Contents
2016
Volume: 36 Issue 5
42 Article(s)
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Atmospheric Optics and Oceanic Optics
Research on Simulating Atmospheric Optical Turbulence in Typical Area
Qing Chun, Wu Xiaoqing, Li Xuebin, Zhu Wenyue, Huang Yinbo, Rao Ruizhong, and Cai Jun
Based on the optical turbulence parameterization of Tatarski theory, the optical turbulence profiles of upper air at Gaomeigu, Maoming and Urumqi are simulated by numerical weather research and forecasting (WRF) model. Simulation results are compared with optical turbulence measured by micro-thermometer at Gaomeigu andBased on the optical turbulence parameterization of Tatarski theory, the optical turbulence profiles of upper air at Gaomeigu, Maoming and Urumqi are simulated by numerical weather research and forecasting (WRF) model. Simulation results are compared with optical turbulence measured by micro-thermometer at Gaomeigu and Maoming. It shows that the simulated and measured optical turbulence profiles are consistent well, and the correlation coefficient is up to 76%. The verified results at Gaomeigu and Maoming show that the method by using WRF model to simulate optical turbulence is feasible, and the optical turbulence profile of upper air at Urumqi is obtained. Combined with the climatic features of these three typical areas, characteristics and variation trend of upper air optical turbulence under different climate types are analyzed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 501001 (2016)
Detectors
Laser Ranging with Large Dynamic Range Based on Dual-Mode Detectors
Feng Baicheng, Li Zhaohui, Shi Yafan, Yan Peiqin, Du Bingcheng, Du Yanwei, Tan Tianle, Pan Haifeng, and Wu Guang
A new method of laser ranging is developed by employing a dual-mode photon detector to meet the large dynamic range of the echo photons. A single detector based on Si avalanche photodiode（APD）is operated between the linear mode and the Geiger mode by adjusting the bias voltage on APD and the detected dynamic range of tA new method of laser ranging is developed by employing a dual-mode photon detector to meet the large dynamic range of the echo photons. A single detector based on Si avalanche photodiode（APD）is operated between the linear mode and the Geiger mode by adjusting the bias voltage on APD and the detected dynamic range of the average photon number is 1~105 per pulse. The 30 m indoor and 500 m outdoor ranging experiments are carried out in the linear mode and the Geiger mode, respectively. The echo signal is recorded by a time correlated single photon counting equipment to investigate the ranging time characteristics in the dual-mode ranging system. The results indicate that the ranging system with a single detector can conveniently switch the operation mode to adapt to different ranging distances and environmental conditions and realize the large dynamic range detection. The measurement accuracy and the detection background noise are further studied while the operation modes are switched under different APD bias voltages..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 504001 (2016)
Diffraction and Gratings
Detection and Calculation of Mosaic Grating Error Based on Wavefront Method
Lu Yuxian, Qi Xiangdong, Mi Xiaotao, Jiang Shan, Yu Haili, Li Xiaotian, and Yin Lu
Mosaic grating is one of the most important methods for fabricating large-size plane diffraction gratings, and mosaic error is an important index to evaluate whether the mosaic grating can be used. Therefore, the real-time quantitative measurement of mosaic error can realize automatic closed-loop adjustment and improveMosaic grating is one of the most important methods for fabricating large-size plane diffraction gratings, and mosaic error is an important index to evaluate whether the mosaic grating can be used. Therefore, the real-time quantitative measurement of mosaic error can realize automatic closed-loop adjustment and improve the accuracy of mosaic grating fabrication. The mathematical model of the diffraction wavefront and the mosaic error of the grating is established and the mosaic error is analyzed. The diffraction wavefront of the mosaic grating at the zero-order and the negative first-order is extracted quantitatively by using a ZYGO interferometer. The numerical solution of five dimensional error is calculated by analyzing the mosaic error wavefront, and its accuracy is verified by the negative second-order diffraction wavefront. The experimental results show that the mosaic error of the gratings at the zero-order, the negative first-order and the negative second-order is consistent with each other, which provides theoretical guidance for measuring mosaic error by wavefront and realizing automatic closed-loop adjustment..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 505001 (2016)
Research on Temperature Tuning Properties of Chirped Fiber Grating
Zhang Xin, Yang Zhi, Li Qianglong, Li Feng, Yang Xiaojun, Wang Yishan, and Zhao Wei
According to the temperature tenability of chirped fiber grating, the minimum output pulse width can be obtained by controlling the fiber grating’s temperature to change the dispersion of the chirped fiber grating, and the feasibility of this idea is demonstrated through experiments. The chirped fiber grating is used aAccording to the temperature tenability of chirped fiber grating, the minimum output pulse width can be obtained by controlling the fiber grating’s temperature to change the dispersion of the chirped fiber grating, and the feasibility of this idea is demonstrated through experiments. The chirped fiber grating is used as the stretcher in the fiber chirped pulse amplification (CPA) system, and the gratings-pair is used as compressor. The positive dispersion brought by the stretcher is compensated by the negative dispersion provided by the compressor. The output pulse width is measured by the auto-correlation for denoting the dispersion of the chirped fiber Bragg grating indirectly as a function of temperature. It can be seen from the obtained experimental data that, when the temperature rises from -7 ℃ to 50 ℃, the pulse width falls from 1057 fs to 764 fs, and then rises to 910 fs, with a total change of 439 fs achieved. In the experiment, dispersion increases with temperature rising, changing from insufficient dispersion compensation to over dispersion compensation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 505002 (2016)
Fiber Optics and Optical Communications
Optical System in One-Point to Multi-Point Simultaneous Space Laser Communications
Jiang Lun, Hu Yuan, Wang Chao, An Yan, Dong Keyan, and Zhang Lizhong
With the development of free space laser communication technology and the demand of anti-jamming, high-speed integrated information network, the research of high-rate laser communication networking technology is urgent. Based on the analysis of the technical difficulty in space laser communication networking, a new lasWith the development of free space laser communication technology and the demand of anti-jamming, high-speed integrated information network, the research of high-rate laser communication networking technology is urgent. Based on the analysis of the technical difficulty in space laser communication networking, a new laser communication networking solution is proposed. Wide-angle beam expanders and double optical wedge groups are incorporated as antenna for the multi-point optical laser communication system. The wide-angle beam expander can collect the target signal lights in different directions, and the double optical wedge group can dynamically track different targets simultaneously. The overall scheme of multipoint free space laser communications based on this optical antenna is studied. The optical antenna, relay optical subsystem, transceiver subsystem and so on are designed. The scheme provides a new technical pathway for space laser communication network..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 506001 (2016)
1.5 μm Fiber Gas Raman Laser Source
Chen Yubin, Gu Bo, Wang Zefeng, and Lu Qisheng
A 1.5 μm fiber laser generation experiment in gas-filled hollow-core fiber by stimulated Raman scattering is reported. A high pressure ethane-filled hollow-core fiber is pumped with a high peak-power, narrow linewidth, subnanosecond pulsed 1064 nm microchip laser. The 1553 nm pulse with peak power of 16.6 kW is generatA 1.5 μm fiber laser generation experiment in gas-filled hollow-core fiber by stimulated Raman scattering is reported. A high pressure ethane-filled hollow-core fiber is pumped with a high peak-power, narrow linewidth, subnanosecond pulsed 1064 nm microchip laser. The 1553 nm pulse with peak power of 16.6 kW is generated via stimulated Raman scattering of ethane. The linewidth is less than 0.2 nm and the pulse duration is about 435 ps. To the best of our knowledge, the peak power obtained here is more than four times of the highest value reported for erbium-doped fibers. The study provides a technical pathway for 1.5 μm fiber laser with both high peak-power and narrow linewidth..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 506002 (2016)
Geometric Optics
Moving Accumulative Computation Method for Flux Distribution of Heat Absorber in Symmetry Concentrating Solar Collector System
Yan Jian, Peng Youduo, Cheng Ziran, and Yu Jiahuan
Based on the characteristics of geometric symmetry of the concentrating solar collector system, a moving accumulative method is put forward, which is used to compute the solar flux distribution of the absorber. Using the ray tracing method to deduce the moving accumulative mathematical model of the absorber flux distriBased on the characteristics of geometric symmetry of the concentrating solar collector system, a moving accumulative method is put forward, which is used to compute the solar flux distribution of the absorber. Using the ray tracing method to deduce the moving accumulative mathematical model of the absorber flux distribution, the model can effectively convert the ray tracing process into rotary or rectilinear motion. Therefore, the numerous equations of rays and absorber calculation are avoided. The moving accumulative programs are compiled and the absorber solar flux distributions of the dish system and parabolic trough system are calculated by Visual C++ software. Then the results are compared with references, which validate the correctness of the moving accumulative mathematical model. The result shows that, in dish system with cavity receiver, calculation of 6.10×108 rays need 112 s, but calculation of 9.648×107 rays just need 16 s and calculated results are basically consistent. The moving accumulative method calculation process is relatively simple and the computational efficiency is improved, which can provide reference to collaborative optimization for the symmetry solar concentration and collector system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 508001 (2016)
Imaging Systems
Selection of Benchmark Sub-Mirror of Sparse Aperture Based on Phase Diversity
Fan Junliu, Wu Quanying, Li Xunwu, Chen Baohua, Jiang Hui, and Lu Zhiyi
The principle of phase diversity(PD) is firstly introduced. The effect of the benchmark sub-mirror of sparse aperture imaging system on PD is illustrated. Taking Golay3 sparse aperture as an example, the object is imaged by each sub-mirror of the imaging system. The arithmetic mean standard deviation(AMSD) between imagThe principle of phase diversity(PD) is firstly introduced. The effect of the benchmark sub-mirror of sparse aperture imaging system on PD is illustrated. Taking Golay3 sparse aperture as an example, the object is imaged by each sub-mirror of the imaging system. The arithmetic mean standard deviation(AMSD) between images of each sub-mirror and the original object is calculated, and the sub-mirror with minimum AMSD value is selected as the benchmark sub-mirror. The influence of errors of the benchmark sub-mirror which are unknown practically on the accuracy of error estimation of the other sub-mirrors is analyzed. The impact of the defocus amount on the results of PD is also discussed. It is shown that the benchmark sub-mirror must be confirmed before error estimation of the other sub-mirrors of the sparse aperture imaging system with PD. The smaller the AMSD value is, the smaller the error of the corresponding sub-mirror is, the smaller the error of the residual sub-mirrors in the system calculated by PD method is, while the variation of the defocus amount has little influence on PD results..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 511001 (2016)
Sea Sky Line Detection Method of Unmanned Surface Vehicle Based on Gradient Saliency
Wang Bo, Su Yumin, Wan Lei, Zhuang Jiayuan, and Zhang Lei
Unmanned surface vehicle (USV) plays a more and more important role in various areas such as meteorological monitoring, maritime search and rescue, enemy reconnaissance, and precision strike. However, special features in real marine environment such as cloud clutter, sea glint, and weather conditions result in various Unmanned surface vehicle (USV) plays a more and more important role in various areas such as meteorological monitoring, maritime search and rescue, enemy reconnaissance, and precision strike. However, special features in real marine environment such as cloud clutter, sea glint, and weather conditions result in various kinds of interference in optical images, which makes it very difficult to detect the sea sky line accurately. To solve this problem, a sea sky line detection method is proposed based on gradient saliency. The line features of sea sky line are enhanced effectively through the computation of gradient saliency; other interference factors are suppressed; sea sky line detection and identification are achieved by region growing method. In the end, the proposed method is tested on optical images from “XL” USV in real marine environment and the experimental results demonstrate that the proposed method is significantly superior to other state-of-the-art methods in terms of detection rate and real-time performance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 511002 (2016)
Computational Reconstruction Algorithm for Integral Imaging Based on Diffraction Tracing
Fan Guangfei, Chen Linsen, Wei Guojun, and Gu Xinyu
Depth plane reconstructed by ray tracing algorithm in diffraction limited integral imaging is the refocused image of the object depth. But the image quality is blurring, which is not conducive to three dimensional reconstruction of the object. To solve these problems, a depth plane reconstruction algorithm based on difDepth plane reconstructed by ray tracing algorithm in diffraction limited integral imaging is the refocused image of the object depth. But the image quality is blurring, which is not conducive to three dimensional reconstruction of the object. To solve these problems, a depth plane reconstruction algorithm based on diffraction tracing is proposed. The light field distribution on each optical element surface in the imaging system spread from the point source of the object space, is orderly calculated by the Fresnel diffraction formula, and the intensity pulse response of each sample point on the sensor is obtained finally. Depth plane image is reconstructed by solving the linear equation group related to the intensity pulse response. The simulation results show that the reconstructed image is depth slice of the object, and the image quality is close to the original image, which is beneficial to three dimensional reconstruction of the object..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 511003 (2016)
Liquid Crystal Microlens Array for Dual Mode Imaging
Lei Yu, Tong Qing, and Zhang Xinyu
A transparent hole patterned liquid crystal microlens array is designed and fabricated via ultraviolet photolithography and wet etching based on nematic liquid crystal materials for its anisotropy and birefringence. An optical testing system is set up to evaluate its focusing performance and focal length, and the relatA transparent hole patterned liquid crystal microlens array is designed and fabricated via ultraviolet photolithography and wet etching based on nematic liquid crystal materials for its anisotropy and birefringence. An optical testing system is set up to evaluate its focusing performance and focal length, and the relationship between the focal length and the applied voltage is given. The array is coupled with a main lens and an image sensor to constitute a prototype of dual mode imaging camera, which can switch instantly between plenoptic imaging and normal imaging by turning on or off the applied voltage signals. Raw images are acquired in the two modes. It is obvious that the camera can capture three-dimensional plenoptic images in the plenoptic mode, as well as normal images in the normal mode..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 511004 (2016)
Transmission Stereo Microscope Based on Programmable LED Array Illumination
Kong Fucheng, Zhang Yuzhen, Sun Jiasong, Chen Qian, and Zuo Chao
A transmission stereo microscope is presented based on programmable light emitting diode（LED） array illumination so as to realize stereo imaging with high quality. The programmable LED array is the illumination source of this optical system. The radius, angle and wavelength of illumination can be chosen freely. The depA transmission stereo microscope is presented based on programmable light emitting diode（LED） array illumination so as to realize stereo imaging with high quality. The programmable LED array is the illumination source of this optical system. The radius, angle and wavelength of illumination can be chosen freely. The depth of focus and the stereotype angle can be adjusted by changing r and d of the programmable LED array at will. Experimental results show that the microscope system is simple, and double images which can not be coincided owning to the difference of individual pupil distance can be solved effectively by choosing appropriate r and d. The stereo image of samples can be obtained in details directly. The three-dimensional information such as hierarchy and relative position can be observed with optimal parameters r=2 and d=3 by using objective NA=0.1(4×)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 511005 (2016)
Instrumentation, Measurement and Metrology
Infrared Small Target Detection Method Based on Correlation Filter
He Yujie, Li Min, Zhang Jinli, and Xing Yuhang
To solve the infrared target real-time detection problems caused by low signal to noise ratio with complex background, an infrared small target detection method based on correlation filter is proposed. The small target detection problem is transformed into pattern classification task, which consists of two stages: off-To solve the infrared target real-time detection problems caused by low signal to noise ratio with complex background, an infrared small target detection method based on correlation filter is proposed. The small target detection problem is transformed into pattern classification task, which consists of two stages: off-line training and on-line detection. In training stage, a correlation filter is obtained using the training dataset produced by two-dimensional Gaussian model. It has ability to distinguish target and background. In detection stage, the sub-image blocks of the infrared image are extracted successively and the filtering response confidence map which indicates the target location is computed. The experiments under two conditions demonstrate that the proposed method not only has better detection performance with effective reduction of the false alarm rate, but also has better real-time performance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 512001 (2016)
Nanoscale Focusing and Leveling Measurement Technology Based on Optical Spatial Split
Sun Yuwen, Li Shiguang, and Zong Mingcheng
With the development of semiconductor manufacturing to 1x nm technological node, the measurement accuracy of the focusing and leveling system is down to several tens of nanometers. In the range of nanoscale, integrated circuit (IC) process plays an important impact on the measurement accuracy of the focusing and leveliWith the development of semiconductor manufacturing to 1x nm technological node, the measurement accuracy of the focusing and leveling system is down to several tens of nanometers. In the range of nanoscale, integrated circuit (IC) process plays an important impact on the measurement accuracy of the focusing and leveling system. A kind of focusing and leveling measurement technology based on optical triangulation and moiré fringes method is proposed. Two sets of moiré fringes with π phase difference are imaged onto two detectors using the spatial splitting system. The height of wafer is calculated by normalized differential method. The sensitivity of the system on the IC process, especially on the light intensity fluctuations is reduced. Experimental results show that the measurement repeatability of the system is 8 nm (3σ) and the linear accuracy is 18 nm (3σ). When the light intensity fluctuates 90%, the linear accuracy changes 15 nm (3σ). When the light intensity fluctuates 65%, the linear accuracy changes less than 1 nm (3σ)..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 512002 (2016)
Lasers and Laser Optics
Influence of Electron Density Distribution Induced by Single Beam Femtosecond Laser on Doubly-Periodic Nanogratings
Gong Min, Dai Ye, Song Juan, and Ma Guohong
The characteristics of nanogratings including damage trace, structure and birefringence properties, which are induced in fused silica by 1 kHz femtosecond laser pulses with different pulse energy, are studied. Two different periodic nanostructures are observed at the top of laser irradiation area, the primary structureThe characteristics of nanogratings including damage trace, structure and birefringence properties, which are induced in fused silica by 1 kHz femtosecond laser pulses with different pulse energy, are studied. Two different periodic nanostructures are observed at the top of laser irradiation area, the primary structure with the period ΛK in the direction of light propagation and the secondary structure with the period ΛE in the direction of laser beam polarization. The influence of incident energy flux density distribution and free electron density distribution on doubly-periodic nanogratings is investigated by numerically simulating the propagation process of femtosecond laser pulses inside the fused silica. The results show that higher incident energy flux density benefits the formation of nanogratings, and the generated electron density influences the period ΛK. The higher the electron density is, the longer the period ΛK is. The formation of doubly-periodic nanogratings is analyzed theoretically according to current experimental results. The asymmetric growth of plasma and the causing local intensity distribution affect the formation of doubly-periodic nanogratings..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 514001 (2016)
Machine Vision
Solution of Duality in Circular Feature with Three Line Configuration
Zhang Lijun, Huang Xuexiang, Feng Weichun, Liang Shuli, and Hu Tianjian
Due to the efficiency and accuracy, the visual measurement method based on circular features is widely used in computer vision applications. However, the duality problem interferes the process of monocular vision pose estimation with a single circle feature. In order to exclude of the false solution effectively, a methDue to the efficiency and accuracy, the visual measurement method based on circular features is widely used in computer vision applications. However, the duality problem interferes the process of monocular vision pose estimation with a single circle feature. In order to exclude of the false solution effectively, a method utilizing angular constraint to solve the ambiguity is proposed based on the attitude estimation with the three lines configuration. For a known three lines configuration, an angular constraint about the normal vector of the single circle is deduced with the attitude between the configuration and the camera coordinate. If the three lines configuration is unknown, an angular constraint between the normal vectors of the circle in two camera views is deduced with the relative attitude estimation with a pair of matched three lines configuration. Both of the angular constraints can be applied to exclude the false normal vector of the circle. Experimental results indicate that the proposed approach can effectively solve the duality problem. The success rate is up to 99.2% for the first angular constraint, and the success rate is up to 96.7% for the second angular constraint..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 515001 (2016)
Evaluation Strategy for Camera Pose Estimation Algorithm Based on Point Correspondences
Liu Jinbo, Guo Pengyu, Li Xin, and Zhang Xiaohu
Camera pose estimation algorithm based on point correspondence is lack of scientific performance evaluation method, which increases the selection difficulty for algorithms in the engineering applications. Aimed at the problem, the evaluation strategy for camera pose estimation algorithm under specific cost function is Camera pose estimation algorithm based on point correspondence is lack of scientific performance evaluation method, which increases the selection difficulty for algorithms in the engineering applications. Aimed at the problem, the evaluation strategy for camera pose estimation algorithm under specific cost function is put forward, mainly including three performance evaluation parameters: precision, efficiency and success rate of domain optimal solution. Domain optimal solution is different from local optimal solution. If a given area is at the definition domain of cost function, the optimal solution of this area is equivalent to the global optimal solution. The judgment method of domain optimal solution is described emphatically, the cost function is set up based on angle residual, and the lower bound Hessian matrix of cost function is calculated using attitude matrix. If lower bound of Hessian matrix is positive semi-definite, the cost function is convex function in the neighborhood that centers on pose matrix and the size is confirmed by the image point noise model. There exists optimal solution in given domain. In virtue of simulation experimental platform, nine classical camera pose estimation algorithms performance are evaluated. Results indicate that the comprehensive performance of RPnP+LHM method is the best..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 515002 (2016)
Arm Vein Feature Extraction and Matching Based on Chain Code
Zhao Shan, Wang Biao, and Tang Chaoying
A feature extraction and matching algorithm is proposed based on chain code to study the arm vein. The skeleton structure of the vein is extracted from the near infrared images of the arm and then divided into several curve segments. Matched curve pairs are calculated based on the relative direction, relative location A feature extraction and matching algorithm is proposed based on chain code to study the arm vein. The skeleton structure of the vein is extracted from the near infrared images of the arm and then divided into several curve segments. Matched curve pairs are calculated based on the relative direction, relative location and shape features of curves, and then the spatial transformation between the matched curve pairs is obtained with the particle swarm optimization algorithm. The matching probability is calculated based on the overlapping ratio of all the transformed vein points. The experiment on a database composed of arm images of 110 subjects from 9 countries shows that the identification rates for rank-1 and rank-10% are 74.5% and 93.6%, respectively, which is superior to the results obtained with algorithms of modified Hausdorff distance and template matching. It indicates that arm veins can be used as a new biometric feature for identity recognition..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 515003 (2016)
Calibration Method Based on Lattice Calibration Plate in Vision Measurement System
Duan Zhenyun, Wang Ning, Zhao Wenhui, and Zhao Wenzhen
In the application of machine vision technology for measurement, the factors of pixel equivalent, system errors and light source intensity in measurement system affect measuring accuracy. In order to improve the measuring accuracy, the pixel equivalent and system errors must be calibrated, and we need to analyze light In the application of machine vision technology for measurement, the factors of pixel equivalent, system errors and light source intensity in measurement system affect measuring accuracy. In order to improve the measuring accuracy, the pixel equivalent and system errors must be calibrated, and we need to analyze light source intensity which influences edge location of work piece image. An integrated calibration method based on lattice calibration plate in vision measurement system is put forward. On the basis of extracting center coordinates of calibration circle, pixel equivalent is got by calculating the center distance of physical value and pixel value. The error model with the actual coordinates and theoretical coordinates of center point is established, the error model coefficients are got by the least squares fitting. By determining the compensation amount of image edge position error caused by light source intensity, composite calibration of measurement system is achieved. The experimental results show that this method can effectively improve the measurement precision..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 515004 (2016)
Materials
Detection of Mitoxantrone Based on Mn-Doped ZnS Quantum Dots/CTAB Nanohybrids
Wu Yuxia, Miao Yanming, Yang Maoqing, Li Yan, and Yan Guiqin
With 3-mercaptopropionic acid as the stabilizer, Mn-doped ZnS quantum dots (QDs) are synthesized via the water phase method. These QDs emit strong phosphorescence at room temperature. These QDs aggregate with cetyl trimethylammonium bromide (CTAB) as a cation surfactant through electrostatic interaction to form Mn-dopeWith 3-mercaptopropionic acid as the stabilizer, Mn-doped ZnS quantum dots (QDs) are synthesized via the water phase method. These QDs emit strong phosphorescence at room temperature. These QDs aggregate with cetyl trimethylammonium bromide (CTAB) as a cation surfactant through electrostatic interaction to form Mn-doped ZnS QDs/CTAB nanohybrids, thereby largely enhancing the room-temperature phosphorescence (RTP) of QDs. The newly-added mitoxantrone (MXT) binds with CTAB through hydrophobic interaction and structure function to form more stable mixture, leading to separation of CTAB from the QD surfaces and reduction of the QD RTP intensity. The results indicate the nanohybrids can significantly improve the QD-based MXT detection ability. Thereby, a high-performance and high-sensitivity RTP sensor for MXT detection is established. Under the optimal conditions, this sensor has a MXT detection limit of 0.23 nmol/L and linear range from 0 to 200 nmol/L (correlation coefficient R=0.99). The results with real urine and serum samples are with recovery rate of 98.6%～102.5%. The phosphorescence detection method is simple, rapid, sensitive and selective, and can be used well for analysis and detection of MXT in body fluid..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 516001 (2016)
Simulation of Anti-Reflection and Light-Trapping Property of Bio-Inspired Silicon Structure
Pan Feng, Zhang Wang, and Zhang Di
The silicon nanocone structure bio-inspired from the protuberances on the cicada wing is studied for its anti-reflection and light-trapping property. The average reflectivity of the nanocone can be reduced to 1% in the spectral range of from 300 nm to 1200 nm with optimal parameters of 150 nm bottom radius and 500 nm hThe silicon nanocone structure bio-inspired from the protuberances on the cicada wing is studied for its anti-reflection and light-trapping property. The average reflectivity of the nanocone can be reduced to 1% in the spectral range of from 300 nm to 1200 nm with optimal parameters of 150 nm bottom radius and 500 nm height. The optimized nanocone structure is compared with the slab structure and nanorods structure with the same parameters. The superior anti-reflection and absorption properties are further demonstrated by reflection curve, electrical field intensity distribution, absorption per unit volume and electron generation rate distribution. The simulation result may provide guidance for the design of anti-reflection and light-trapping microstructure in silicon photovoltaic devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 516002 (2016)
Effect of Anisotropic Materials on Dirac Point in Two-Dimensional Photonic Crystals Arranged in a Hexagonal Lattice
Wen Fei, Xie Kang, and Zhang Wei
Dirac point in photonic band structures is a research focus in the present photonic crystal field. The hexagonal rods arranged in a hexagonal lattice anisotropic photonic crystals using bi-axial materials are presented. In the photonic crystals, there are three different primary dielectric constants, εxx,εyy and εzz. BDirac point in photonic band structures is a research focus in the present photonic crystal field. The hexagonal rods arranged in a hexagonal lattice anisotropic photonic crystals using bi-axial materials are presented. In the photonic crystals, there are three different primary dielectric constants, εxx,εyy and εzz. Based on the Maxwell’s equations, the Dirac point in transverse electric (TE) wave is affected by εxx≠εyy. The Dirac velocity in the TE wave can be obtained by modulating the principal refractive index Nx and Ny in the X and Y directions of bi-axial materials, and thus the position of the Dirac point in the energy band structure can be changed by adgusting TE wave. That is to say, the normalized frequency of the Dirac point and its position in the Brillouin zone can be changed. The relationship between Nx, Ny (corresponding to εxx, εyy) and existence of the Dirac point in TE wave is studied, and the proposed opinion is demonstrated by simulation experiments. The characteristics will provide more possibility for the design of novel photonic components and photonic chip architectures..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 516003 (2016)
Medical Optics and Biotechnology
Assessment of Mental Workload Influenced by Different Emotional State Using fNIRS
Jiang Jin, Jiao Xuejun, Pan Jinjin, Wang Chunhui, Zhang Zhen, Cao Yong, Yang Hanjun, and Xu Fenggang
In order to investigate the feasibility of mental workload (MWL) assessment influenced by different emotional state by using the functional near-infrared spectroscopy (fNIRS) and to support the operator functional state (OFS) assessment based on the MWL assessment, the picture n-back experiments stimulated by multiple In order to investigate the feasibility of mental workload (MWL) assessment influenced by different emotional state by using the functional near-infrared spectroscopy (fNIRS) and to support the operator functional state (OFS) assessment based on the MWL assessment, the picture n-back experiments stimulated by multiple emotions, including negative, neutral and positive emotions, are conducted. The experiment data of 16 participants are collected by the means of task performance, subjective rating and fNIRS physiological measurement. The results show that the MWL of participants is affected by external factors in terms of task performance and subjective rating. An MWL assessment model is established, with a total of 380 physiological features of time domain, frequency domain and nonlinearity domain extracted from the fNIRS information as input and the support vector machine as classifier. Average accuracy of classification is 92.49% for training data which is based on task data stimulated by neutral emotion, and 75.9% and 79.99% for test data which is based on experiment data stimulated by positive and negative emotions. By analyzing the data, the experiments verify the hypothesis that the operator′s MWL is effectively affected by task load and emotional stimulus, demonstrate the feasibility of MWL assessment in different emotional state based on fNIRS, and lay a foundation for the OFS assessment on the strength of the MWL evaluation during complex tasks..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 517001 (2016)
Nonlinear Optics
Theoretical and Experimental Study on Parametric Fluorescence Pulse Width
Wang Bopeng, Su Jingqin, Zeng Xiaoming, Wang Xiaodong, Wang Xiao, Zhou Kainan, Guo Yi, Zhu Qihua, and Jing Feng
Parametric fluorescence is the intrinsic quantum noise of optical parametric amplifiers based on optical parametric chirped pulse amplification(OPCPA) technology. It does not have the same temporal chirp characteristics with the main laser, forms an incompressible pulse base in the compressor, and reduces the signal-toParametric fluorescence is the intrinsic quantum noise of optical parametric amplifiers based on optical parametric chirped pulse amplification(OPCPA) technology. It does not have the same temporal chirp characteristics with the main laser, forms an incompressible pulse base in the compressor, and reduces the signal-to-noise ratio of the laser pulse. In the case of small signal gain, the evolution laws of parametric fluorescence pulse width with different pump profiles, gains, system bandwidths and chirp rates are given based on the analytical formula. Results show that the single stage amplifier output fluorescence pulse width is proportional to the pump pulse width, and it decreases with the gain increasing. With a constant gain, the fluorescence pulse width becomes larger with the increase of the super Gaussian wave order. For OPCPA system, the stretch-compression system has the effect of dispersion broadening,so the final output fluorescence pulse width is closely related to the system bandwidth and chirp rate. Based on peta-watt OPCPA (PW-OPCPA) experimental platform, the relevant verification experiments are carried out, and the experimental results are in good agreement with the theoretical results..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 519001 (2016)
Design of Multiple-Wavelength Frequency Conversion Device Based on Intensity Distribution
Ren Kun, Liu Yali, Ren Xiaobin, and Fan Jingyang
Controllable frequency conversion devices, with the generation of multiple-wavelength, are designed. We analyze the variation of light intensity in nonlinear crystal with propagation distance. A method is proposed to design nonlinear structure based on the distribution of light intensity. MATLAB software is used to simControllable frequency conversion devices, with the generation of multiple-wavelength, are designed. We analyze the variation of light intensity in nonlinear crystal with propagation distance. A method is proposed to design nonlinear structure based on the distribution of light intensity. MATLAB software is used to simulate sum frequency generation. An aperiodic structure is obtained to achieve simultaneous six sum-frequency-generations. The weighting coefficient is introduced to flexibly modify output intensity and obtain objective spectrum with arbitrary shape. By analyzing sum-frequency-generation and second-harmonic-generation, the obtained structure can not only generate multiple-wavelength, but also arbitrarily adjust the optical power of output wavelength. Our proposed method has advantages of fast speed and high efficiency. It can provide a good guidance for the fabrication of nonlinear optical devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 519002 (2016)
Optical Design and Fabrication
Free-Form Optical Elements Corrected Aberrations of Optical System
Pang Zhihai, Fan Xuewu, Ma Zhen, and Zou Gangyi
The optical element of free-form surface can be expressed by the fringe Zernike polynomial and the terms of initial spherical sag, coma and astigmatism are transformed into the vector forms. Based on the vector wave aberration theory, the free-form optical element characteristic of optical system initial aberration corThe optical element of free-form surface can be expressed by the fringe Zernike polynomial and the terms of initial spherical sag, coma and astigmatism are transformed into the vector forms. Based on the vector wave aberration theory, the free-form optical element characteristic of optical system initial aberration correction is analyzed. Through the analysis, the free-form surfaces in optical system have different aberration emendation specialties at different positions. The free-form optical element can be corrected in full field of view for constant initial aberration as a stop aperture (entrance pupil or exit pupil) in optical system. When the free-form surface is far from the stop aperture of optical system, due to the scaling and offset of the imaging beam aperture for an off-axis field point, the free-form surface can correcte the asymmetric initial aberration, and the relationship of different initial aberration and field of view is different..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 522001 (2016)
Optical Design of Visible and Infrared Integrative Camera
Li Ruichang, Zou Gangyi, Wang Chenchen, and Fan Xuewu
The spatial resolution, time resolution and spectral resolution of the space remote sensing camera are improved gradually, the spectral band for observation of the camera is also extended and the multispectral observation is realized. The design of visible and infrared integrative optical system is studied based on theThe spatial resolution, time resolution and spectral resolution of the space remote sensing camera are improved gradually, the spectral band for observation of the camera is also extended and the multispectral observation is realized. The design of visible and infrared integrative optical system is studied based on the need of multispectral observation. The design is accomplished through calculation and an optical design software. In this design, the system focal length of the visible part is 6000 mm, F number is 11.8 and the wavelength band is 400~900 nm. The system focal length of the infrared part is 1280 mm, F number is 2.5 and the wavelength band is 3000~5000 nm. The field of view is 1.4°×0.6° for both of the systems. The visible band system and the infrared band system share the first four mirrors, the fifth is a dichroic mirror and reflects the visible light to the time delayed and integration CCD which is over the fifth mirror. The infrared light passes through the fifth mirror to the rear lens set for correction. The whole system has no color aberration, its structure is compact, and the image quality for visible and infrared is up to par..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 522002 (2016)
Design of Freeform Surface Lens for Shaping Divergent Laser Beam
Peng Yameng, and Su Zhouping
A design method of laser beam shaping freeform surface lens is proposed, which can be applied to shape the diverging laser beam. Freeform surface lens design is a two-step process. Firstly, an initial lens layout is designed by establishing the input-output energy mapping relationship. Then, the reverse feedback optimiA design method of laser beam shaping freeform surface lens is proposed, which can be applied to shape the diverging laser beam. Freeform surface lens design is a two-step process. Firstly, an initial lens layout is designed by establishing the input-output energy mapping relationship. Then, the reverse feedback optimization method is used to optimize the initial freeform lens when the divergent beam is applied. By this method, a freeform lens is designed for shaping a laser beam with beam waist of 10 mm and a half divergence angle of 2.5°. The simulation results show that the freeform lens can transform a Gaussian beam into a 40 mm×40 mm top-hat beam with an irradiance uniformity of 90.4%. Finally, the machining error analysis and the assembly tolerance analysis of the freeform lens are performed. It is shown that the uniformity is almost unchanged while the process error varies from -5 μm to 5 μm. And the longitudinal deviation error dz has little influence on the irradiance uniformity, but the lateral deviation error dx and slant angle error dφ have a significant influence on the irradiance uniformity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 522003 (2016)
Study on Bionic Moth-Eye Antireflective Cylindrical Microstructure on Germanium Substrate
Dong Tingting, Fu Yuegang, Chen Chi, Zhang Lei, and Ma Chenhao
Based on the rigorous coupled wave analysis method, the diffraction characteristics of bionic moth-eye antireflective cylindrical microstructure is researched at long wave infrared wavelengths. By theoretical analysis and simulation, the effects of the moth-eye microstructure parameters, such as period, depth, filling Based on the rigorous coupled wave analysis method, the diffraction characteristics of bionic moth-eye antireflective cylindrical microstructure is researched at long wave infrared wavelengths. By theoretical analysis and simulation, the effects of the moth-eye microstructure parameters, such as period, depth, filling factor, profile shape in actual manufacturing process on their reflectivity, are discussed. A structure parameters combination is optimized to obtain low reflection. The sub-wavelength period microstructure on germanium substrate is fabricated by binary exposure and reactive ion etching technology. The surface topography is analyzed by thermal field emission scanning electron microscopy, the infrared imaging spectrometer is applied to contrast the germanium wafer with double sides polishing, single-sided and double-sided moth-eye microstructures. The measurement results illustrate that the reflection efficiency of the double-sided microstructures is less than 8% at 8~12 μm wavelength, which achieves the design requirements..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 522004 (2016)
Optical Devices
Talbot Effect of Square-Aperture Microlens Array
Zhang Baohao, Zhou Sumei, Yang Xiaoming, and Zheng Sanchao
The Talbot effect of the square-aperture microlens array is studied theoretically and experimentally. The complex wave amplitude distribution of this array in the Fresnel diffraction field is analyzed with the optical transfer function to resolve the imaging situation of Talbot image. In the experiment, three alternatiThe Talbot effect of the square-aperture microlens array is studied theoretically and experimentally. The complex wave amplitude distribution of this array in the Fresnel diffraction field is analyzed with the optical transfer function to resolve the imaging situation of Talbot image. In the experiment, three alternating images appear at certain distances, and the experimentally measured imaging distance is consistent with the theoretical prediction. In addition, the Talbot sub-image imaging law is invariant when the parameters of the square-aperture microlens array change. The Talbot sub-image image elements overlap, when the center distance is between one and two aperture diameters. The clear Talbot sub-images with checkerboard-shaped distributions of the square-aperture microlens array are observed in the fractional Talbot planes. It will broaden the practical application of the square-aperture microlens array..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 523001 (2016)
Optics at Surfaces
Thermal Index Based on Surface Plasmon Resonance
Liu Xiaofei, Zhang Xueru, Lan Guoqiang, Li Shuqing, and Liu Yang
The thermal accumulative effect of liquids induced by laser illumination gives rise to the refractive-index change. On the basis of photo-acoustic equations, the mechanism on the transient-state and steady-state thermal indexes of the liquids can be analyzed, respectively. Moreover, the effects of the incident wavelengThe thermal accumulative effect of liquids induced by laser illumination gives rise to the refractive-index change. On the basis of photo-acoustic equations, the mechanism on the transient-state and steady-state thermal indexes of the liquids can be analyzed, respectively. Moreover, the effects of the incident wavelength and focal length on the refractive index of deionized water are studied. Using surface plasmon resonance detection system that is highly sensitive to temperature alteration, an original liquid prism detection system is set up, and the resonance curve of the deionized water at various power levels is numerically simulated from which refractive-index change of 1.4×10-3 in the case of power change of 0.7 W is obtained. Then the experimental researches on thermo-optical effect of the deionized water are carried out by means of continuously operating laser of 980 nm wavelength with adjustable power levels, and the dependences of steady-state thermal index on different power levels are obtained. It is observed that the refractive-index change reach 3.35×10-3 when power change is 0.7 W. Finally, possible error sources between the experimental results and the theoretical simulation are discussed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 524001 (2016)
Quantum Optics
Entanglement Characteristics in Two-Dimensional Coupled Cavity Systems
Qiu Changdong, and Lu Daoming
The interaction system of four identical two-level atoms and two-dimensional coupled single-mode optical cavities is studied in which the atoms are trapped separately in the cavities, and each atom resonantly interacts with the cavity via a one-photon hopping. Negativity is used to quantify the degree of entanglement bThe interaction system of four identical two-level atoms and two-dimensional coupled single-mode optical cavities is studied in which the atoms are trapped separately in the cavities, and each atom resonantly interacts with the cavity via a one-photon hopping. Negativity is used to quantify the degree of entanglement between two subsystems. The influences of cavity-cavity coupling coefficients on the atom-atom entanglement and the cavity-cavity entanglement are discussed based on the numerical calculation results. The obtained results show that the atom-atom entanglement is strengthened while the cavity-cavity entanglement is weakened with the increase of cavity-cavity coupling coefficient..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 527001 (2016)
Dynamics of Inversion-Symmetry Breaking Rabi Model
Dong Kun
The inversion-symmetry breaking Rabi model under ultra-strong coupling condition is studied with the adiabatic approximation method. The analytical expressions of the eigenfunctions and the eigenvalues are obtained, and the influence of the inversion-symmetry breaking on them is also studied. The dynamical behavior of The inversion-symmetry breaking Rabi model under ultra-strong coupling condition is studied with the adiabatic approximation method. The analytical expressions of the eigenfunctions and the eigenvalues are obtained, and the influence of the inversion-symmetry breaking on them is also studied. The dynamical behavior of the system, with initial status of Fock state and coherent state for the quantum harmonic oscillator, is discussed. The collapse and revival phenomena have been put particular attentions. The results show that the inversion-symmetry breaking changes the time and height of collapse and revival..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 527002 (2016)
Remote Sensing and Sensors
Simulation and Analysis of Point Target Detection Performance for Infrared Scanning Over-Sampling System
Lin Liangkui, Wang Shaoyou, and Wang Tiebing
The over-sampling is a novel imaging scheme for improving resolution of remote sensing scanning images. If the scheme is employed by the infrared search and track system, it is necessary to analyze the effect of the over-sampling on the point target detection performance. The characteristics of over-sampling imaging arThe over-sampling is a novel imaging scheme for improving resolution of remote sensing scanning images. If the scheme is employed by the infrared search and track system, it is necessary to analyze the effect of the over-sampling on the point target detection performance. The characteristics of over-sampling imaging are compared to those of the standard sampling with respect to the scanning imaging principle. Based on degradation of high-resolution image, a method of scanning image simulation is proposed. The scanning images including objects are simulated and processed by a typical single-frame target detection algorithm, and the detection performance of the two sampling schemes is analyzed. Experimental results show that under the same conditions, the point target detection performance of the over-sampling scheme is better than the standard sampling. The scanning image of standard sampling for target is generally a 1×1 point, while the over-sampling scheme creates pixel-clutter for target. The characteristic can improve the target detection performance further..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 528001 (2016)
Application of Spatial Variance Construction in Correction of Pile-Up Effects of Lidar Photon-Counting Data
Gao Fei, Li Songhui, Li Wanwan, Wang Li, Xin Wenhui, and Hua Dengxin
Due to the strong intensity of lidar return signal in the near field, the photon-counting system in lidar applications suffers from the pile-up effect, which can be corrected by the parameter of dead time. A mathematical model is constructed to calculate the spatial variance, which is used to evaluate the quality of PoDue to the strong intensity of lidar return signal in the near field, the photon-counting system in lidar applications suffers from the pile-up effect, which can be corrected by the parameter of dead time. A mathematical model is constructed to calculate the spatial variance, which is used to evaluate the quality of Poisson distribution of lidar data. Furthermore, the analysis results of the spatial variance are utilized to estimate the dead time of the lidar photon-counting system and to correct the pile-up effect. The calculation results indicate that the photon-counting data in the far field of lidar conforms to the Poisson distribution, but the data in the near field does not. However, the Poisson distribution characteristic of the photon-counting data can be improved notably by the dead time correction. Therefore, the system dead time can be estimated by minimizing the deviation between the variance and the mean of lidar data. One can correct the pile-up effect of photon-counting data and make the data profile conform to the Poisson distribution at the maximum degree. The results show that the dead time of the photon-counting system in Licel transient recorder TR40-160 is approximately 3.402 ns, which is estimated by using the photon-counting data in the application of long-range scanning lidar. The pile-up effect in the presented photon-counting data is improved obviously..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 528002 (2016)
Scattering
Near Forward Light Scattering Characteristics of Airborne Particles
Wu Jinlei, Zhang Jinbi, Zhang Li, Ding Lei, Zheng Haiyang, Wang Yingping, and Fang Li
A near forward light scattering experimental apparatus is designed to investigate the light scattering properties of airborne particles and its applications in measurement of dust mass concentration. By experimental measurement and the Mie scattering theory for both monodisperse and polydisperse particulate matter sampA near forward light scattering experimental apparatus is designed to investigate the light scattering properties of airborne particles and its applications in measurement of dust mass concentration. By experimental measurement and the Mie scattering theory for both monodisperse and polydisperse particulate matter samples, the relationships between near forward light scattering intensity and particle diameter, size distribution are obtained. The results demonstrate that the experimental apparatus can be used to measure the aerosol mass concentration of airborne particles in ambient air. More accurate responsivity can be obtained through experimental measurement and the Mie scattering theory for known monodisperse aerosol samples, and it is possible to estimate the error range in measurement of ambient air particles. If calibrated with the ultrafine Arizona road dust, the mass concentration readings of urban aerosols should be corrected by multiplying a factor of 2.5..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 529001 (2016)
Spectroscopy
Fluorescence Spectrum Denoising Method for Low Concentration Petroleum Pollutants Based on EMD-LWT
Yang Zhe, Wang Yutian, and Pan Zhao
The petroleum pollutant is an important factor causing air pollution problems such as haze. The de-noising effectiveness is the focus in petroleum pollutant detection by fluorescence spectroscopy. A fluorescence spectrum de-noising method for low concentration petroleum pollutants combining the empirical model decomposThe petroleum pollutant is an important factor causing air pollution problems such as haze. The de-noising effectiveness is the focus in petroleum pollutant detection by fluorescence spectroscopy. A fluorescence spectrum de-noising method for low concentration petroleum pollutants combining the empirical model decomposition (EMD) and the lifting wavelet transform (LWT) is proposed. The EMD method can filter the noise in weak fluorescence signal adaptively, but the first intrinsic mode function (IMF) contains a too wide frequency range, and thus the de-noising accuracy and effectiveness is reduced. LWT is introduced to realize more precise decomposition of IMF1, extract more useful information from IMF1, and improve separation effect of signal and noise. The three de-noising methods, EMD-LWT, EMD and LWT, are applied to kerosene fluorescence spectrum detection, respectively. The simulation results show that the EMD-LWT method makes the signal-to-noise ratio，root mean square error significantly improved compared with only EMD or LWT used, verifying the effectiveness and feasibility of the proposed method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 530001 (2016)
CO Concentration Measurement Using Multi-Mode Laser Diode Absorption Spectroscopy near 1570 nm
Gao Guangzhen, and Cai Tingdong
A multi-mode diode laser absorption spectroscopy system is built by using a multi-mode diode laser with stable emission spectrum as light source. Combined with the long path absorption and harmonic detection techniques, concentration (volume fraction) measurement of CO is realized by detecting multiple absorption linesA multi-mode diode laser absorption spectroscopy system is built by using a multi-mode diode laser with stable emission spectrum as light source. Combined with the long path absorption and harmonic detection techniques, concentration (volume fraction) measurement of CO is realized by detecting multiple absorption lines near 1570 nm. The experiments are carried out at room temperature and 20.265 kPa (0.2 standard atmospheric pressure). By configuring different CO-N2 gas mixtures, a series of different concentrations of sample gases are measured. The system is calibrated by using nine kinds of CO-N2 mixtures with different concentrations. The calibration formula is obtained and used to inverse CO concentration. The results show that in the case of volume fraction below 10%, the consistency between the measured and known values is higher, and the average deviation between them is 2.57%. By analyzing the mixed gas measurement signal of 0.5% volume fraction, the system detection limit of CO is 3.03×10-5. The system can meet the on-line monitoring of CO, and it has high stability and high sensitivity. The experimental device is simple and easy to use..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 530002 (2016)
Thin Films
Study and Fabrication of Wide Angle and Broad Spectrum Gray Adjustment Film in Infrared Imaging System
Fu Xiuhua, Xiong Shifu, Liu Dongmei, Zhang Jing, and Zhang Yushuai
With the continuous development of modern optical testing technology, the requirement of image process technology is increasing. As the gray-scale level contains important information of image, changing gray levels of the image can make the image detail more clear. Using filter technology can form different gray levelsWith the continuous development of modern optical testing technology, the requirement of image process technology is increasing. As the gray-scale level contains important information of image, changing gray levels of the image can make the image detail more clear. Using filter technology can form different gray levels. Based on the optical thin film theory and combined with thin film design software, the design of a 3~5 μm thick filter film with incident angle of 0°~60° is achieved by establishing film optimization evaluation function. And using vacuum deposition technology, the gray adjustment film is fabricated. Adding copper mesh over the molybdenum boat can solve the problem of surface defects caused by the unstable deposition rate of SiO. The experimental results are simulated using reverse analysis method. The sensitive layer thickness of film system can be controlled by adjusting the film monitoring method. The controlled deviation of film thickness is reduced. So that the spectral curve is smoothed. After tests, the prepared film meets the requirement of gray adjustment in the infrared image system, and passes the relevant environmental tests..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 531001 (2016)
Ultrafast Optics
Investigation of Femtosecond Laser-Induced Periodic Surface Structure on Tungsten
Li Chen, Cheng Guanghua, and Stoian Razvan
Femtosecond laser-induced periodic surface structure (LIPSS) has the potential applications in tunable thermal source, tribology, super-hydrophilicity, super-hydrophobicity, marking and so on. LIPSS formation and mechanism on tungsten with a 800 nm femtosecond laser are investigated. The electromagnetic energy distribuFemtosecond laser-induced periodic surface structure (LIPSS) has the potential applications in tunable thermal source, tribology, super-hydrophilicity, super-hydrophobicity, marking and so on. LIPSS formation and mechanism on tungsten with a 800 nm femtosecond laser are investigated. The electromagnetic energy distribution on random rough surface after the first laser pulse and the energy distribution of electromagnetic field induced by low-spatial-frequency LIPSS after 20 pulses are simulated by Sipe interference model and finite-difference time-domain (FDTD) method. The formation mechanism of low-spatial-frequency and high-spatial-frequency LIPSS (HSFL) is disclosed. The evolution of surface morphology and the phenomena of spatial period decreasing with the increase of laser pulse number are also investigated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 532001 (2016)
Vision, Color, and Visual Optics
Evaluation and Optimization of Color Harmony Model with Context of Patch and Garment
Shi Chunjie, Huang Min, Li Zeyang, Liu Yu, and Wang Huizhe
In order to evaluate the existing color harmony models, 24 color centers uniformly distributed on the CIELAB color space are selected and the observers with normal color vision are organized to assess the color harmony of patches and garments scene. The results of color harmony obtained from the psychophysical experimeIn order to evaluate the existing color harmony models, 24 color centers uniformly distributed on the CIELAB color space are selected and the observers with normal color vision are organized to assess the color harmony of patches and garments scene. The results of color harmony obtained from the psychophysical experiment are used to test the existing color harmony principles and models. The results show that color harmony scores obtained from the patches and garments have a weak correlation coefficient (R2<0.126). Predicting results by existing color harmony models are unsatisfactory with experimental data (R2<0.5). Therefore a new patches color harmony model based on Ou model and a new garments color harmony model based on Luo&Ou model are optimized, and the performances are considerably improved in different application scenarios. The experimental results can provide a study method and reference for the prediction of color harmony..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 533001 (2016)
X-Ray Optics
A Technology of X-Ray Imaging Flat-Response Low-Pass Filter
Yuan Zheng, Cao Zhurong, Zhu Xiaoli, Deng Bo, Li Jin, Yang Zhiwen, Hong Caihao, Liu Shenye, Yang Jiamin, and Zhao Yidong
A X-ray imaging flat-response low-pass filter technology based on grazing incidence micro-cylinder mirror arrays is proposed. According to the X-ray optical theory, the principle of flat-response low-pass filter based on micro-cylinder mirror arrays is introduced and the computational method of the element transmissionA X-ray imaging flat-response low-pass filter technology based on grazing incidence micro-cylinder mirror arrays is proposed. According to the X-ray optical theory, the principle of flat-response low-pass filter based on micro-cylinder mirror arrays is introduced and the computational method of the element transmission spectrum is analyzed. A micro-cylinder array sample is fabricated on the substrate of polyimide by electron-beam lithography, with 200 nm column diameter, 1.3 μm height and 0.393 duty ratio. According to the theoretical calculation, when the glancing angle is 2°, the end-energy is 1250 eV and the unevenness is 5.7%. Transmission of this array is calibrated on 4B7B soft X ray beam line station of Beijing synchrotron radiation facility from several grazing-incidence angles, using a three dimensional precision angle institution of which the angular precision is better than 0.1°. The initial calibration result is attained. Calibration result shows that for all the grazing-incidence angles, the transmission presents on declining curve over 1 keV, and the downturn energy decreases as the angle increases. It demonstrates that the increase of glancing angle has an restraint effect on the high-energy X-ray. Because of the electron-beam lithography limits, the depth to width, side wall perpendicularity, side wall roughness and other parameters of the sample can not reach the theory requirement, thus the calibration result has an certain difference from the theoretical calculation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 36, Issue 5, 534001 (2016)
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