Journals >Acta Photonica Sinica
Contents
2020
Volume: 49 Issue 4
28 Article(s)
Export citation format
Atmospheric and Oceanic Optics
Lidar Inversion of PM2.5 Mass Concentration Vertical Distribution
Xing-long XIONG, Yong-dong LI, Shuai FENG, Jie WANG, and Yu-zhao MA
PM2.5 concentration distribution measurement in space at different heights is difficult, this paper uses lidar and atmospheric transmission meter and particle spectrometer for joint detection, through three kinds of instrument data with the vertical distribution of PM2.5 concentration inversion. The function relationshPM2.5 concentration distribution measurement in space at different heights is difficult, this paper uses lidar and atmospheric transmission meter and particle spectrometer for joint detection, through three kinds of instrument data with the vertical distribution of PM2.5 concentration inversion. The function relationship between mass concentration of ground PM2.5 and atmospheric transmissivity is established by data of atmospheric transmittance and particle size spectrometer. Based on the ground atmospheric transmittance measured by the atmospheric transmission meter, the boundary value of the lidar atmospheric transmittance at high altitude is determined through an iterative algorithm, and the vertical distribution of the atmospheric transmittance is retrieved in combination with Fernald integral method. The vertical distribution of PM2.5 mass concentration is obtained by the atmospheric transmittance height profile detected by lidar. The results showed that the accuracy of the vertical distribution of atmospheric transmittance has been improved by the revised atmospheric transmittance. The profile of PM2.5 mass concentration well reflects the microphysical variation of the vertical distribution of aerosols..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0401001 (2020)
Echo Signals Analysis of Side-scattering LiDAR under Different Wind Speed Conditions
Jia-qi SUN, Miao HU, Peng LI, Wen-di HE, Jun OU, Xue-fang ZHOU, Guo-wei YANG, Yang LU, and Mei-hua BI
The echo signals of the CCD side-scattering lidar under different wind speed conditions were analyzed. According to Mie scattering theory and CCD side-scattering LiDAR principle, the correlation between aerosol concentration and its side-scattering light intensity is determined. By considering the relationship between The echo signals of the CCD side-scattering lidar under different wind speed conditions were analyzed. According to Mie scattering theory and CCD side-scattering LiDAR principle, the correlation between aerosol concentration and its side-scattering light intensity is determined. By considering the relationship between aerosol concentration and wind speed, the echo signals of side scatter lidar under different wind speed conditions are analyzed. By comparing the experiments under two conditions of axial fan wind and natural wind, it can be found that when the wind speed is in the range of 1~4.5 m/s, the aerosol concentration increases with the increasing of wind speed; otherwise when the wind speed is in the range of 4.5~6 m/s, the aerosol concentration decreases with the increasing of wind speed.Normalizing the results, conclusions are drawn that when the wind speed are in the range of 1~4.5 m/s, the side-scattering light intensity increase by 3.7% and 3.9% with the wind speeds increase by 1 m/s in the conditions of axial fan and natural wind. When the wind speedsare in the range of 4.5~ 6.0 m/s, the light intensity decreased by 3.1% and 3.8% with wind speeds increases by 1 m/s in the two conditions, and the trend exists in all wind coming directions of natural wind..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0401002 (2020)
Detectors
Transient Luminescence Characteristics of Random Laser Emission Based on Electron Beam Pumping Perovskite Nanocrystals
Peng DU, Yi-ning MU, Hang REN, Hai-bo FAN, Yan ZHU, Yan-zheng LI, and Monroy IDELFONSO
In order to meet the requirement of instantaneous imaging technology for transient optical system, a method of instantaneous luminescence based on perovskite nanometer crystal random maser is proposed in this paper. Based on the preparation and characterization of CsPbBr3 nanometer crystal films, the preparation methodIn order to meet the requirement of instantaneous imaging technology for transient optical system, a method of instantaneous luminescence based on perovskite nanometer crystal random maser is proposed in this paper. Based on the preparation and characterization of CsPbBr3 nanometer crystal films, the preparation methods and means of similar active films are analyzed. Combined with the application needs, this paper designed the electron beam pumping structure with microchannel plate as the core, and verified the maser effect of CsPbBr3 nanometer crystal film under electron beam pumping through experiments, and analyzed its maser principle and physical phenomenon. Finally, the instantaneous advantage of CsPbBr3 nanometer crystal thin film is verified by instantaneous optical pumping. In the instantaneous detection system of the new developed film, not only has good transient characteristics and time resolution, but also can use the electron beam pumping to induce laser to form the second stage of light amplification, thus improving the overall detection ability of the device..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0404001 (2020)
Remote Sensing and Monitoring of Industrial SO2 and Carbon Black Particles with Ultraviolet Imaging Technology
Wei-min DUAN, Yuan-hui XIONG, Zhen-wei CHEN, Guang-bao YU, Lin-mei LIU, Fa-quan LI, and Kui-jun WU
In order to monitor industrial chimney emissions accurately and effectively, based on the optical properties of SO2 and carbon black particles, a dual-channel ultraviolet imaging remote sensing monitoring system was developed. The center wavelength of the two spectral channels were set at 310 nm and 330 nm, respectivelIn order to monitor industrial chimney emissions accurately and effectively, based on the optical properties of SO2 and carbon black particles, a dual-channel ultraviolet imaging remote sensing monitoring system was developed. The center wavelength of the two spectral channels were set at 310 nm and 330 nm, respectively. The SO2 concentration image was obtained by the optical thickness difference of the two channels, and the particles concentration image was obtained by the 330 nm channel. With the plume speed obtained from the density image by the Optical-flow method, the emission rates of SO2 and carbon black particle were calculated from them. The results show that the emission rates of SO2 and carbon black particles from the industrial chimney are 72.48±3.16 kg/h and 6.33±1.18 kg/h, respectively. In this experiment, the SO2 and carbon black particles emitted from industrial chimney were monitored by ultraviolet cameras simultaneously. A high time and spatial resolution was provided with dual-channel ultraviolet imaging remote sensing monitoring in this experiment, and the measurement results are accurate and intuitive. This method has obvious technical advantages and great application prospects in remote sensing of industrial exhaust, ship exhaust and volcanic eruption pollutions..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0404002 (2020)
Fiber Optics and Optical Communications
Photonic Crystal Fiber Temperature and Pressure Sensor
Tian-mu LIU, Yi JIANG, and Yang CUI
An hybride optical fiber sensor is presented for the measurement of temperature and pressure in high temperature environment. The sensor is based on the configuration of an extrinsic Fabry-Perot interferometer(EFPI), which is formed by a Hollow Core Fiber(HCF) sandwiched between a section of Single Mode Fiber(SMF) and An hybride optical fiber sensor is presented for the measurement of temperature and pressure in high temperature environment. The sensor is based on the configuration of an extrinsic Fabry-Perot interferometer(EFPI), which is formed by a Hollow Core Fiber(HCF) sandwiched between a section of Single Mode Fiber(SMF) and a section of of Photonic Crystal Fiber(PCF), and an intrinsic Fabry-Perot Interferometer(IFPI), which is formed by a section of PCF. Temperature measurement is achieved by thermal expansion effect and thermooptic effect, while pressure measurement is realized by the change of refractive index of gas. The demodulation of the sensor was realized by a self-made white light interferometry demodulator. In the environment of different temperature and pressure, the temperature and pressure optical fiber sensors whose cavity length is 306 μm and 1 535 μm were measured continuously. The experimental results show that the pressure sensitivity decreased with the increase of temperature. 1 460.5 nm/MPa is achieved at the temperature of 28 ℃ and the temperature response of the EFPI cavity is 17.4 nm/℃. The sensor is able to operate stably at temperature of 28~800 ℃ and pressure of 0~10 MPa..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0406001 (2020)
Photonic Generation of Filterless Frequency Multiple Tupling Optical Millimeter-wave Signal
Zhuang-zhuang XUE, Li PEI, Ting-ting LIU, Yu-heng XIE, and Jing LI
A scheme is proposed for millimeter-wave signal generation without filters. No optical or electrical filters are used in the scheme, and the scheme can obtain 16-tupling millimeter-wave signals. The scheme adopts the structure of cascading a three-parallel Mach-Zehnder modulator structure and a single Mach-Zehnder moduA scheme is proposed for millimeter-wave signal generation without filters. No optical or electrical filters are used in the scheme, and the scheme can obtain 16-tupling millimeter-wave signals. The scheme adopts the structure of cascading a three-parallel Mach-Zehnder modulator structure and a single Mach-Zehnder modulator. All redundant sidebands can be suppressed very well by adjusting the parameters of the system and only 8th order optical sidebands are left. The scheme can obtain 16-tupling millimeter-wave signals without any optical or electrical filters. The theoretical analysis for this proposed scheme are provided, and the effects of modulation depth, extinction ratio, phase shifter offset and modulator bias on the system are verified by simulation. The 10 GHz radio frequency signal is mixed with the 2 Gbit/s non-return-to-zero pattern data as the driving signal of the Mach-Zehnder modulator, it is verified that the power cost of the system link through 50 km optical fiber transmission is only 1.0 dB. The system can meet the needs of communication systems with good transmission performance. The scheme has certain reference value for the generation of high frequency millimeter wave signal without filters..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0406002 (2020)
Alignment Control Algorithm of Underwater LD Communication Based on EKF
Hao LIU, Yi YANG, Ya-fang YIN, Jian-lei ZHANG, and Si-jing LI
It is difficult to make receiver locating in the center of the light spot for high-speed laser communication, which results in difficultly establishing a stable underwater optical communication links. Monte Carlo simulation statistics method is used to analyze the distribution of the received light intensity of laser pIt is difficult to make receiver locating in the center of the light spot for high-speed laser communication, which results in difficultly establishing a stable underwater optical communication links. Monte Carlo simulation statistics method is used to analyze the distribution of the received light intensity of laser photons transmitted in seawater, and then the light spot image at the receiving end is sampled and analyzed through experiments, and the relationship between the receiver position and the received light intensity is obtained by curve fitting. The simulation and experimental results show that the received light intensity distribution is still approximately Gaussian distribution after 25 m underwater transmission. Based on the nonlinear estimation algorithm (extended Kalman filter) under the basic state control feedback theory, the distance between current position and position of the maximum light intensity spot is estimated according to received light intensity, and active tracking alignment between the receiver and the spot center is achieved by feedback algorithm. The simulation results show that the alignment error of the receiving end is less than 2 mm and the receiving efficiency is more than 98% after alignment..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0406003 (2020)
Image Processing
Infrared and Low-light-level Visible Light Enhancement Image Fusion Method Based on Latent Low-rank Representation and Composite Filtering
Ze-tao JIANG, Qi JIANG, Yong-song HUANG, and Shao-qin ZHANG
Due to the problems of low brightness and contrast, lack of detail contour information and poor visibility in the traditional infrared and low-light visible image fusion algorithm, an infrared and low-light visible enhancement image fusion method based on potential low-rank representation and composite filtering is proDue to the problems of low brightness and contrast, lack of detail contour information and poor visibility in the traditional infrared and low-light visible image fusion algorithm, an infrared and low-light visible enhancement image fusion method based on potential low-rank representation and composite filtering is proposed. Firstly, the improved high-dynamic-range compression enhancement method is used to enhance the brightness of low-light visible images. Secondly, the infrared and enhanced low-light visible images are respectively decomposed by using a decomposition method based on latent low-rank representation and composite filtering, and the corresponding low-frequency and high-frequency layers are obtained. Then, the improved contrast-enhanced visual-saliency-map fusion method and improved weighted least squares optimization fusion method are used to fuse the obtained low-frequency and high-frequency layers respectively. Finally, the low-frequency and high-frequency fusion layers are linearly superposed to obtain the final fusion image. Compared with other methods, the experimental results show that the fused image obtained by the proposed method has abundant detail information, high clarity and good visibility..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0410001 (2020)
Multiple-image Encryption Based on Image Recombination and Bit Scrambling
Yuan GUO, Yan-yan ZHOU, and Shi-wei JING
Aiming at the problems that the existing multiple-image encryption algorithms can only encrypt multiple images of the same type and the same size at the same time, which limits the scope of its application and practicality, a multiple-image encryption algorithm based on image recombination and bit scrambling was proposAiming at the problems that the existing multiple-image encryption algorithms can only encrypt multiple images of the same type and the same size at the same time, which limits the scope of its application and practicality, a multiple-image encryption algorithm based on image recombination and bit scrambling was proposed. By recombining the images of any number, any type and any size into the new multiple-gray scale images, the algorithm can complete simultaneous encryption at one time, which greatly improved the encryption efficiency and application range. Firstly, the pixel values of all images were extracted to be encrypted in turn and were recombined into N new gray-scale images of m×n size, which were converted into m×n×8N binary matrix next. Then, 3D bit scrambling is adopted to scramble rows and columns for high binary pages and the entire pages for low binary pages. Finally, the ciphertext image was obtained by XOR diffusion operation. The high-low separate scrambling improves the anti-noise ability of the algorithm. The information entropy of the final ciphertext was above 7.999, which well covered up the statistical characteristics of the plaintext. A new type of Logistic-Fibonacci cascade chaos was constructed to generate random sequences, which increased the range of initial values and control parameters, expanded the key space to over 8×1084, and greatly improve the ability to resist exhaustive attacks. The randomness of the sequence was improved, while the rapidity of the low-dimensional chaotic system was preserved. Combining with the plaintext hash value (SHA-256) to generate the key, the change rate of the ciphertext pixel value reached more than 0.996 after the plaintext pixel value was slightly changed, which greatly improved the sensitivity of the plaintext and the ability of resisting the selective plaintext attack. Experimental analysis show that the proposed multiple-image encryption algorithm has high security and strong practicability..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0410002 (2020)
Infrared Image Enhancement Based on Retinex and Probability Nonlocal Means Filtering
Jia LI, Shao-juan LI, Xiao-hu DUAN, Yuan YAO, Ji-yang LI, and Li-zhi WANG
Aiming at the problem of over enhancement and low detailed in traditional image enhancement algorithm, an infrared image enhancement method based on Retinex theory and probability nonlocal mean is proposed. Firstly, the grayscale in deep dark and bright parts of image is adjusted by the single scale Retinex method. TheAiming at the problem of over enhancement and low detailed in traditional image enhancement algorithm, an infrared image enhancement method based on Retinex theory and probability nonlocal mean is proposed. Firstly, the grayscale in deep dark and bright parts of image is adjusted by the single scale Retinex method. Then the image is decomposed into basic level and detail level by probability nonlocal mean filtering. For the basic layer, histogram equalization is used to stretch contrast, and the nonlinear function is used to enhance details for the detail layer. Finally, the different levels of the enhancement results are fused to obtain the infrared image with the contrast and detail enhanced. The simulated experiments on infrared images of different scenes are carried out through the proposed method. And the results are compared with those of different enhancement algorithms on the subjective and objective sides. The comparisons demonstrate that proposed method has better results in detail and contrast enhancement of infrared image..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0410003 (2020)
Hyperspectral Image Classification Based on Hierarchical Guidance Filtering and Nearest Regularized Subspace
Dong-dong XU, De-qiang CHENG, Liang-liang CHEN, Qi-qi KOU, and Shou-feng TANG
Aiming at the problems of low classification accuracy caused by the phenomenon that homogeneous pixels have different spectrum in the hyperspectral image and the characteristics of edge pixels being easily confused when combining spatial and spectral information, a method based on hierarchical guidance filtering and neAiming at the problems of low classification accuracy caused by the phenomenon that homogeneous pixels have different spectrum in the hyperspectral image and the characteristics of edge pixels being easily confused when combining spatial and spectral information, a method based on hierarchical guidance filtering and nearest regularized subspace is proposed in this paper. Firstly, the principal component of the hyperspectral image is obtained by principal component analysis, and then the hierarchical guidance filtering is performed with the guidance image, the first principal component. The edge-preserving characteristic of the guided filtering, effectively prevents the mixing of spectral information in edge area, and reduces the difference of the homogeneous spectrum at local regions. Finally, the nearest regularized subspace classifier is applied to classify the preprocessed hyperspectral image. Compared with the existing methods on Indian Pines, Salinas and GRSS_DFC_2013 hyperspectral datasets, the results show that the method proposed in this paper has achieved overall classification accuracy of 98.63%, 99.13% and 99.42% on the three datasets respectively, with better classification accuracy and visualization..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 49, Issue 4, 0410004 (2020)
Center Based Model for Arbitrary-oriented Ship Detection in Remote Sensing Images
Xiao-han ZHANG, Li-bo YAO, Ya-fei LÜ, Peng HAN, and Jian-wei LI
The recent proposed deep learning-based arbitrary-oriented objects detection algorithms increase extra computation burden and could not work efficiently. A one-stage model based on object centers detection is proposed for arbitrary-oriented ship detection. As the centers of objects are free from the influence their disThe recent proposed deep learning-based arbitrary-oriented objects detection algorithms increase extra computation burden and could not work efficiently. A one-stage model based on object centers detection is proposed for arbitrary-oriented ship detection. As the centers of objects are free from the influence their distribution directions, the key of the model is to regress the parameters of object's oriented bounding box on the basis of center detection. Firstly, a feature extracting network is designed to achieve feature map and a new feature fusion method is proposed which aggregates the low-level features rich in detailing information and high-level features rich in semantic information together. Then the feature map is entered to three detection branches, which predict of centers, offsets of centers, and size and direction of the oriented bounding boxes respectively. A combined loss function is proposed for the training of the network, and a modified non-maximum suppression algorithm is proposed for removing invalid oriented bounding boxes. The proposed model achieves state-of-art performance in public SAR ship detection dataset with mean average precision as 0.906, outstanding than other methods both in speed and precision..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 49, Issue 4, 0410005 (2020)
Restoration Method of Atomic Force Microscopy Image Based on Transfer Learning
Jia-cheng HU, Di-xin YAN, Yu-shu SHI, Lu HUANG, and Dong-sheng LI
Due to the structure size of the atomic force microscope probe tip, image edge distortion will occur when micro-nano measurement is performed. Thus, a blind restoration method of atomic force microscopy image based on transfer learning is proposed, where the blind restoration for the one-dimensional raster image can beDue to the structure size of the atomic force microscope probe tip, image edge distortion will occur when micro-nano measurement is performed. Thus, a blind restoration method of atomic force microscopy image based on transfer learning is proposed, where the blind restoration for the one-dimensional raster image can be realized by training sourcing model and target model. This method uses the corrosion algorithm of mathematical morphology to generate grid training samples, extracts the characteristic vectors of the convolution effect from the samples by applying the U-Net network source model, where the weight parameters are migrated to the U-Net network target model. Then the source model can conduct supervised learning under adaptive regularization method. The experimental results show that the proposed method can effectively restore the atomic force microscopy measurement image of one-dimensional grid, improve the lateral resolution, and be used in the linewidth detection of nano grid..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 49, Issue 4, 0410006 (2020)
Imaging Systems
An Improved Apparent Distance Model for Direct-viewlow-light-level Night Vision System
Wei-qi JIN, Qin ZHANG, Xia WANG, Li LI, and Su QIU
There is no difference in the evaluation of the direct-view low-light-level night vision system for the three-generation and super-second generation image intensifiers. The simulation results are not ideal under the ultra-low illumination of 10-4 lx. Therefore, three optimizations were made for the model: the transfer There is no difference in the evaluation of the direct-view low-light-level night vision system for the three-generation and super-second generation image intensifiers. The simulation results are not ideal under the ultra-low illumination of 10-4 lx. Therefore, three optimizations were made for the model: the transfer function of the human eye was added into the transfer function model of the system; the average photoelectron number and photoelectron contrast formula generated by the scene at the photocathode were corrected based on the spectral matching between the scene and the photocathode; the background noise term was added to the noise source. The improved apparent distance model was verified by the experimental results of the helmet system in field conditions. The results show that the improved model can effectively distinguish the difference between the recognition distances of the super-second generation and three-generation night vision systems, the calculation results are closer to the actual measurement results..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0411001 (2020)
Deviation Correction of Laser Scanning Projection Image Based on Time Compensation
Mao-sheng HOU, Yu-qing CHEN, Da-li LIU, Ming-li SUN, Zheng-xue SHI, and Li-juan LI
The accuracy of projected patterning is seriously influenced by several problems in practice, such as tailing, missing and corner deviations. In order to solve the above mentioned problem based on the self-developed laser scanning projection set-up, the causes of tailing, missing and corner deviation are theoretically The accuracy of projected patterning is seriously influenced by several problems in practice, such as tailing, missing and corner deviations. In order to solve the above mentioned problem based on the self-developed laser scanning projection set-up, the causes of tailing, missing and corner deviation are theoretically analyzed, then, the correction method of projection patterning deviation is studied based on time-compensated technology. Furthermore, the relationship between compensation time and sampling rate is obtained, and the mathematical model between compensation time and angle of projected patterning is established. Finally, the studied method is applied to the self-developed set-up of laser scanning projection, and the actual projected patterning are compared with the patterning which is projected by the FARO laser scanning projection system. The results show that the method can effectively eliminates the tailing and missing deviations, can compensate the corner deviation satisfactorily when projected checkerboard patterning with 5 rows and 5 columns. Compared the projected patterning before and after compensation for deviation, the accuracy of projection patterning is better than 0.5 mm. The studied method can improve accuracy of projected patterning significantly when applied to the self-developed set-up of laser scanning projection. Moreover, the studied method has good value for practical application..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0411002 (2020)
Multi-resolution Imaging with Camera Arrays on Curved Surface
Jie CAO, Huan CUI, Ling-tong MENG, Qun HAO, and Ming-yuan TANG
Based on the variable resolution mechanism of human retina and the imaging principle of parallel compound eye, a hybrid bionic imaging system with multi-resolution is proposed to reduce data redundancy and to balance large field of view, high resolution and high efficiency. Given the consideration of both curved and plBased on the variable resolution mechanism of human retina and the imaging principle of parallel compound eye, a hybrid bionic imaging system with multi-resolution is proposed to reduce data redundancy and to balance large field of view, high resolution and high efficiency. Given the consideration of both curved and plane surface on the layout, the imaging system included three layers in which the eleven cameras are divided into four groups to obtain images with four different resolutions. Two imaging experiments under the conditions of long distance of 100 m and short distance of 10 m are carried out, the results indicate that the total field of view reaches 150.8°×37.8° as keeping high resolution in the fovea. Moreover, the results of multi-resolution imaging experiments show that the system reduces the image resolution from the central field of view to the edge field of view gradually, and the amount of stitched image data with four-level resolution is reduced 17.2 times of data redundancy compared to the high-resolution image with total field of view..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0411003 (2020)
Instrumentation, Measurement and Metrology
A Specular Stepped Surface Profile Measurement System Based on Fringe Reflection Principle with Micrometer-level Height Resolution
Xin-jun WAN, Song LÜ, Ke SONG, and Shu-ping XIE
A fringe reflection three dimensional (3D) profile measurement system is proposed for micrometer-level height stepped mirrors. A systematic theoretical analysis of fringe reflection ray path is conducted, showing that by proper selection of the structure parameters including the ray incident angle, the Liquid Crystal DA fringe reflection three dimensional (3D) profile measurement system is proposed for micrometer-level height stepped mirrors. A systematic theoretical analysis of fringe reflection ray path is conducted, showing that by proper selection of the structure parameters including the ray incident angle, the Liquid Crystal Display(LCD) screen orientation angle and the LCD screen pixel size, the fringe reflection system can resolve micron and even sub-micron level stepped mirrors. A micrometer-level resolution fringe reflection measurement setup for stepped mirrors is constructed, which calculates the fringe phase using the four-step phase shift method, determines the reflected light equation using the moving screen method and reconstructs the 3D shape based on triangulation method. A stepped mirror sample with 5 μm and 10 μm steps is finally measured. The measurement uncertainty is within 0.5 μm and the discrepancy with the commercial system result is less than 0.5 μm, which proves the feasibility of the designing method. The result of this paper can be of great reference to the 3D reconstruction study of specular surfaces with diffractive structures..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 49, Issue 4, 0412001 (2020)
Specular Normal Calibration Technology of Point Source
Rui-jin LI, Li-ming ZHANG, Xin LI, Wei WANG, Jia-wei LI, and Jun HAO
In the process of on-orbit radiation calibration, based on reflective point light sources, the modeling of specular normal calibration is inadequate. Aiming at this problem, a specular normal calibration and vector control algorithm based on reflector and camera geometry model is presented. The geometrical placement erIn the process of on-orbit radiation calibration, based on reflective point light sources, the modeling of specular normal calibration is inadequate. Aiming at this problem, a specular normal calibration and vector control algorithm based on reflector and camera geometry model is presented. The geometrical placement error between the camera and the reflector is solved by solving the model. The relationship between the centroid coordinates of the solar image and the normal direction of the reflector is established. The multi-point automatic calibration of the specular normal is realized. The method improves the pointing accuracy of the system and specular normal calibration accuracy. The experiment results show that the geometric model anti-solves the centroid coordinates at different times, which for multi-point specular normal calibration. The standard errors of the angular resolution of the sun pixels observed by the camera are 0.021 65° in the X-axis direction and 0.019 82° in the Y-axis direction. The error of the synthetic angle resolution is 0.029 36 °. The accuracy of calibration is better than that of the solar observer to the specular normal calibration. The method realizes the automatic calibration process of the camera observing the solar image instead of manually observing, and expands calibration flexibility. Comprehensive pointing accuracy of system is better than 0.1°. It lays the foundation for on-orbit radiation calibration and modulation transfer function detection of point light source array of networking automation of fixed experimental sites centrally control different energy levels gradients..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 49, Issue 4, 0412002 (2020)
Lasers and Laser Optics
State-switchable Multi-wavelength and Dissipative Soliton Mode-locked Tm-doped Fiber Laser Based on a Combination of Nonlinear Amplifying Loop Mirror and Lyot Filter
Xiao-fa WANG, Jing-hui LIU, and Zeng-gao JIN
This paper demonstrates a state-switchable Tm-doped fiber laser based on nonlinear amplifying loop mirror and Lyot filter technique. By properly adjusting the polarization controller and pump power, the Tm-doped fiber laser can operate in multi-wavelength state and dissipative soliton mode-locked state, respectively. AThis paper demonstrates a state-switchable Tm-doped fiber laser based on nonlinear amplifying loop mirror and Lyot filter technique. By properly adjusting the polarization controller and pump power, the Tm-doped fiber laser can operate in multi-wavelength state and dissipative soliton mode-locked state, respectively. And two types of operating states can be switched to each other. For multi-wavelength state, 8 stable wavelength peaks are generated within half of peak power variation. For the dissipative soliton mode-locked state, the dissipative soliton with pulse energy as high as 41.49 nJ, the pulse duration of 2.4 ns, and the spectrum bandwidth of 29 nm is generated at the center wavelength of 1 996 nm. The switching between different operating states is due to the change in the function of the nonlinear amplifying loop mirror caused by the polarization controller..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0414001 (2020)
Research on Heat Transfer Characteristics of Porous Foam Heat Sink for All Solid State Thin Disk Lasers
Rui LIU, Fa-quan GONG, Xiang LI, Long-hui DAI, Gang LI, and Yong TAN
The thermal lens effect of high-power all solid state thin disk lasers in operation can cause the laser output power to decrease and the beam quality to deteriorate. In this paper, focus on this problem, porous SiC foam and millimeter channels are introduced into the heat transfer heat sink of the thin disk laser and aThe thermal lens effect of high-power all solid state thin disk lasers in operation can cause the laser output power to decrease and the beam quality to deteriorate. In this paper, focus on this problem, porous SiC foam and millimeter channels are introduced into the heat transfer heat sink of the thin disk laser and applied to all solid state thin disk laser. The finite element analysis software is used to optimize the structural model. And the simulation analysis indicates that, when the thickness of SiC is 2 mm, the porosity is 40% and the inlet pressure is 4 kg (0.4 MPa), the theoretical heat transfer coefficient is 1.51×105 W/m2·K, the experimental heat transfer coefficient is 1.45×105 W/m2·K, the results are similar to each other, which verifies the correctness of the theoretical model. Finally, the new heat sink is used to build a 24 multi-passes all solid state thin disk lasers experimental device based on Yb:YAG. The continuous laser output with output power of 393 W and wavelength of 1 030 nm is obtained, the optical-optical efficiency is 52% and the beam product parameter is 5.918 mm·mrad..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0414002 (2020)
Experimental Research on Power-balanced Nd:YVO4/Nd:GdVO4 Dual-wavelength Laser
Meng-ying XIA, Miao HU, Hui-min ZHOU, Zheng-feng QIAN, Xue-fang ZHOU, Guo-wei YANG, Yang LU, and Mei-hua BI
The output characteristics of the power-balanced Nd:YVO4/Nd:GdVO4 Dual-Wavelength Laser (DWL) under different pumping conditions is investigated experimentally. The experimental results show for power-balanced Nd:YVO4/Nd:GdVO4 DWL, the heat sink temperature needs reduce when the pumping power increases, and the ratio oThe output characteristics of the power-balanced Nd:YVO4/Nd:GdVO4 Dual-Wavelength Laser (DWL) under different pumping conditions is investigated experimentally. The experimental results show for power-balanced Nd:YVO4/Nd:GdVO4 DWL, the heat sink temperature needs reduce when the pumping power increases, and the ratio of temperature decreasing versus pumping power increasing is 11.23 ℃/W. With the change of pumping power and heat sink temperature, the DWL wavelengths shift slightly. When the pumping power increases, the DWL left wavelength blue-shifting rate is 0.056 nm/W, and the right wavelength one is 0.054 nm/W. The result also found that the output power of the power-balanced DWL increases with the pumping power increasing. The fitted slope efficiency is 8.7%. When the pumping power is 5.58 W, the maximum output power reaches 115.7 mW..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0414003 (2020)
Experimental Study on Dislocation Configuration and Grain Refinement of 690 High Strength Steel Treated by Laser Shock Processing
Yu-peng CAO, Cong YANG, Wei-dong SHI, Guo-ran HUA, Bin LI, and Rong LI
In order to study the relationship between dislocation configuration and grain refinement in materials treated by laser shock processing, 690 high-strength steel was impact-strengthened by pulsed laser. The scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscoIn order to study the relationship between dislocation configuration and grain refinement in materials treated by laser shock processing, 690 high-strength steel was impact-strengthened by pulsed laser. The scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy images of the sample treated by laser shock processing were obtained using scanning electron microscopy and transmission electron microscopy. The inverse fast Fourier transform was performed on the high resolution transmission electron microscopy image, and a grain refinement model of 690 high strength steel treated by laser shock processing was established from the perspective of dislocation configuration. The results show that after the 690 high-strength steel was loaded by laser shock with a power density of 5.09 GW/cm2, the internal dislocations of the material are proliferated and the surface grains are refined, with grain size ranging between 80 nm and 200 nm (cross section). The precipitation phase maintains a semi-coherent relationship with the matrix, and many defects such as edge dislocations, dislocation couples and extended dislocations are distributed in the matrix, among which the dislocation couples are formed by the screw dislocation motion with cut order. The geometrical dislocation interfaces' extension and intersection divides the original large crystal grains into fine grains, which consists of dislocations, extended dislocations, vacancies, etc.The grain refinement model of 690 high strength steel treated by laser shock processing can describe the grain refinement process dominated by the dislocation movement of 690 high strength steel..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0414004 (2020)
Machine Vision
Point Cloud Registration Based on Neighborhood Characteristic Point Extraction and Matching
Xin-chun LI, Zhen-yu YAN, Sen LIN, and Di JIA
In order to solve the problem of poor robustness and low registration accuracy of the iterative closest point algorithm under noise interference and data loss, a point cloud registration method based on neighborhood characteristic point extraction and matching is proposed. Firstly, a neighborhood characteristic parametIn order to solve the problem of poor robustness and low registration accuracy of the iterative closest point algorithm under noise interference and data loss, a point cloud registration method based on neighborhood characteristic point extraction and matching is proposed. Firstly, a neighborhood characteristic parameter is defined, which is composed of three parts: the k-neighborhood curvature of the point, the normal vector inner product' mean value of the point and the neighborhood points, and the distance variance between the neighborhood points and the neighborhood fitted plane. Neighborhood characteristic parameters and curvature characteristic parameters constructed on moving least square surface are used to extract feature points twice. Secondly, three matching conditions are defined according to the histogram features, and the correct matching point pairs are obtained by double constraints. Finally, in the registration stage, the iterative closest point algorithm of bi-directional k-dimension tree is used to achieve accurate registration. The experimental results show that the registration accuracy of the proposed algorithm is more than 90% higher than that of the iterative closest point algorithm, and it can effectively complete the registration of missing point clouds in noisy environment, which has obvious advantages in robustness and precise registration..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 49, Issue 4, 0415001 (2020)
Optical Devices
Near-infrared Properties of Optical Planar Waveguides Formed by H+ Ion Implantation in Yb3+-doped Phosphate Glasses
Jing-yan LÜ, Hai-tao GUO, Jun XU, and Chun-xiao LIU
The Yb3+-doped phosphate glass waveguides by the hydrogen-ion implantation under the condition of energies of (0.5+0.55) MeV and doses of (1.0+2.0)×1016 ions/cm2 were fabricated, and characteristics of the waveguide were studied in the near-infrared band. The change of refractive index after the implantation was mThe Yb3+-doped phosphate glass waveguides by the hydrogen-ion implantation under the condition of energies of (0.5+0.55) MeV and doses of (1.0+2.0)×1016 ions/cm2 were fabricated, and characteristics of the waveguide were studied in the near-infrared band. The change of refractive index after the implantation was measured by the prism coupling method, which corresponded well with the calculated effective refractive index by the reflectivity calculation method. The formation theory of the ion-implanted planar waveguides was discussed through simulating the vacancy distribution induced by the irradiation. The propagation mode of light in the waveguide was simulated by using the FD-BPM, which suggested that the near-infrared waveguide structure could be fabricated by irradiating the Yb3+-doped phosphate glass with the energetic hydrogen ions..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0423001 (2020)
Orthogonal Phase Detection Method of Light-addressable Potentiometric Sensor
Xing-yuan TONG, Xiao-guang YAN, and Dong CHEN
The amplitude detection method of the Light-Addressable Potential Sensor (LAPS) is susceptible to noise interference, low sensitivity, low precision, low signal-to-noise ratio, and is greatly affected by the modulated light signal, which affects the accuracy of the detection results. Therefore, a LAPS detection method The amplitude detection method of the Light-Addressable Potential Sensor (LAPS) is susceptible to noise interference, low sensitivity, low precision, low signal-to-noise ratio, and is greatly affected by the modulated light signal, which affects the accuracy of the detection results. Therefore, a LAPS detection method based on orthogonal phase detection is proposed. In this method, the LAPS photocurrent signal is multiplied by two orthogonal signals, and the direct current component is extracted by low-pass filters and divided, so that the phase information of LAPS photocurrent signal can be obtained. Compared with the existing LAPS phase detection method, the proposed method has the advantages of low algorithm complexity and high real-time performance. The influence of the modulated light intensity on the amplitude detection and phase detection of LAPS is studied. The sensitivity, linearity and signal-to-noise ratio of the conventional amplitude detection method and the orthogonal phase detection method of LAPS to the detection of pH are compared. The results show that, compared with the amplitude detection method, the modulated light intensity has less effect on the phase detection of LAPS. When the frequency at 10 kHz, the pH is from 1.68 to 10.01, the sensitivity of the phase detection method is increased by 7 mV/pH, the precision accuracy is increased by 14.9 mpH, the nonlinear error is reduced by 0.003%, the mean square error is reduced by 0.105 1×10-5, the signal-to-noise ratio is increased by 8.2827. The proposed method is especially suitable for LAPS detection in weak modulated light intensity..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0423002 (2020)
Physical Optics
Interaction of Dark Rogue Waves
Ren GAO, Juan-fen WANG, Xuan ZHANG, Ling-zhen YANG, and Zhao-xia ZHANG
The coupled nonlinear Schr?dinger equation was used as a theoretical model to study the interaction of two first-order dark rogue waves in a normal dispersion single-mode fiber. Based on the exact solution of first-order dark rogue wave, the interaction between two adjacent first-order dark rogue waves is discussed in The coupled nonlinear Schr?dinger equation was used as a theoretical model to study the interaction of two first-order dark rogue waves in a normal dispersion single-mode fiber. Based on the exact solution of first-order dark rogue wave, the interaction between two adjacent first-order dark rogue waves is discussed in terms of spacing, phase and ratio of amplitude coefficients using split-step Fourier numerical simulation. Based on the exact solution of the second-order dark rogue wave, the nonlinear interaction of two first-order dark rogue waves is discussed.The results show that the interaction of two adjacent in-phase first-order dark rogue waves will generate "twisted" dark rogue waves when the interval parameter T1 is 0, 5, 20. Compared to the energy diffusion of a single dark rogue wave, the "twisted" dark rogue wave can split and form multiple secondary dark rogue waves.In the case of out of-phase, when the interval parameter T1 is 2, 7, 12, the interaction of two adjacent first-order dark rogue waves can also stimulate and generatethe "twisted" dark rogue waves. And the initially excited spatial position of the "twisted" dark rogue wave deviates from that of the original single dark rogue wave.The larger the ratio of amplitude coefficients, the closer this spatial position is to 5.Second-order dark rogue waves can be regarded as the nonlinear superposition of two first-order dark rogue waves.The composite and three-component second-order dark rogue waves are slightly similar to the interaction between two adjacent first-order dark rogue waves..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0426001 (2020)
Tightly Focusing Property of Off-axial Vector Beams
Yu LI, Peng LI, Dong-jing WU, and Jian-lin ZHAO
The tightly focusing property of vector beams with off-axial polarization singularities are numerically investigated, according to the Richard-Wolf vector diffraction intergation theory. A method for designing speical focal field is proposed, based on the tightly focusing of vector field with generalized polarization dThe tightly focusing property of vector beams with off-axial polarization singularities are numerically investigated, according to the Richard-Wolf vector diffraction intergation theory. A method for designing speical focal field is proposed, based on the tightly focusing of vector field with generalized polarization distribution, after analyzing the tightly focusing of radially and azimuthally polarized beams. Moreover, the modulation effect of symmetric broken of off-axial polarization singularites on the focused field, especially the modulation effect on the Spin Angular Momentum (SAM) density, are discussed by analyzing the variation of SAM distributions arising from spin-orbital coupling. The results not only rich the tightly focusing property of vector beam, but also provide reference for improving the distribution of focal field..
Acta Photonica Sinica
- Publication Date: Apr. 25, 2020
- Vol. 49, Issue 4, 0426002 (2020)
Quantum Optics
Non-classical Properties of Laguerre Polynomial's Photon Added Coherent State
Dao-ming LU
Laguerre polynomial's photon added coherent state is constructed by operation of Laguerre polynomial's photon added operator on coherent state. By the technique of integration within an ordered product of operators, its normalization factor and the calculation expression of 〈ala+m〉 are derived. The influences oLaguerre polynomial's photon added coherent state is constructed by operation of Laguerre polynomial's photon added operator on coherent state. By the technique of integration within an ordered product of operators, its normalization factor and the calculation expression of 〈ala+m〉 are derived. The influences of the phase angle and the average photon number of coherent state on its non-classical properties are discussed. Numerical results show that, the first-order Laguerre polynomial's photon added coherent state presents squeezing effect, anti-bunching effect, sub-Poissonian statistical property and negativity of Wigner function, and the phase angle of the coherent state has an important influence on its quantum properties. On the other hand, its anti-bunching effect is weakened with the increase of the average photon number of coherent state, and so is the sub-Poissonian distribution property. However, its squeezing property and the negativity of Wigner function are firstly enhanced and then gradually weakened with the increase of the average photon number of coherent state..
Acta Photonica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 49, Issue 4, 0427001 (2020)
© Copyright 2018-2021 | Chinese Laser Press. All Rights Reserved 沪ICP备15018463号-20