the infrared photon energy in the solar radiation spectrum,the intermediate band solar cell as a efficient new concept solar cell is proposed.Group II-VI and III-V highly mismatched alloys are promising material systems in the application of high efficiency intermediate- band solar cell.SimulaIn order to fully utilize the infrared photon energy in the solar radiation spectrum,the intermediate band solar cell as a efficient new concept solar cell is proposed.Group II-VI and III-V highly mismatched alloys are promising material systems in the application of high efficiency intermediate- band solar cell.Simulated the performance parameters of ZnTe:O highly mismatched ternary alloys as intrinsic layer by using the solar cell capacitance simulator (SCAPS),and comparison with ZnO/ZnTe and ZnO/ZnTe/ZnTe.The result indicats that the existence of the intrinsic layer and material structure has a significant influence on the solar cell performance.While the ZnTe:O with intermediate-band as the intrinsic layer has better battery performance parameters than ZnO/ZnTe and ZnO/ZnTe/ZnTe.Different types of doping ZnTe:O intrinsic layer by changing the position of Fermi level in the intermediate-band affect the performance of solar cells.The simulation results show that when n-ZnTe:O is used as the intrinsic layer,the battery short circuit current density JSC and efficiency is 52.39 mA/cm2 and 61.58％ ,respectively,which are much higher than those of p-ZnTe:O solar cell..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 916003 (2015)
Study on Colour Fading and Optical Properties of Iceland Crystal
Wu Fuquan, Wu Wendi, Su Fufang, and Shi Meng
In order to understand the optical properties of the colored iceland crystals after fading by heat treatment, the fading conditions are explored by choosing the yellow and the purple crystals. One colored crystal is divided into two parts - the faded and the colored, and the two parts are polished. The optical propertiIn order to understand the optical properties of the colored iceland crystals after fading by heat treatment, the fading conditions are explored by choosing the yellow and the purple crystals. One colored crystal is divided into two parts - the faded and the colored, and the two parts are polished. The optical properties including transmittance, extinction ratio and principal refractive index are measured. The results indicate that the fading temperatures of yellow and purple iceland crystals are 405 ℃ and 485 ℃ respectively (constant temperature for 4 h). The extinction ratio and principal refractive index do not change after fading. The transmission spectra of the purple, dark yellow, light yellow crystals are extended to ultraviolet. Especially for the dark yellow crystal, the transmission range is extended to ultraviolet by about 130 nm, and the transmittance in 400~600 nm is greatly increased. After fading, the optical properties of colored iceland crystal achieve the optical performance of the natural clear crystal. Thus, the colour fading of iceland crystal has great significance for utilizing the scarce natural iceland crystals..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 916004 (2015)
Medical Optics and Biotechnology
Extracting Cardiac and Respiratory Features from Optical Signal of Functional Near-Infrared Spectroscopy
Pan Jinjin, Jiao Xuejun, Jiang Guohua, Jiao Dian, Jiang Jing, Zhang Zhen, Cao Yong, and Xu Fenggang
The rapid development of cognitive neuroscience makes objective determination of various physiological parameters possible. Functional near-infrared spectroscopy (fNIRS) is an emerging brain imaging tool that can detect human skin tissue hemodynamic indices including oxygenated hemoglobin (HbO), deoxygenated hemoglobinThe rapid development of cognitive neuroscience makes objective determination of various physiological parameters possible. Functional near-infrared spectroscopy (fNIRS) is an emerging brain imaging tool that can detect human skin tissue hemodynamic indices including oxygenated hemoglobin (HbO), deoxygenated hemoglobin (Hb) and total hemoglobin (tHb). Electrocardiograph (ECG) and respiration wave (RSP) are also two important physiological parameter determination methods. In order to obtain multiple physiological parameters using fNIRS only, three algorithms, including time-domain waveform characteristic analysis, frequency-domain band-pass filtering and wavelet decomposition and reconstruction, are used to calculate heart rate (HR) and breath rate (BR) based on the HbO data collected by fNIRS. The calculated HR and BR results are compared with the real HR (77.0199) surveyed by ECG and BR (22.9153) surveyed by RSP. The results show that the three methods can all extract HR from fNIRS effectively, wherein the band-pass filtering can extract the most accurate HR (76.8807) with the deviation of -0.1392. The BR (21.7039) with the deviation of -1.2114 is also calculated by the same algorithm. Extracting HR and BR features using fNIRS signal is realized..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 917001 (2015)
Nonlinear Optics
Propagation of Breathers in the Nematic Liquid Crystal Cell without Bias Voltage
Zhu Yeqing, and Hu Wei
The propagation of the (2+1)-dimensional breathers in a nematic liquid crystal (NLC) cell is theoretically investigated, whose tilt angle is fixed to π/4 in anywhere without bias voltage. The reponse function of beam′s propagation in such a special cell is obtained by the Green function which is based on a (2+1)-dimensThe propagation of the (2+1)-dimensional breathers in a nematic liquid crystal (NLC) cell is theoretically investigated, whose tilt angle is fixed to π/4 in anywhere without bias voltage. The reponse function of beam′s propagation in such a special cell is obtained by the Green function which is based on a (2+1)-dimensional nonlocal nonlinear Schro?dinger equation (NNLSE), and at the same time，the nonlinear coefficient in this case is obtained. The results show that the nonlinear effects can be stronger by certain technical means. On the balance point, the potential is approximate to the 2nd order, an approximate breather solution is presented. In addition, another breather solution is obtained by numerical integration. Respectively compared the breather amplitude fluctuations, period and the maximal (minimal) widths which are calculated by the two theoretical methods with the numerical simulations, it is obviously found that the results of numerical integration are more accurate..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 919001 (2015)
Optical Design and Fabrication
Precise Collimation Technology and Assembling Optical Modules in High Power Laser Facility
Liu Changchun, Cao Tingfen, Ye Haixian, Xu Xu, Chen Haiping, Luo Huan, Yuan Xiaodong, Xiong Zhao, Zhang Liang, and Yi Congzhi
SG-III power laser facility includes many large aperture optical modules, and it is a huge technical challenge to accomplish precise collimation of those units. A comprehensive error analysis methodology based on integrated light propagation theory, numerical calculation, engineering experience is proposed. Firstly, liSG-III power laser facility includes many large aperture optical modules, and it is a huge technical challenge to accomplish precise collimation of those units. A comprehensive error analysis methodology based on integrated light propagation theory, numerical calculation, engineering experience is proposed. Firstly, light transmission function with angle error in each mirror is built up, and the main influence factors are analyzed by means of error theory. Thus error decomposition in each light axis of optical module is employed in according with practical situation. Secondly, light axis materialization and homogeneous matrix transformation methods are utilized to depict the relationship of module, light axis, mirrors in one coordinate system，then the design of collimation stage is accomplished with the help of laser tracker. Finally, a assembling stage of typical module for collimation is set up and validated the proposed methodology which is extremely helpful to study the precise collimation technology in high power laser system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 922001 (2015)
Design of the Off-Axis Four Mirrors System by Differential Equations
Xia Chunqiu, Zhong Xing, and Jin Guang
With the improvement of requirements in resolution and system′s viewing about aerospace remote camera, off-axis four mirrors optical system has attracted more and more attention. Traditional design method in the off-axis system is gradually reaching its limitations. Therefore, a new design method based on differential With the improvement of requirements in resolution and system′s viewing about aerospace remote camera, off-axis four mirrors optical system has attracted more and more attention. Traditional design method in the off-axis system is gradually reaching its limitations. Therefore, a new design method based on differential equations is presented. Firstly, it introduces the principle and design idea of this design method by differential equations, and the restriction factor of the focal length, then an innovative coaxial four mirrors model is put forward. Finally, according to the differential equations method, a large field of view off-axis four mirrors optical system is designed, in which focal length is 100 mm, the field angle in sagittal direction is 40°, the field angle in meridian direction is 10°, the modulation transfer function (MTF) is above 0.606 at the 50 lp/mm. By experimental verification, the design method of differential equations is not only simple and effective in computation, but which also has a wide application prospect in the calculation of structure parameters of off-axis system and surface calculation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 922002 (2015)
A Light Emitting Diode Driver Based on Pulse Width Modulation and Pulse Amplitude Modulation Diming
Wu Yuxiang, Shang Jun, Wang Xiaohong, and Wen Shangsheng
Light emitting diode (LED) junction temperature variation,aging and other issues will lead to drift color temperature,color and other parameters.Current analog dimming and pulse width modulation (PWM) dimming can not solve this problem.Study found that average current affect flux,and peak currents affect color temperatLight emitting diode (LED) junction temperature variation,aging and other issues will lead to drift color temperature,color and other parameters.Current analog dimming and pulse width modulation (PWM) dimming can not solve this problem.Study found that average current affect flux,and peak currents affect color temperature.Therefore,a PWM and pulse amplitude modulation (PAM) dimming technology is proposed.Without changing the average value of the driving current pulse,we adjust the current pulse amplitude to compensate the color temperature drift.A PWM and PAM LED driver is shown,the experiment verifies that when average current is equal,luminous flux are equal,color temperature change along with peak current.Therefore,a PWM and PAM modulation technique proposed can compensate color temperature drift in actual dimming process,solve the problem of color temperature drift caused by LED junction temperature variation,aging and other problems..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 922003 (2015)
Assembly Error Analysis for Large Aperture Transport Mirror in High Power Solid-State Laser System
Wang Hui, Li Qin, Xiong Zhao, Yuan Xiaodong, Yao Chao, and Rong Yiming
Large aperture transport mirror is a typical unit in the high power solid- state laser system. Firstly, the principles of large aperture transport mirror′ s wavefront errors are discussed in detail, according to an analysis on its structure and assembly characters. Then, the fundamental mechanics model to evaluate the Large aperture transport mirror is a typical unit in the high power solid- state laser system. Firstly, the principles of large aperture transport mirror′ s wavefront errors are discussed in detail, according to an analysis on its structure and assembly characters. Then, the fundamental mechanics model to evaluate the surface deformation of mounted mirror is given. And furthermore, a technical framework combined with the methods of field optical measurements and 3D numerical modeling is proposed to predicate the surface profile of spatial installed mirror. The proposed method is verified with a case study. And some assembly problems in SG-III′s transport mirror are also discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 922004 (2015)
Numerical Calculation on Retro-Reflected Light Intensity of Cube Corners
Yuan Changying, Zhang Xiulu, Luo Fen, and Zhu Wenkun
In view of the importance of the relative reflective intensity on retroreflective coefficients estimation and new retroreflective material design,light transmission process in the cube corner elements is modeled,changes of light propagation and light vector polarization directions during reflection or refraction are trIn view of the importance of the relative reflective intensity on retroreflective coefficients estimation and new retroreflective material design,light transmission process in the cube corner elements is modeled,changes of light propagation and light vector polarization directions during reflection or refraction are traced,light intensity loss is calculated based on ray tracing principle.A numerical calculation program is set up for retroreflective light intensity calculations of cube corners under different incident angles,azimuth angles and polarization states.The reflected light relative intensities distributions at different incident angles and azimuth angles are computed with natural light illumination and polycarbonate as the body material.The results show that the reflected light intensity is significantly affected by the incident direction of light.For incident angles smaller than 25.5°,the reflected light relative intensities remain big and approximately constant value of 0.899.For incident angles bigger than 25.5°,the reflected light intensities decrease monotonically and are significantly influenced by azimuth angles..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 922005 (2015)
Optical Design of Frequency-Doubling System for Ultrashort Pulses Based on Prism Pairs
Zhang Liuyang, Sun Peijing, Huang Jinzhe, Qu Yuqiu, Pu Shaozhi, Wu Huinan, and Liu Yujiang
To realize frequency-doubling of ultrashort pulses,optical design software is employed to design the frequency-doubling system for 10 fs、0.8 μm ultrashort pulses in which contains four prisms,two lenses and a nonlinear crystal and all of them can be made by common glass materials.Firstly,the principle of frequencydoublTo realize frequency-doubling of ultrashort pulses,optical design software is employed to design the frequency-doubling system for 10 fs、0.8 μm ultrashort pulses in which contains four prisms,two lenses and a nonlinear crystal and all of them can be made by common glass materials.Firstly,the principle of frequencydoubling system is introduced.The optical system requires that all of frequency components can reach phase matching in nonlinear crystal and the merit function is built based on this point.The quality of the optical system is evaluated by permitted angle.Consequently,the optimization is executed for parts of fundamental wave and second harmonic wave.Size of prisms,distance between prism pairs and focus length of lenses which can make each frequency component in fundamental wave or second harmonic wave strike into nonlinear crystal in phasematching direction or superpose in space without spatial chirp are obtained.In addition,a macro program to compute group delay dispersion in optical system is used as an operand to control group delay dispersion in optical system.Finally,in order to reach optimal second harmonic generation,fundamental wave has no chirp at the center of crystal and the part second harmonic wave passes by introducing group delay dispersion to compensate the chirp in second harmonic wave.Then chirp in second harmonic pulse is eliminated and high quality second harmonic pulse output is obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 922006 (2015)
Optical Devices
An 360°Panoramic Imaging Design Method for Cylindrical Object
Wu Xiaojun, and Guo Yaxue
A new 360° panoramic imaging device is designed for cylindrical object inspection application. Through single viewpoint constraint, the shape of the reflective mirror is determined. According to the depth of field, resolution, field of view, etc. the parameters of the mirror are calculated. For a particular cylindA new 360° panoramic imaging device is designed for cylindrical object inspection application. Through single viewpoint constraint, the shape of the reflective mirror is determined. According to the depth of field, resolution, field of view, etc. the parameters of the mirror are calculated. For a particular cylinder size, the optimum mirror satisfies the camera depth of field constraints and the system resolution reaches 80% of the original camera resolution. The device is simulated by optical design software to determine the optimal parameters according to the evaluation criterion of image quality. The captured image from the proposed device is unwrapped through a systematic calibration method to obtain the perspective projection panoramas. The designed reflectance mirror is simple, low cost, low distortion and high imaging quality. The proposed 360° panoramic imaging mirror design method and corresponding device overcomes the traditional cylindrical object imaging hardware equipment complex, expensive shortcomings, and provides a design method for machine vision..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 923002 (2015)
Study on the Coupling Characteristics between Photonic Crystal Waveguide and Micro Resonator
Wu Liheng, and Wang Minghong
Coupling characteristics between photonic crystal waveguide and micro resonator have been studied by using coupled-mode theory,and then two types of symmetrical waveguides based on 5×5 micro resonator are designed in the two dimensional square-lattice photonic crystal.The transmission characteristics of the waveguCoupling characteristics between photonic crystal waveguide and micro resonator have been studied by using coupled-mode theory,and then two types of symmetrical waveguides based on 5×5 micro resonator are designed in the two dimensional square-lattice photonic crystal.The transmission characteristics of the waveguides are studied by the time domain finite difference method.The results show that different resonant coupling modes between waveguide and micro resonator are introduced by changing radius of the defect rod at the center of the resonator.Finally,nine pass bands are achieved.Both of the waveguides have the characteristics of narrow pass bands which shift towards lower frequency as radius of the defect rod increases.For the same resonator,the side coupling waveguide has lower output signal strength decay at central frequency than the directional coupling waveguide,and the side coupling waveguide has achieved more strength resonant coupling between waveguide and micro resonator.As signal processing interfaces,the two micro waveguides can be used to design narrow pass band filters,network interconnection devices,and they have applicable value in the fields of optical communications,integrated optical circuits,spectral sensors,etc..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 923003 (2015)
Research on Color Mixing Based on RGBW-LEDs
Song Pengcheng, Wen Shangsheng, and Chen Yingcong
A functional relationship between chromaticity coordinate and the duty cycle based on the RGBW color mixing equations and the pulse width modulation drive (PWM) is deduced. Multi-constraint optimization simulation of the luminous efficacy of source (LES) and color rendering index of the mixed-light is carried out on a A functional relationship between chromaticity coordinate and the duty cycle based on the RGBW color mixing equations and the pulse width modulation drive (PWM) is deduced. Multi-constraint optimization simulation of the luminous efficacy of source (LES) and color rendering index of the mixed-light is carried out on a Matlab program, which is further verified by the experiments. The results show that the RGBW light source can produce a wide range of color temperature from 2703 K to 7692 K. Under the highest Ra achievable, the Ra reaches 95, while the LES can reach 108 lm/W under the condition of an optimized LES. Furthermore, by reducing the color rendering index, the luminous efficiency improves significantly. The color rendering index likewise increases by reducing the luminous efficiency. By balancing these two factors, it has found that RGBW light source with high LES and Ra over 90 can best satisfy the demand of the current lighting manufacturing..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 923004 (2015)
Physical Optics
Generation of the Tunable Rectangular Hollow Beams by Using Wave Plates
Shi Jianzhen, Xu Shuwu, Ji Xianming, and Yin Jianping
A new scheme is proposed to generate adjustable rectangular hollow beams by wave plates. According to the birefringent property of crystals, the thickness distribution of wave plates is designed. The wave plates can form the four- step phase plate to o light and the π phase plate to e light. The rectangular cross- sectA new scheme is proposed to generate adjustable rectangular hollow beams by wave plates. According to the birefringent property of crystals, the thickness distribution of wave plates is designed. The wave plates can form the four- step phase plate to o light and the π phase plate to e light. The rectangular cross- section hollow beams will be obtained with the vertically irradiate on the surface of the wave plate by linearly polarized light beams. In addition, it is simple optical arrangement and easy adjustment to regulate the ratio of the length and the width of the adjustable rectangular hollow beams by means of the adjustment of the length and width of the light transmission windows. Approximate non- diffracted rectangular hollow beams will be obtained through the optical system consisting of the long focal length lens group and a conical surface prism focus diffracted light.‘Hollow bread’beams with the rectangular section will be obtained through the focusing of the high numerical aperture lens..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 926001 (2015)
Remote Sensing and Sensors
Small Target Detection in Hyperspectral Remote Sensing Image Based on Adaptive Parameter SVM
Wu Yiquan, Zhou Yang, and Long Yunlin
As for the problem of small target detection in hyperspectral remote sensing image, a detection method based on adaptive parameter support vector machine (SVM) is proposed. The low dimensional information of the hyperspectral image is obtained using the method of principal component analysis (PCA) and the redundancy ofAs for the problem of small target detection in hyperspectral remote sensing image, a detection method based on adaptive parameter support vector machine (SVM) is proposed. The low dimensional information of the hyperspectral image is obtained using the method of principal component analysis (PCA) and the redundancy of data is reduced. Then, small targets are positioned fast and roughly by an unsupervised detection method, and the posterior information of SVM is got by the position result. The kernel parameter of SVM is determined adaptively based on the posterior information and the criteria of divergence in the kernel space. The best hyperplane in the kernel space for the segmentation of targets and background is found by the SVM. Pixels are separated to targets and background by the best hyperplane. The accurate and stable target detection result is obtained by iteration. A large number of experimental results show that, compared to the existing methods such as RX method, kernel RX method and support vector data description (SVDD) method, the proposed method is more effective to detect small targets accurately in the hyperspectral remote sensing image..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 928001 (2015)
Reviews
Design of Collimating and Beam Expanding Laser System
Wang Peifang, Xiang Yang, Gao Jian, and Wang Jikai
Collimating and beam expanding laser system can be used in laser distance, laser cutting, space optics, laser interferometer and other fields. The main function of this system is aimed to reach the reqiurements of the system apreture though reducing the spatial divergence angles of the laser beam and then improving theCollimating and beam expanding laser system can be used in laser distance, laser cutting, space optics, laser interferometer and other fields. The main function of this system is aimed to reach the reqiurements of the system apreture though reducing the spatial divergence angles of the laser beam and then improving the beam collimation. Based on the priniple of non-focus zoom and with the help of analog of Zemax software, a collimating and beam expanding system is introduced: the wavelength of incident laser is 1064 nm; the value of divergence angle is less than 5 mrad; the diameter of incidence is 1 mm; the ratio of beam expanding is continually 4~24, which can help to reduce the beam divergence angle (the minimum angle is 0.208 mrad) and expand the spot size. With different ratios of the system, the root mean square (RMS) value of maximum wave aberration is 0.1769 λ (less than λ/4), which meets the requrements for image quality evaluation. The advantages of this system are simple, easily installed and ajusted, and also widely used in different projects..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 922007 (2015)
Spectroscopy
Measurement of Aerosol Optical Properties Using a Chernin Multipass Cell
Zhang Qilei, Xu Xuezhe, Zhao Weixiong, Cui Zhifeng, and Zhang Weijun
Using the Chernin multipass cell for measurement of aerosol extinction coefficient is reported. Within 38.4 m absorption optical path can realize detection sensitivity to 18 Mm - 1(5 s integrating time,and 30 times average). Combining a laboratory aerosol generation system, the extinction coefficients of 250 nm diameteUsing the Chernin multipass cell for measurement of aerosol extinction coefficient is reported. Within 38.4 m absorption optical path can realize detection sensitivity to 18 Mm - 1(5 s integrating time,and 30 times average). Combining a laboratory aerosol generation system, the extinction coefficients of 250 nm diameter monodispersed ammonium sulfate aerosol are measured under different particle concentrations. Three cross sections of 1.410 × 10-9，3.727 × 10-10，2.948 × 10-10 cm2 for ammonium sulfate aerosols at 300, 532, 532 nm is obtained, respectively. Error analysis carried out on the experimental results shows that this system can be used in the quantitative study of aerosol optical properties..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 930001 (2015)
High-Sensitivity Rapidly Swept Cavity Ringdown Spectroscopy for Monitoring Ambient CH4
Sun Liqin, Chen Bing, Kan Ruifeng, Li Mingxing, Yao Lu, Wei Min, and He Yabai
A rapidly-swept high-sensitivity cavity ringdown spectrometer (SC-CRDS) has been developed based on near-infrared continuous-wave diode lasers. By rapid sweeping/dithering of the ringdown cavity length via a piezo-electric transducer (PZT) , in combination with an automatic cavity length tracking circuit to follow laseA rapidly-swept high-sensitivity cavity ringdown spectrometer (SC-CRDS) has been developed based on near-infrared continuous-wave diode lasers. By rapid sweeping/dithering of the ringdown cavity length via a piezo-electric transducer (PZT) , in combination with an automatic cavity length tracking circuit to follow laser wavelength changes, fast CRDS measurements are achieved. This system is applied for measurement of CH4 concentration by detecting its spectroscopic absorption peak around 1653.73 nm (6046.95 cm- 1). By measuring multiple spectral points around the absorption peak, both the peak absorption value and corresponding laser wavelength are determined. A feedback control to the laser wavelength helps to stabilize its center wavelength to the absorption peak. Therefore, it successfully solves the problem of strong wavelength drift of the laser in free operation. The line strength of the CH4 1653.73 nm absorption feature is calibrated by measuring CH4 premixture samples with reference concentrations. This simple CRDS system shows stable and reliable performance as well as a CH4 concentration detection limit of 1.0×10-9; and it can be applied to monitor CH4 in ambient air over a long time..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 930002 (2015)
Optical Multipass Cell Based on Two Cylindrical Mirrors for High Sensitivity Detection of Methane
Chen Jiajin, Zhao Weixiong, Gao Xiaoming, and Zhang Weijun
The optical multipass cell has been widely used in the detection of absorption spectroscopy to increase the optical path length and improve the detection sensitivity. A multipass optical cell based on two cylindrical mirrors is described for application to tunable diode laser absorption spectroscopy. The multipass cellThe optical multipass cell has been widely used in the detection of absorption spectroscopy to increase the optical path length and improve the detection sensitivity. A multipass optical cell based on two cylindrical mirrors is described for application to tunable diode laser absorption spectroscopy. The multipass cell has the characteristics of simple and compact structure, high efficient use of mirror area, longer optical path length at the same base length compared with traditional multipass cells. Rotation of the cylindrical mirrors and variation in the cell base length have been used to achieve different spot patterns and path lengths. CH4 direct absorption measurement using the multipass cell with a fibre- coupled distributed- feedback laser at 1.653 μm has been performed. Detection sensitivity of 0.68 μmol/mol is realized for absorption optical path length of 13.8 m, and the detection of atmospheric CH4 has been achieved with the system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 930003 (2015)
Optical Design of Concave Grating Raman Spectrometer
Jin Xinghuan, Chen He, Dong Jianing, Chen Siying, Guo Pan, and Zhang Yinchao
Portable Raman spectrometer is designed with concave grating and spherical mirror on basis of classic Czerny-Turner spectrometer in this paper.The equation of primary coma-free is concluded according to aberration theory of concave grating.Combined with geometrical relationship in tangential plane,the relation of size Portable Raman spectrometer is designed with concave grating and spherical mirror on basis of classic Czerny-Turner spectrometer in this paper.The equation of primary coma-free is concluded according to aberration theory of concave grating.Combined with geometrical relationship in tangential plane,the relation of size of image plane and parameter of this system is concluded.Laser of 532 nm is selected asexcitation light source with object numerical aperture (NA) of 0.12.Charge-coupled device (CCD) with 1024 pixel×64 pixel is selected as detector,in which 64 pixels is combined to make a linear array CCD.This design is simulated and analyzed by Zemax,and spectral resolution of 0.3 nm is realized at the band from 537 nm to 615 nm with a portable institutions.Image plane is analyzed in Zemax non-sequential mode.The whole band is in the receiving range of CCD,which proves the feasibility of this structure..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 930004 (2015)
Comparative Study on Two Infrared Interferogram Acquisition and Spectrum Recovery Methods
Li Yan, Li Sheng, Gao Minguang, Xu Liang, Feng Mingchun, Ye Shubin, Liu Jianguo, and Li Xiangxian
The primary data sampling methods of Fourier transform infrared (FTIR) spectrometer include He-Ne laser triggering method and Brault method. The Brault method uses the hardware counter and the collected data has time delay, which may lead to the increase of subsequent data processing time. Therefore an improved data saThe primary data sampling methods of Fourier transform infrared (FTIR) spectrometer include He-Ne laser triggering method and Brault method. The Brault method uses the hardware counter and the collected data has time delay, which may lead to the increase of subsequent data processing time. Therefore an improved data sampling and processes method based on the Brault method is proposed. The method adopts the synchronous data acquisition card, and samples two-path data simultaneously, to get the precise zero crossing information of He- Ne laser with approximate similar triangle method. Interference signal is resampled according to the cubic spline interpolation method, and the software data sampling and processing is realized. In addition, the spectra obtained by the He-Ne laser triggering method and the proposed method are compared. The comparison results show that the background of H2O and CO2 absorption peaks in spectra obtained by the two methods are consistent with the standard absorption spectra, the improved data sampling and processing method based on the Brault method improves the signal-to-noise ratio of the spectrum, and the laser zero crossing information can get the stability of the moving mirror scanning speed. However, sampling and processing time for the He-Ne laser triggering method is less than that for the improved Brault method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 930005 (2015)
Thin Films
Investigations of Thin Film Design and Optimization Based on Clustering and Global Optimization Algorithm
Li Zizheng, Yang Haigui, Wang Xiaoyi, Wang Tongtong, Shen Zhenfeng, and Gao Jinsong
A new thin film design and optimization method based on clustering and global optimization algorithms is presented,which can iteratively change the initial structure.The design solution is calculated more thoroughly by this new design method than the traditional local optimization technique.When initial film structure A new thin film design and optimization method based on clustering and global optimization algorithms is presented,which can iteratively change the initial structure.The design solution is calculated more thoroughly by this new design method than the traditional local optimization technique.When initial film structure is far from the design target,this kind of clustering global optimization method has the unique advantage that a satisfied consequence can still be obtained.A practical thin film design task which is a broadband antireflection coating from the visible light to short- wave infrared is used to testify the ability and superiority of the clustering global optimization method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 931001 (2015)
Vision, Color, and Visual Optics
Halftone Spectral Prediction Model Based on Fuzzy Local Information C-Means Clustering Algorithm
Xu Junfei, Zhou Xiaofan, and Shi Yong
A spectral prediction model is proposed and applied to halftone print on paper substrate. The single dot of halftone print consists of several regions: core area of the dot has uniform thickness and the same thickness of ink-layer as that of the solid print. The edge regions have fuzzy thickness distribution function, A spectral prediction model is proposed and applied to halftone print on paper substrate. The single dot of halftone print consists of several regions: core area of the dot has uniform thickness and the same thickness of ink-layer as that of the solid print. The edge regions have fuzzy thickness distribution function, and the thickness of ink-layer is thinner than that of the solid print. The single dots of halftone print are clustered based on the density of pixel by the fuzzy local information C-means clustering algorithm, the well-bedded halftone dots can be achieved by the algorithm, and the fractional surface coverage of each cluster region can be calculated. A new algorithm model for halftone spectral prediction is established, and the spectral reflectivity predicted by the algorithm is well consisted with that measured through the halftone presswork proof, demonstrating that the prediction accuracy of the model is higher..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 933001 (2015)
X-Ray Optics
Design and Performance Testing of an Anti-Scattering Grid for Medium-Energy Flash Radiography
Liu Wenjie, Ma Qingpeng, Fan Cheng, and Liu Jun
An effective design of a tungsten anti-scattering grid with 2 mm in thickness for medium-energy X-ray imaging is proposed. The grid is produced by precise mechanical drilling technology and is with the typical size of 52 mm × 52 mm. The flash radiographic experiments to test grid anti-scattering performance are peAn effective design of a tungsten anti-scattering grid with 2 mm in thickness for medium-energy X-ray imaging is proposed. The grid is produced by precise mechanical drilling technology and is with the typical size of 52 mm × 52 mm. The flash radiographic experiments to test grid anti-scattering performance are performed based on a 450 kV medium-energy X-ray source, and the numerical simulation by the Monte Carlo method is also carried out. The imaging experimental results show that the image quality of flash radiography is improved substantially after the grid is used, and the boundary clarity in the sample core is enhanced obviously. The numerical simulation results indicate that scattering gray at any image position is lower than direct gray when the anti-scattering grid is used, and the ratio of scattering gray to direct gray is reduced by 74.7% compared to that without grids..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 934001 (2015)
Theoretical Prediction of Flat Circular-Channel MCP Performance for Focusing X-Rays
Zhao Dachun, Chen Bo, Liu Peng, and Zhang Hongji
Micro channel plate (MCP) used in X-ray focusing and imaging has such advantages as larger field of view, lower weight, and lower sensitivity to device alignment. Based on the X- ray total reflection theory, the focusing properties of flat circular-channel capillary arrays are discussed, and the theoretical calculationMicro channel plate (MCP) used in X-ray focusing and imaging has such advantages as larger field of view, lower weight, and lower sensitivity to device alignment. Based on the X- ray total reflection theory, the focusing properties of flat circular-channel capillary arrays are discussed, and the theoretical calculation of the relative gain and point spread function (PSF) on focal plane against the parameters of MCP is presented. The calculated results are verified via TracePro software, through which the focusing performance of MCP with 25 μm circular-channel diameter is simulated. Both of the model calculation and the simulation suggest that the relative gain of the MCP is nearly proportional to the source distance ls, while independent on the maximum aperture of the MCP. When the source distance is 110 mm, the relative gain can reach about 18. Furthermore, the performance of MCP with misalignment of off-axis and tilt is discussed, which suggests that the off-axis of MCP barely influence the focal spot while the tilts influence the location and shape of the spot..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 9, 934002 (2015)
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