Contents
2017
Volume: 37 Issue 6
45 Article(s)
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Versatile Electrostatic Well for Trapping Cold Polar Molecules on Chip Surface
Li Shengqiang
An electrostatic surface well scheme for trapping cold polar molecules in week-field-seeking state is proposed, and the electrostatic surface well is composed of a pair of metallic parallel-plate capacitors and four charged rods part-embedded in insulating medium. Spatial distribution of electric field is calculated wiAn electrostatic surface well scheme for trapping cold polar molecules in week-field-seeking state is proposed, and the electrostatic surface well is composed of a pair of metallic parallel-plate capacitors and four charged rods part-embedded in insulating medium. Spatial distribution of electric field is calculated with the finite element software in the trapping process in the case of single well trapping, and we find that a three-dimensional enclosed electrostatic well which is 2.2 mm above the chip surface is obtained. Ammonia molecule (ND3) is chosen as the test molecule and the dynamic processes of loading and trapping are simulated by the classical Monte Carlo method. Simulation results indicate that when the velocity of ND3 molecular beam center is 13 m/s and the loading time is 0.576 ms, the loading efficiency as high as 53% can be obtained, and the corresponding temperature of trapping cold molecules is about 35 mK. When the voltage applied to the flat electrode is increasing, the single well will splits into two symmetrical wells, and the ratio of the molecules in the two wells is 1∶1. Unsymmetrical split of the single well can be realized when we adjust the voltages of the two pole electrodes in the middle, and the ratio of trapping molecules in the two wells can be controlled. The ratio of molecules in the left well or the right well to the total molecules can be adjusted from 0% to 100%. This method lays a foundation for the three-dimensional trapping cold polar molecule electrostatic surface interferometer, and it is helpful for the studies about precision measurement and matter wave interference..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 602001 (2017)
Correct Astigmatism Aberration with Rotating Cylinders
Ying Rui, Zhao Junlei, Xiao Fei, Li Jinyu, Yang Chen, Zhao Haoxin, Wang Cheng, and Dai Yun
How to effectively correct ocular aberrations which vary largely from person to person and improve the application scope of adaptive optical system for human retinal imaging is the biggest problem in the clinical application. Rotating cylinders provide a flexible method to correct astigmatism at low cost. This study prHow to effectively correct ocular aberrations which vary largely from person to person and improve the application scope of adaptive optical system for human retinal imaging is the biggest problem in the clinical application. Rotating cylinders provide a flexible method to correct astigmatism at low cost. This study provides the theoretical basis of rotating cylinders for the astigmatism compensation and an experimental system of automatically correcting astigmatism is established based on the far-field facula analysis to prove the theoretical basis. Then the rotating cylinders are combined with an adaptive optics system and the real-time wavefront is measured by the Hartman-Shack sensor to guide rotating cylinders adjustment. The modified system could compensate the astigmatism aberration automatically from -4 to 0 Dc with residual error lower than 0.1 Dc. Combined with the Badal lens, this system provides an economical and effective method to compensate low aberrations for large-scale clinical applications of adaptive optical system for human retinal imaging..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 633001 (2017)
Atmospheric Optics and Oceanic Optics
Design and Validation of Parallelized Computational Model for Nonspherical Aerosol Scattering Based on Multi-Resolution Time-Domain
Hu Shuai, Gao Taichang, Li Hao, Yang Bo, Chen Ming, Liu Lei, and Li Gang
In order to decrease computational time and computer memory consumed by the serial multi-resolution time-domain (MRTD) scattering model, a parallel calculation model for nonspherical aerosol scattering is proposed based on message passing interface (MPI) technique. A basic frame of the MRTD scattering model and two parIn order to decrease computational time and computer memory consumed by the serial multi-resolution time-domain (MRTD) scattering model, a parallel calculation model for nonspherical aerosol scattering is proposed based on message passing interface (MPI) technique. A basic frame of the MRTD scattering model and two parallelization data communication schemes are introduced, and the parallel design for MRTD scattering model is achieved by MPI repeated non-blocking communication technique. A network parallel computation platform is established for the parallel calculation. To validate the computational accuracy of the MRTD scattering model, the simulation results of parallelized MRTD scattering model are compared with that of Mie scattering model and T Matrix method. The results show that the MRTD model can calculate the scattering parameters of nonspherical particles accurately. Parallel computational technique can improve computation efficiency notably. The computation efficiency of the parallelization design scheme that exchanges electric field and magnetic field simultaneously is higher than that of the scheme that exchanges magnetic field simply. With increasing the number of central processing unit cores, the parallel acceleration ratio of program is incresing, while the computational efficiency of single processor is slightly decreasing. With the increasing of particle size parameter, the computational efficiency of single processor is increasing as well. It also can be found that the change of complex refractive index has no notable influence on parallel computational efficiency..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 601001 (2017)
Lidar Data Gluing Technology Based on Hybrid Intelligent Algorithm
Duan Lulin, Liu Dong, Zhang Yupeng, Cheng Zhongtao, Luo Jing, Yang Yongying, Shen Yibing, and Bai Jian
Two-channel data gluing technology can extend the dynamic detection range of lidar system effectively and improve the signal to noise ratio of atmospheric echo signal. A lidar data gluing technology based on the non-dominated sorting genetic algorithm II (NSGA-II) and neighborhood rough set (NRS) is proposed to improveTwo-channel data gluing technology can extend the dynamic detection range of lidar system effectively and improve the signal to noise ratio of atmospheric echo signal. A lidar data gluing technology based on the non-dominated sorting genetic algorithm II (NSGA-II) and neighborhood rough set (NRS) is proposed to improve the accuracy and stability of data gluing. Three evaluation functions determining goodness of fitting are taken as objective functions and the Pareto optimal solution set is acquired by NSGA-II. The weight which is acquired by NRS is applied to accomplishing the global random searching for the best fitting range. The experimental results show that the proposed algorithm has a favorable gluing result and works steadily in gluing tasks all day..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 601002 (2017)
Full-Time Lidar System for Ultraviolet High Spectral Rayleigh Temperature Measurement
Shao Jiangfeng, Hua Dengxin, Wang Li, Wang Jun, and Yan Qing
A ultraviolet high spectral lidar for Rayleigh temperature measurement is an effective tool for detecting the temperature profile. At present, the light with wavelength of 355 nm is used in the ultraviolet high spectral lidar for Rayleigh temperature measurement. However, the solar backgroun radiation has a great influA ultraviolet high spectral lidar for Rayleigh temperature measurement is an effective tool for detecting the temperature profile. At present, the light with wavelength of 355 nm is used in the ultraviolet high spectral lidar for Rayleigh temperature measurement. However, the solar backgroun radiation has a great influence on the signal-noise ratio (SNR), and the distance and the accuracy of temperature measurement are restricted. To realize the full-time measurement for atmospheric temperature, a 266 nm ultraviolet high spectral lidar system for Rayleigh temperature measurement based on Fabry-Perot etalon is presented. Because there is no 266 nm light in the solar background radiation, the effect of ozone on the 266 nm light absorption is only needed to be considered, and then the full-time measurement for atmospheric temperature is realized. The spectral widths, transmission rates, SNR of echo signal and temperature errors of 266 nm and 355 nm ultraviolet high spectral lidar systems for Rayleigh temperature measurement are simulated and analyzed based on main parameters, such as pulse energy, diameter of telescope, receiving view field angle of telescope, concentration of ozone and solar background light intensity. Results show that the influence of atmospheric molecular and aerosol scattering on light at 266 nm is much larger than that of light at 355 nm. In the daytime, the effective measurement distance of 266 nm ultraviolet high spectral lidar system for Rayleigh temperature measurement is about 4 km, which is 2.9 km far than that of 355 nm ultraviolet high spectral lidar system for Rayleigh temperature measurement. The effective measurement distance of 266 nm ultraviolet high spectral lidar system for Rayleigh temperature measurement is about 6 km in the nighttime. When the measurement distance is smaller than 5 km, the temperature error of 266 nm ultraviolet high spectral lidar system for Rayleigh temperature measurement is 10 K less than that of 355 nm ultraviolet high spectral lidar system for Rayleigh temperature measurement in the daytime. The 266 nm ultraviolet high spectral lidar for Rayleigh temperature measurement can be used to measure atmospheric temperature in the daytime and in the nighttime..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 601003 (2017)
Low Elevation Atmospheric Refraction Correction Method Based on Gridding Atmospheric Parameter Profile Mode
Wu Pengfei, Li Yujian, Shao Shiyong, Kang Deyong, Chen Jiahong, Li Xuebin, Wei Heli, and Rao Ruizhong
High precision and low elevation atmospheric refraction correction method is an important assurance for improving omnibearing measurement ability of optic-electronic measuring and control system both in sea and land. According to the light tracing method, a low elevation atmospheric refraction correction method consideHigh precision and low elevation atmospheric refraction correction method is an important assurance for improving omnibearing measurement ability of optic-electronic measuring and control system both in sea and land. According to the light tracing method, a low elevation atmospheric refraction correction method considering inhomogeneous of atmospheric space is proposed. The error and the effect factors of the correction method are analyzed thoroughly, including the effects of atmospheric space inhomogeneous and turbulence on low elevation atmospheric refraction correction, and the maximum error of atmospheric refractivity height distribution under different refraction correction precisions is provided. The data base of the correction method is the autonomously established three-dimensional space gridding atmospheric parameter height distribution mode based on measured profile data. The refraction correction results under typical atmospheric condition are analyzed by the proposed correction method and the gridding atmospheric parameter profile mode..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 601004 (2017)
Influence of Topological Charge on Turbid Underwater Propagation of Laguerre-Gaussian Vortex Beams
Peng Bo, Zhong Kun, and Li Zhongyun
The turbid underwater propagation of Laguerre-Gaussian (LG) vortex beams is investigated experimentally with different topological charges, and Gaussian beams are used as the reference light. Results show that LG beams with large topological charge have strong underwater propagation capability when water is relatively The turbid underwater propagation of Laguerre-Gaussian (LG) vortex beams is investigated experimentally with different topological charges, and Gaussian beams are used as the reference light. Results show that LG beams with large topological charge have strong underwater propagation capability when water is relatively turbid (the attenuation length is not higher than 0.118 m). With respect to the energy density distribution of the transmission beams, the transmission distance determines the optimal topological charge, and it is independent of the water turbidity. The experimental method and measured results have potential guiding significance and engineering value for the applications of LG vortex beams in underwater optical communication, underwater target detection and other fields..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 601005 (2017)
Fiber Optics and Optical Communications
Hollow Optical Fiber Surface Plasmon Resonance Sensor Based on Light Intensity Detection
Zhang Yu, Zhu Xiaosong, and Shi Yiwei
A hollow optical fiber surface plasmon resonance (SPR) sensor based on light intensity detection is proposed. The 532 nm laser is used as the light source, and the performance of the sensor is investigated. The performance of the sensor is theoretically analyzed based on the light transmission model. Experimental resulA hollow optical fiber surface plasmon resonance (SPR) sensor based on light intensity detection is proposed. The 532 nm laser is used as the light source, and the performance of the sensor is investigated. The performance of the sensor is theoretically analyzed based on the light transmission model. Experimental results are in agreement with theoretical results. The highest sensitivity of 8380.3 μW/RIU and the optimum resolution of 5.5×10－6 RIU can be obtained by the sensor in linear region. The resolution of the proposed sensor is improved by two orders of magnitude compared to that of the hollow optical fiber SPR sensor based on wavelength detection. The experimental system is simple, and it is beneficial to miniaturization of devices..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 606001 (2017)
Image Processing
A Method for Small Infrared Targets Detection Based on the Technology of Motion Blur Recovery
Li Sijian, Fan Xiang, Zhu Bin, and Cheng Zhengdong
The motion of the infrared detection system always has a significant effect on the imaging process, resulting in the motion blur of the target image, which brings evident uncertainties and difficulties to the infrared small target detection. In order to efficiently detect the infrared small targets whose images have beThe motion of the infrared detection system always has a significant effect on the imaging process, resulting in the motion blur of the target image, which brings evident uncertainties and difficulties to the infrared small target detection. In order to efficiently detect the infrared small targets whose images have been blurred by the motion of them, the technique of motion blur restoration and image enhancement are introduced into the infrared detection system. The method firstly applies Wiener filter in the processing of original images so as to restrain the noise and reduce the motion blur, then makes the use of gradient method to sharpen and enhance the target edges of processed images. The experiment results and simulation analyses show that such method can obviously reduce motion blur, enhance the contrast of targets, and restrain noise to a certain extent, which improving images′ quality and making infrared targets prominent in the background. Finally, the evaluation parameters peak signal to noise ratio and mean square error perform well. The proposed method can enhance the effect of detective system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 610001 (2017)
Imaging Systems
Real-time Image Detection in Corneal Topography
Sui Chenghua, Han Yonghao, Xu Danyang, Gao Nan, Gao Jianxun, Wo Shengjie, and Du Chunnian
In order to realize real-time image detection in corneal topography, it is a key step to find an image sharpness evaluation function for fast, stable and accurate identification of real-time corneal images. For the optical imaging system of corneal topography, the defocusing effect on image sharpness is analyzed and a In order to realize real-time image detection in corneal topography, it is a key step to find an image sharpness evaluation function for fast, stable and accurate identification of real-time corneal images. For the optical imaging system of corneal topography, the defocusing effect on image sharpness is analyzed and a new image sharpness evaluation method is proposed. In the method, the Laplace function is selected as the coarse tuning evaluation parameter of a global image. Through Hough circle transform and sub-pixel edge detection, the center of the image is determined. With the center of the image, the clearest edge is found by the edge detection method based on the combination of Sobel operator and Canny operator. Based on that, the clearest corneal image is got in real-time. The experimental results verify that the proposed method has good stability and noise immunity, can evaluate the image sharpness accurately and effectively, and is suitable for real-time image detection in corneal topography..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 611001 (2017)
Study on the Image Information Carried by the Non-Diffraction Beam Imaging System
He Yanlin, Xu Haobo, and Wu Fengtie
The status of image information carried by the non-diffraction beam imaging system is proposed. Based on the Kirchhoff diffraction formula and Fresnel diffraction formula’s angular spectrum theory, the intensity distribution of receiving screen is described using the discrete Fourier method, with image information in tThe status of image information carried by the non-diffraction beam imaging system is proposed. Based on the Kirchhoff diffraction formula and Fresnel diffraction formula’s angular spectrum theory, the intensity distribution of receiving screen is described using the discrete Fourier method, with image information in the incident plane wave. After adding the dispersion formula and data sampling, a discrete Fourier formula is derived, the related parameters are set and simulated with Matlab software, and the light intensity figures at different positions are obtained. In the experiment, the blue LED is incident on information film and axicon after expanding, and consistent with the numerical simulations. The results observed by CCD and compared to simulation show that the image can be observed completely when the transmission distance within 100 mm and becomes smaller as the distance increases. The experimental results are in fair agreement with the numerical simulation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 611002 (2017)
Imaging Method of Downward-Looking Three-Dimensional Synthetic Aperture Radar Based on Bayesian Learning
Kang Le, Zhang Qun, Li Taoyong, and Gu Fufei
To meet the request of high resolution on cross-track, conventional downward-looking three-dimensional synthetic aperture radar (DL 3D SAR) imaging on micro unmanned aerial vehicle requires much longer transmitting antenna and more receiving antenna array. A novel imaging method of DL 3D SAR based on Lp regularization To meet the request of high resolution on cross-track, conventional downward-looking three-dimensional synthetic aperture radar (DL 3D SAR) imaging on micro unmanned aerial vehicle requires much longer transmitting antenna and more receiving antenna array. A novel imaging method of DL 3D SAR based on Lp regularization is proposed. Analyzing the 3D echo signal model, the over-complete dictionary is structured. And the imaging problem is transformed into a Lp regularization model which can be solved by sparse Bayesian learning method. The simulation results show that the proposed method can cut down nearly 3/4 length of antenna array without reducing the imaging quality obviously, or make the cross-track resolution improve 2 times with full sampling compared to the conventional method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 611003 (2017)
Fast Reflective Scanning Imaging Based on Terahertz Quantum-Cascade Laser
Li Mengqi, Tan Zhiyong, Qiu Fucheng, Wan Wenjian, Wang Chang, and Cao Juncheng
A fast reflective scanning imaging system is constructed by employing the terahertz (THz) quantum-cascade laser as the light source and the low-temperature bolometer as the signal receiver. A rotational and translational platform is used in this imaging system to realize fast scanning. The fast imaging process of a cirA fast reflective scanning imaging system is constructed by employing the terahertz (THz) quantum-cascade laser as the light source and the low-temperature bolometer as the signal receiver. A rotational and translational platform is used in this imaging system to realize fast scanning. The fast imaging process of a circle area with a diameter of 80 mm is demonstrated by a computer controlling the scanning platform to carry out the rotational and translational motion. The signal intensity and the related 2D sample position are acquired simultaneously. By the imaging system, the scanning time is 5 s and the spatial resolution of the obtained image is 1 mm, which greatly shortens the imaging time. Furthermore, the optical components are reduced effectively by the co-optical path design based on THz beam splitters, which reduces the size of the THz imaging system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 611004 (2017)
Instrumentation, Measurement and Metrology
Study for Signal-to-Noise Ratio of Spatial Heterodyne Spectrometer
Luo Haiyan, Xiong Wei, Shi Hailiang, and Li Zhiwei
The general expression about signal-to-noise ratio ( SNR ) in spatial domain and spectral domain of spatial heterodyne spectrometer is deduced considering the primary noise, and the relationship between SNR and instrumental characteristic parameter is analyzed, which includes spectral resolution, spatial resolution, deThe general expression about signal-to-noise ratio ( SNR ) in spatial domain and spectral domain of spatial heterodyne spectrometer is deduced considering the primary noise, and the relationship between SNR and instrumental characteristic parameter is analyzed, which includes spectral resolution, spatial resolution, degree of interferogram modulation, electronics noise and so on. Combined instrumental characteristic parameter with imaging methods mode, the corresponding conclusion is obtained , and the results show that SNR can efficiently evaluate and reflect the character of spectrometer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 612001 (2017)
Design and Performance Test of Gershun Tube Spectral Radiometer
Wang Xiaoxu, and Li Zhigang
To meet the application requirements of terrestrial/space radiometric calibration and solar/atmospheric remote sensing measurement, a high precision spectral radiometer based on Gershun tube is developed. A design for Gershun tube spectral radiometer is introduced, and the spectral responsivity, spatial response uniforTo meet the application requirements of terrestrial/space radiometric calibration and solar/atmospheric remote sensing measurement, a high precision spectral radiometer based on Gershun tube is developed. A design for Gershun tube spectral radiometer is introduced, and the spectral responsivity, spatial response uniformity, angular response property and inside and outside field-of-view radiation response characteristic of the Gershun tube spectral radiometer are tested. The Gershun tube spectral radiometers based on detector standard and spectral irradiation source standard are compared, and the standard uncertainty range is analyzed. Experimental results show that the spectral response repeatability of the Gershun tube spectral radiometer is 0.3%, the regional responsivity uniformity is 0.3%, the consistency of angular response and expected cosine distribution is 0.2%, and the radiation suppression ability outside field-of-view is 2.1×10-4. Standard uncertainty of comparison between Gershun tube radiometer and spectral irradiation source standard is 2.83%, and the consistency of experimental result and theoretical result is 0.17%. The designed Gershun tube spectral radiometer can meet application requirements..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 612002 (2017)
Damage Inspection of Optical Surface Based on Galvanometer Scanning
Guo Yajing, Tang Shunxing, Jiang Xiuqing, Zhu Baoqiang, and Lin Zunqi
As a two-dimensional scanning device, galvanometer can be used to image surface damage status of different regions into CCD. The galvanometer scanning method can accomplish surface damage inspection of large-aperture optical elements without moving optical elements or imaging devices. A damage inspection method for larAs a two-dimensional scanning device, galvanometer can be used to image surface damage status of different regions into CCD. The galvanometer scanning method can accomplish surface damage inspection of large-aperture optical elements without moving optical elements or imaging devices. A damage inspection method for large-aperture optical elements based on galvanometer scanning is presented. The experiment is conducted based on the galvanometer scanning method. By setting reference points on the optical element surface, the damage size and location are obtained after scanning steps and image processing. Then, the results are compared with those from microscope. The resolution of the inspection system is (2.08±0.015) μm/pixel, and the inspection range is larger than 2.5 cm. The inspection accuracies in the horizontal and vertical directions are 3.76% and 1.37%, respectively. The inspection accuracy of damage size is 6.19%. It demonstrates that the galvanometer scanning damage inspection method can detect the damage status on the large-aperture optical element surface with high accuracy..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 612003 (2017)
Lasers and Laser Optics
Temperature Stability of Nd∶YAG/Nd∶YVO4 Combination Crystals Laser
Qu Pengfei, Wang Shiyu, Shao Xinzheng, Guo Zhen, Cai Defang, and Li Bingbin
In high power end-pumped solid state laser, the conventional Nd∶YAG crystal can be influenced by LD wavelength shift induced by temperature shift due to its narrow absorption bandwidth, which will lead to fluctuating of output power. In order to reduce the sensitivity of laser which is influenced by LD temperature, a cIn high power end-pumped solid state laser, the conventional Nd∶YAG crystal can be influenced by LD wavelength shift induced by temperature shift due to its narrow absorption bandwidth, which will lead to fluctuating of output power. In order to reduce the sensitivity of laser which is influenced by LD temperature, a combination crystals scheme between Nd∶YAG and Nd∶YVO4 is proposed. The Nd∶YAG with good thermophysical parameters is placed at the front end of LD to absorb most pumped energy, and Nd∶YVO4 with broad absorption spectrum at the rear of Nd∶YAG to absorb the rest pumped energy. The absorption efficiency and output power of the laser can be kept stable through the above complementary absorption during LD wavelength shift, and more tolerant to LD temperature variations. Experimental results show that the absorption efficiency of pumped energy can be improved to 90% by using the combination crystals at LD power 97.5 W in the range of LD work temperature 22-32 ℃. And the output power fluctuation is less than 8%, which reduces the sensibility to the LD temperature..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 614001 (2017)
Diagnostic Equipment Calibration Platform Based on Sub-Picosecond Ultraviolet Laser
Yuan Zheng, Deng Keli, Li Jin, Yang Zhiwen, Wu Bingjing, Chen Tao, Deng Bo, Qi Wenbo, Wang Qiangqiang, Cao Zhurong, and Liu Shenye
In order to make full use of output characteristics of high energy, ultrashort pulse width of sub-picosecond ultraviolet lasers, a calibration platform of laser inertial confinement fusion(ICF) diagnostic equipment is established. The calibration platform has such functions as laser energy measurement, optical transmisIn order to make full use of output characteristics of high energy, ultrashort pulse width of sub-picosecond ultraviolet lasers, a calibration platform of laser inertial confinement fusion(ICF) diagnostic equipment is established. The calibration platform has such functions as laser energy measurement, optical transmission delay, beam splitting and geometric decline, and sequential optical pulse generator, which can provide the structural support and high vacuum operating environment for the relevant diagnostic equipment. The mechanical and optical design is developed in all parts of the platform, and the platform is used to calibrate the X-ray diode response time, X-ray streak camera sweep speed, X-ray framing camera dynamic range and so on. The results show that the calibration platform matches the sub-picosecond ultraviolet calibration source well, and can achieve precise calibration of various diagnostic equipments..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 614002 (2017)
Thermal Stress Damage of Thin-Film Components Induced by Surface Impurities
Xu Jiao, Chen Lixia, You Xinghai, and Zhang Bin
Based on the thermodynamic theory of thin-film components, the thermal analysis model of thin-film components continuously radiated by high-power lasers is built up. On this basis, the heat transferring process of the thin-film components from impurities to their surrounding thin-film after the surface impurities absorBased on the thermodynamic theory of thin-film components, the thermal analysis model of thin-film components continuously radiated by high-power lasers is built up. On this basis, the heat transferring process of the thin-film components from impurities to their surrounding thin-film after the surface impurities absorbing heat is simulated, and the influences of surface cleanliness level and the impurity size on the thermal stress damage of the thin-film components are discussed. The results show that, under the continuous radiation of high-power lasers, the laser-energy-absorption of surface impurities gives rise to the relatively high increase of temperature. And the longer the laser irradiation time and the bigger the power density, the more the temperature of the impurities increases. After absorbing heat, the impurities with and without the reaching of melting points transfer heat to their surrounding thin film by the thermal-conduction and thermal-radiation ways, respectively. The temperature rise of the surface of thin-film components caused by thermal-conduction is obviously higher than that by thermal-radiation. Furthermore, the heat-transfer from impurities to surrounding thin-film results in a non-uniform temperature gradient, which further causes the thermal stress. The thermal stress increases with the increase of the temperature gradient, and the thermal stress damage is more likely to happen if the surface impurities localize within a certain range. In addition, the higher the surface cleanliness level of thin-film components and the more the number of impurities, the more easily the thin-film components are damaged..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 614003 (2017)
Analysis of Three-Dimensional Deposition Characteristics of Chromium atoms in the Straight Edge Diffraction Standing Wave Field
Yi Lufu, Xiong Xianming, Zhang Wentao, and Zhan Pingping
Nanostructures stripe deposition technique is a new method to develop nanostructures length standard transmission with the near resonance laser standing wave field manipulation in neutral atoms. In the process of focusing atoms, due to the presence of deposition substrate, a straight edge diffraction phenomenon occurs Nanostructures stripe deposition technique is a new method to develop nanostructures length standard transmission with the near resonance laser standing wave field manipulation in neutral atoms. In the process of focusing atoms, due to the presence of deposition substrate, a straight edge diffraction phenomenon occurs in the laser standing wave field, which affects the atomic trajectory and deposition grating. The model of laser standing wave field is established under the straight edge diffraction disturbance, and the three-dimensional trajectory and deposition characteristics of chromium atoms are simulated using the Runge-Kutta method. Considering the influence of laser power and detuning amount, we analyze the trajectory and deposition characteristics of chromium atoms from the full width at half maximum (FWHM) and the contrast. The results show that when the laser power and the detuning amount are 3.93 mW and 200 MHz, the FWHM and contrast of atomic deposition grating are 6.043 nm and 0.863, respectively. Under this condition, the best quality of atomic sedimentary grating can be acquired. Compared with the classical model, this model has considered the influence of standing wave field of straight edge diffraction disturbance, the simulation results are closer to the actual situation and can be theoretical guidance to the experiment..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 614004 (2017)
Hot-Corrosion-Resistance Property and Mechanism of Inconel X-750 Nickel-Based Alloy Processed by Laser Peening
Yang Yingqiu, Zhou Jianzhong, Sheng Jie, Chen Songling, Huang Shu, Meng Xiankai, and Yang Xiangwei
The strengthen treatment of Inconel X-50 nickel-based alloys are performed by laser peening (LP) with different pulse energies. The hot-corrosion behavior of specimens under different conditions is studied, and the mechanism of enhancement of hot-corrosion-resistance property by LP is discussed. The results show that tThe strengthen treatment of Inconel X-50 nickel-based alloys are performed by laser peening (LP) with different pulse energies. The hot-corrosion behavior of specimens under different conditions is studied, and the mechanism of enhancement of hot-corrosion-resistance property by LP is discussed. The results show that the corrosion rate of specimens after LP processing is obviously lower than that of the untreated specimens, and the higher the pulse energy is, the lower the corrosion rate of specimens after LP processing is. The untreated specimens exhibit two corrosion layers after hot-corrosion for 60 h where the outer corrosion layer is seriously corroded and thus the phenomenon of breaking and stripping off arises. The specimens after LP processing only appear an internal oxide layer after hot-corrosion for 60 h. The LP-induced residual stress layer effectively avoids the rupture of oxide films..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 614005 (2017)
Materials
Measurement of Effective Negative Refractive Index of Two-Dimensional Photonic Crystal Slabs
Jiang Qiang, Chen Jiabi, Liang Binming, Wang Yan, and Zhuang Songlin
Photonic crystals have a special dispersion characteristic, which can lead to negative refraction. The negative refraction of a two-dimensional photonic crystal slab is calculated theoretically and measured experimentally with the beam-displacement method. The two-dimensional field distribution for an incident light rePhotonic crystals have a special dispersion characteristic, which can lead to negative refraction. The negative refraction of a two-dimensional photonic crystal slab is calculated theoretically and measured experimentally with the beam-displacement method. The two-dimensional field distribution for an incident light refracted by this photonic crystal slab is obtained. The measured result shows that, as for the transverse electric (TE) light, the negative refraction in photonic crystals and the horizontal displacement in the opposite direction for the light exiting along the exit surface occur, and thus the effective refractive index is calculated as -0.44. In contrast, as for a transverse magnetic (TM) light, the negative refraction does not happen at all. The experimental result is well consistent with the simulated one..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 616001 (2017)
Effect of Li+ Doping on Upconversion Luminescence Property of SrLu2O4∶Ho3+/Yb3+ Phosphors
Liu Songbin, Chen Mengyao, Liu Shuifu, Niu Hu, Ye Xinyu, Hou Dejian, and You Weixiong
A series of Li+ doped SrLu2O4∶Ho3+/Yb3+ phosphors are prepared with high-temperature solid-state reaction method. The Li+ doped samples maintain the primary orthorhombic structure. The Li+ ions can be introduced into the host lattice through the approach of substitutional doping and interstitial doping. By adding approA series of Li+ doped SrLu2O4∶Ho3+/Yb3+ phosphors are prepared with high-temperature solid-state reaction method. The Li+ doped samples maintain the primary orthorhombic structure. The Li+ ions can be introduced into the host lattice through the approach of substitutional doping and interstitial doping. By adding appropriate Li+ ions to the samples, the agglomeration of samples can be minimized and the average diameter of particles is about 3 μm. The impurities (OH- and CO32-) with high phonon energy can be reduced, which reduces the quenching centers and increases upconversion emission intensity. The intense green emission and weak red emission are observed under the excitation of the 980 nm laser, which are attributed to the 5F4, 5S2→5I8 and 5F5→5I8 transitions, respectively. With the introduction of Li+ ions to the SrLu2O4∶Ho3+/Yb3+ sample, the upconversion emission is found to be significantly enhanced, which is attributed to the modification of local crystal field symmetry around Ho3+ ions by Li+ doping. Compared with other alkali-metal-ion dopings, the Li+ doped sample has the strongest luminescence intensity due to the smallest ionic radius and the strongest electronegativity of Li+ ions. The analysis result of pump-power dependence show that the green and red emissions are both involved in a two-phonon process..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 616002 (2017)
Medical Optics and Biotechnology
Nonconvex L1-2 Regularization for Fast Cone-Beam X-Ray Luminescence Computed Tomography
Zhang Haibo, Geng Guohua, Zhao Yingcheng, Sun Yi, Yi Huangjian, Hou Yuqing, and He Xiaowei
Cone-beam X-ray luminescence computed tomography (CB-XLCT) is an attractive hybrid imaging modality, and it is important for early detection of diseases, targeted therapy and drug development. However, the columns of system matrix used for CB-XLCT imaging tend to be highly coherent, which means L1 minimization may not Cone-beam X-ray luminescence computed tomography (CB-XLCT) is an attractive hybrid imaging modality, and it is important for early detection of diseases, targeted therapy and drug development. However, the columns of system matrix used for CB-XLCT imaging tend to be highly coherent, which means L1 minimization may not produce the sparsest solution. A novel reconstruction method by minimizing the difference between L1 and L2 norms is proposed. To solve the non-convex L1-2 minimization problem, an iterative method based on the difference of convex algorithm (DCA) is presented. In each DCA iteration, the update of solution involves an L1 minimization subproblem, which is solved by the alternating direction method of multipliers with an adaptive penalty. The performance of the proposed method is investigated with simulated data and in vivo experimental data. The results demonstrate that the DCA for L1-2 minimization outperforms the representative algorithms for L1, L2, L1/2, TV and L0 when the system matrix is highly coherent. The proposed method can solve the rapid imaging problem of CB-XLCT effectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 617001 (2017)
Nonlinear Optics
Periodically Lumped Amplification and Recovery of Soliton in Dispersion-Decreasing Optic Fiber Link
Wang li, Yang Rongcao, Jia Heping, Tian Jinping, and Xue Wenrui
The exact soliton solution is analyzed based on the variable coefficient nonlinear Schrdinger equation including the decreasing dispersion and periodically lumped-amplification by a simple transformation. Meanwhile, the transmission, amplification and recovery of soliton is achieved in dispersion-decreasing and periodThe exact soliton solution is analyzed based on the variable coefficient nonlinear Schrdinger equation including the decreasing dispersion and periodically lumped-amplification by a simple transformation. Meanwhile, the transmission, amplification and recovery of soliton is achieved in dispersion-decreasing and periodically lumped-amplification (DDPLA) optic fiber link. The results show that periodic amplification and recovery of the soliton could be realized through the balance among the dispersion, loss and amplifier gain. Moreover, regulating the gain of the amplifier according to the fiber loss and the amplification period, or adjusting the amplification period on the basis of the fiber loss and the amplifier gain, the periodic amplification or recovery of soliton obtained in the DDPLA could be realized. In addition, the stability of soliton and interaction between adjacent solitons are discussed numerically. The obtained results are theoretical significance to soliton transmission and the exact configuration of periodic amplifier in real dispersion-decreasing and periodic amplification link..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 619001 (2017)
Optical Design and Fabrication
Optical System Design of Electronic Endoscope Objective with Q-type Aspheres
Li Chuang, Xue Changxi, Yang Hongfang, and Zhang Ran
By using the retrofocus structure with a “negative-positive” form as the initial structure, we design an electronic endoscope objective (EEO) optical system with Q-type aspheres working in the visible light band, whose total field of view is 110°, focal length is 1 mm, F number is 3.3, maximum clear aperture is 3 By using the retrofocus structure with a “negative-positive” form as the initial structure, we design an electronic endoscope objective (EEO) optical system with Q-type aspheres working in the visible light band, whose total field of view is 110°, focal length is 1 mm, F number is 3.3, maximum clear aperture is 3 mm, and total length is 7.89 mm. The optical system is composed of six pieces of lenses, including two cemented doublet and one lens with Q-type aspheres of both sides. The design results show that the modulation transfer function (MTF) values are higher than 0.4 at Nyquist spatial frequency of 143 lp/mm, which is approaching the diffraction limit. For validating superiority of Q-type aspheres in EEO system design, an EEO system is designed with power series (PS) aspheres in the same computing platform and with the same structure parameters. The comparison results show that Q-type aspheres have stronger ability to correct the aberration of the system, and they are helpful to improve the efficiency of system optimization. The aspheric departure between the designed Q-type aspheres and their closest spheres is very little, which is beneficial to enhance the detection precision and working efficiency of aspheric optical components, and the cost can be reduced. The designed EEO system with Q-type aspheres has lower assembly sensitivity, which helps to improve the system assembly efficiency..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 622001 (2017)
Surface Shape Model Research for Compound Parabolic Concentrators with Circular Absorber and Its Simulation Verification
Duan Pengfei, Gui Tete, Chen Fei, Yang Chunxi, and Bie Yu
The fixed solar concentrating system exhibits such advantages as wide heat-collecting temperature band, no tracking device, no mechanical movement, easy integration, and stable operation. Therefore, we study the critical component surface shape structure of the solar compound parabolic concentrators (CPC) with circularThe fixed solar concentrating system exhibits such advantages as wide heat-collecting temperature band, no tracking device, no mechanical movement, easy integration, and stable operation. Therefore, we study the critical component surface shape structure of the solar compound parabolic concentrators (CPC) with circular absorber. A theoretical model of surface shape structure of CPC with circular absorber is established and the analytic solution of the model is obtained. The optical characteristics of the theoretical model is validated by the optical design software TracePro. Meanwhile, a novel solar collector system with CPC is designed, and the calculation method for optical characteristics is established by the optical characteristics of surface shape of CPC with circular absorber. The numerical calculation is conducted by the optical characteristics of the designed system. The results show that the solar radiation collected by the solar collector with CPC is higher than that of the solar collector with evacuated tubes, and the average ratio is 34.57%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 622002 (2017)
Optical Devices
Design and Experimental Investigation of Triple-Band Metamaterial Broadband Bandpass Filter
Wang Haoshen, Han Kui, Sun Wei, Li Haipeng, Wang Weihua, Fu Wenyue, and Shen Xiaopeng
A triple-band metamaterial broadband bandpass filter (BPF) which is independent to polarization and stable at wide-angle incidence is designed, fabricated and tested. Simulation results show that the designed BPF has three broadband passbands. The center frequencies are 7.22, 10.10 ,14.46 GHz. 3 dB relative bandwidths A triple-band metamaterial broadband bandpass filter (BPF) which is independent to polarization and stable at wide-angle incidence is designed, fabricated and tested. Simulation results show that the designed BPF has three broadband passbands. The center frequencies are 7.22, 10.10 ,14.46 GHz. 3 dB relative bandwidths are 17.5%, 20.2% and 17.4%. The transmission efficiencies at center frequency are -0.85 dB, -0.69 dB and -1.73 dB, respectively. This BPF is insensitive to the electromagnetic wave polarization, because the structure is rotational symmetry. Additionally, three bands of the designed BPF can still keep stable performance, when incident angle reaches 40°. By monitoring the surface current distributions at resonant frequencies, the physical mechanism of the triple-band filtering is analyzed. The proposed triple-band metamaterial broadband BPF is hopeful to take part in multi-frequency imaging technology, information communications and other fields owing to its multi-band filtering, independent to polarization and stable at wide-angle incidence..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 623001 (2017)
Multi-Band Frequency Conversion Scheme Based on Single Optical Frequency Comb for Satellite Communication
Lin Tao, Zhao Shanghong, Zhu Zihang, Li Xuan, Zheng Qiurong, Qu Kun, and Hu Dapeng
A simple, flexible and stable frequency conversion approach based on a single optical frequency comb (OFC) is proposed. In this method, a dual-polarization quadrature phase shift keying modulator (DP-QPSK) is employed. The DP-QPSK is an integrate modulator which integrates two dual-parallel Mach-Zehnder modulators (DPMA simple, flexible and stable frequency conversion approach based on a single optical frequency comb (OFC) is proposed. In this method, a dual-polarization quadrature phase shift keying modulator (DP-QPSK) is employed. The DP-QPSK is an integrate modulator which integrates two dual-parallel Mach-Zehnder modulators (DPMZM). One DPMZM is working as an OFC generator. Another is working as carrier suppressive single sideband modulator to generate single sideband signal. An orthogonal and coupled signal is output from this modulator. This signal is converted to a signal with fixed polarization angle under the control of polarization controller and the polarizer. After the signal is put into the photoelectric detector, the microwave signal is generated. The simulation results show that multi-band frequency conversion can be realized by properly adjusting six direct current (DC) bias points of the proposed integrate modulator and disjunctive phase shifter. For example, the signal at C band 3.8 GHz can be converted to X, Ku, K and Ka bands. The signal at X band 9.6 GHz can be down-converted to C band or up-converted to Ku, K, Ka bands. In addition, the system emerges a good adaption to the DC bias points drafting and has a good operability..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 623002 (2017)
Optical Design of Large-Area Projection Solar Simulator
Du Zhiqiang, Zhang Liming, Si Xiaolong, Chen Hongyao, Xu Weiwei, Wang Shaolin, Ma Wenjia, and Yang Chunyan
In order to simulate the large-area solar irradiation in the space environment, a systematic design procedure for a new projection solar simulator is presented. Based on etendue theory, the energy transfer process of the system is analyzed. An array of four xenon lamps is used as light source. An object-space telecentrIn order to simulate the large-area solar irradiation in the space environment, a systematic design procedure for a new projection solar simulator is presented. Based on etendue theory, the energy transfer process of the system is analyzed. An array of four xenon lamps is used as light source. An object-space telecentric projection system is designed to realize a large area and uniform illumination. The simulation of Zemax software and the actual measurement for the system are carried out to verify the rationality. The results show that the effective irradiance surface of the solar simulator is 1000 mm×1000 mm, the irradiance can get 1263 W/m2, and the irradiance non-uniformity is less than ±4.82%. The solar simulator can provide a reliable solar radiation for the space environment test of satellites, which conquers the limitations of large size and high cost of the traditional large solar simulators..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 623003 (2017)
Characteristics of Light Extraction for Surface-Microcavity Photonic Crystal LED
Hu Yonglu, Liu Daoliu, Wang Bo, Wu Junfang, and Li Chao
In this paper, we propose and study a light-emitting diode (LED) based on the surface-microcavity photonic crystal (PC). The beaming-collimation effect is generated by the coherent-coupling interaction of the emergent light from the multiple resonant cavities. As a result, the light extraction efficiency of LED is imprIn this paper, we propose and study a light-emitting diode (LED) based on the surface-microcavity photonic crystal (PC). The beaming-collimation effect is generated by the coherent-coupling interaction of the emergent light from the multiple resonant cavities. As a result, the light extraction efficiency of LED is improved, as well as the spatial directivity of emergent light. By optimizing the structure of the surface PC LED, the light extraction efficiency of the surface-microcavity PC LED is 77.3% higher than that of the prefect PC LED, and 1.8 times higher than that of the normal slab LED. Simultaneously, the proposed surface-microcavity PC LED has more obvious far-field energy converging effect than prefect PC LED and normal slab LED. This feature ensures the emergent light with better spatial directivity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 623004 (2017)
Physical Optics
Light Intensity Scintillation of Airy Beam
Wang Jiaan, Wang Xinlan, Guo Linyang, Che Ying, and Yin Peng
The light intensity scintillation of Airy beam is analyzed based on von-Karman model and Rytov method. According to the uneven distribution of light intensity on the receiving plane of receiver, a surface light intensity scintillation model of Airy beam is proposed, and surface light intensity scintillation expressionsThe light intensity scintillation of Airy beam is analyzed based on von-Karman model and Rytov method. According to the uneven distribution of light intensity on the receiving plane of receiver, a surface light intensity scintillation model of Airy beam is proposed, and surface light intensity scintillation expressions of Airy beam are derived. The simulation results show that, when the beam width is fixed and the propagation distances are equal, the smaller the exponential truncation factor is, the smaller the light intensity scintillation is. The smallest light intensity scintillation of Airy beam is achieved with propagation distance of 3 km, exponential truncation factor of 0.2 and beam width around 1.6 cm. Furthermore, the light intensity scintillation of Airy beam is smaller than that of Gaussian beam with the same light source intensity and receiving light intensity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 626001 (2017)
Spatial Mode Distributions of Ince-Gaussian Beams Modulated by Phase Difference Factor
Ma Haixiang, Li Xinzhong, Li Hehe, Tang Miaomiao, Wang Jingge, Tang Jie, Wang Yishan, and Nie Zhaogang
A novel type of Ince-Gaussian (IG) beam, named as PIG (Ince-Gaussian beam with phase difference) beam, based on the initial phase difference factor modulation between even mode and odd mode of IG beam is proposed. The PIG beam is generated by the linear superposition of the even mode and the odd mode of traditional IG A novel type of Ince-Gaussian (IG) beam, named as PIG (Ince-Gaussian beam with phase difference) beam, based on the initial phase difference factor modulation between even mode and odd mode of IG beam is proposed. The PIG beam is generated by the linear superposition of the even mode and the odd mode of traditional IG beam after the even mode being multiplied an exponential phase factor with an initial phase difference of φ. The modulation properties of the initial phase difference factor on spatial mode of the PIG beam are mainly studied when other parameters are the same. Numerical simulations and experimental results show that the PIG beam changes from positive vortex state to negative vortex state when φ continuously increases from 0 to π. The vortex state is vanished when φ=π/2. As φ is equal to integer multiple of π, the switch from the positive vortex state to the negative vortex state is realized. As φ is equal to half-integer multiple of π, light traps of the PIG beams can be accurately controlled to move on the oval orbit. The PIG beam will provides an additional degree of freedom for micro-particle operation and beam micro-machining..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 626002 (2017)
Diversity Research on Exceptional Points in High Dimensional Non-Hermitian System
Cheng Shihang, Zhu Kejia, and Ding Yaqiong
Unlike the traditional Hermitian system, a non-Hermitian system has exceptional points. When one parameter evolves to an exceptional point, a phase transition occurs in the non-Hermitian system, i.e., two eigenstates collapse and their corresponding eigenvalues merge into one. The two-state and four-state non-HermitianUnlike the traditional Hermitian system, a non-Hermitian system has exceptional points. When one parameter evolves to an exceptional point, a phase transition occurs in the non-Hermitian system, i.e., two eigenstates collapse and their corresponding eigenvalues merge into one. The two-state and four-state non-Hermitian systems are studied by using the coupled metamaterial artificial atoms. Various evolution traces of the eigenvalues of non-Hermitian systems are studied by recording the variation of peak frequency of coherent absorption with the loss parameter in an open system for electromagnetic waves. Theoretical and electromagnetic-field simulated results show that, five kinds of exceptional points can form by different combination ways of eigenstates in the four-state non-Hermitian system. Among them, the exceptional points at which more than two eigenstates merge is called as high-order exceptional points..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 626003 (2017)
Refraction Characteristics of Spatial Bending Beams
Xu Yongzheng, Li Hui, Wang Li, and Zhang Zhongyue
Spatial bending beams have important applications in optical trapping, fiber sensing, and so on. In these applications, spatial media environment plays an important role. A theoretical method is proposed based on the principle of spatial bending beam excitation. Snell′s law is introduced to invert every geometrical raySpatial bending beams have important applications in optical trapping, fiber sensing, and so on. In these applications, spatial media environment plays an important role. A theoretical method is proposed based on the principle of spatial bending beam excitation. Snell′s law is introduced to invert every geometrical ray of spatial bending beam and describe the refraction of spatial bending beam at air-dielectric interface. Besides, the spatial bending beam is as an example for carrying out simulation based on the finite element method. The refraction mechanism of spatial bending beam at air-dielectric interface may serve as a reference for elucidating the refraction mechanism of arbitrary spatial bending beam motivated by phase inversion..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 626004 (2017)
Focusing of Scattering Light by Improved Feedback Wavefront Shaping Technique Based on Golden Section Method
Hu Xiansheng, Pu Jixiong, Ji Xuanxuan, and Chen Ziyang
Speckles of laser scattered by scattering media can be modulated into focused spots when the phase of incident beam is modulated. A method to improve feedback wavefront shaping technique based on golden section method is introduced, and the focusing of beam scattered by scattering media is realized. Compared with the sSpeckles of laser scattered by scattering media can be modulated into focused spots when the phase of incident beam is modulated. A method to improve feedback wavefront shaping technique based on golden section method is introduced, and the focusing of beam scattered by scattering media is realized. Compared with the sequential algorithm, the superiority of the golden section algorithm in searching maximum value of the unimodal function is theoretically analyzed, and the scattering focusing process is numerically simulated. The results show that golden section algorithm performs better than sequential algorithm in modulation rate when the total number of modulation segments and the phase modulation precision of a single segment are changed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 626005 (2017)
Quantum Optics
Quantum Key Distribution Protocols Based on Asymmetric Channels of Odd Coherent Sources
Kang Danna, and He Yefeng
In order to solve the problem that the key generation rate is too low when the non-ideal single photon source is used in the traditional quantum key distribution protocol, the light source is optimized, an odd coherent light source is used to replace the traditional weak coherent light source, and a measurement-device-In order to solve the problem that the key generation rate is too low when the non-ideal single photon source is used in the traditional quantum key distribution protocol, the light source is optimized, an odd coherent light source is used to replace the traditional weak coherent light source, and a measurement-device-independent quantum key distribution protocol based on the asymmetric channels of odd coherent sources is proposed. The performances of measurement-device-independent quantum key distribution protocols for symmetric and asymmetric channels with the odd coherent light source are compared. The relationship between the channel loss and the key generation rate and single-side efficiency in the proposed protocol is analyzed. The simulation results show that the introduction of the odd coherent light source makes up the deficiency of the traditional light source and also reduces the number of photons greatly. With the increase of the channel loss, the key generation rate decreases, but the performance of the asymmetric channel is still higher than that of the symmetric channel..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 627001 (2017)
Remote Sensing and Sensors
Fusion and Classification of SAR and Optical Image with Consideration of Polarization Characteristics
Wan Jianhua, Zang Jinxia, and Liu Shanwei
Full polarimetric synthetic aperture radar (SAR) possessed rich polarization information, it has a significant advantage for coverings recognition. A fusion method which took into account polarization characteristics of full polarimetric SAR is proposed based on SAR and medium resolution optical image. Full polarimetriFull polarimetric synthetic aperture radar (SAR) possessed rich polarization information, it has a significant advantage for coverings recognition. A fusion method which took into account polarization characteristics of full polarimetric SAR is proposed based on SAR and medium resolution optical image. Full polarimetric SAR is carried out polarimetric target decomposition, polarization characteristics and optical image is fused with the improved hue, saturation, value (HSV) transform method. The fusion image is classified based on the object-oriented method. The results show that the proposed fusion method is superior to the traditional HSV fusion method for effectively using the polarimetric information and texture information of full polarimetric SAR. Object-oriented classification method can reduce the speckle noise of fusion image from SAR. The overall classification accuracy is better than that of high resolution optical image, and the classification accuracy of coverings which is sensitive to the polarization information is obviously better than that of high resolution optical image..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 628001 (2017)
Scattering
Simultaneous Inversion Method of Radiative Characteristic Parameters of Internal Medium and Surface for One-Dimensional Slab
Zhou Yifan, and Cheng Qiang
The effect of the physical object BRDF surface is considered, and the radiative characteristic parameters of the internal medium and surface for a one-dimensional slab are inversed simultaneously by utilizing the spectral data such as directional hemisphere reflectivity, directional hemisphere transmissivity, normal reThe effect of the physical object BRDF surface is considered, and the radiative characteristic parameters of the internal medium and surface for a one-dimensional slab are inversed simultaneously by utilizing the spectral data such as directional hemisphere reflectivity, directional hemisphere transmissivity, normal reflectivity and normal transmissivity. The method can be applied to the inversion of radiative characteristic parameters of these three kinds of medium, such as the absorbing and scattering medium, the highly absorbing medium and the highly scattering medium, and the inversion result coincides well with its given initial value..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 629001 (2017)
Spectroscopy
Denoising of Polycyclic Aromatic Hydrocarbons Spectra Based on EMD and Mathematical Morphology
Yuan Yuanyuan, Wang Shutao, Wang Yutian, Wang Zhifang, and Yang Zhe
Based on the strong fluorescence property of polycyclic aromatic hydrocarbons benzo［k］ fluoranthene (BkF), a fluorescence detection system is constructed and ten BkF methanol solution samples with different concentrations are prepared to analyze their fluorescence characteristics. In order to proceed qualitative and quBased on the strong fluorescence property of polycyclic aromatic hydrocarbons benzo［k］ fluoranthene (BkF), a fluorescence detection system is constructed and ten BkF methanol solution samples with different concentrations are prepared to analyze their fluorescence characteristics. In order to proceed qualitative and quantitative analyses well, the improved empirical mode decomposition (EMD) threshold method combined with mathematical morphology is applied to denoising the fluorescence spectrum, which is compared with the EMD threshold denoising method. The results show that the proposed method can smooth the denoised fluorescence spectra preferably, make the linear correlation coefficient between the fluorescence intensity and the sample concentration high and reach 0.99746, make the signal-to-noise ratio increase, and make the mean square error between the original signal and the denoised signal decrease from 0.0053 to 0.0012. The proposed method possesses a remarkable denoising effect, which effectively improves the analytical precision of spectra and provides a new method for preprocessing fluorescence spectra..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 630001 (2017)
Nonlinear Interference Spectrum Data Reconstruction Algorithm for Image Plane Interference
Zhang Zhinan, Li Libo, Hu Bingliang, Chen Jiejing, Gao Xiaohui, and Yang Fanchao
The static Michelson interferometer is an entity type image plane interferometer, which can solve the technical difficulty of large field of view of interferometer. In the sampling process, nonlinear interference error is introduced by the interferometer, which leads to a consequence that the spectrum cannot be recoverThe static Michelson interferometer is an entity type image plane interferometer, which can solve the technical difficulty of large field of view of interferometer. In the sampling process, nonlinear interference error is introduced by the interferometer, which leads to a consequence that the spectrum cannot be recovered accurately, so the nonlinear interference error needs to be corrected. A theoretical model of nonlinear interference error is analyzed, a nonlinear interference spectrum data reconstruction algorithm is presented, and a simulation is carried out. The simulation results indicate that the target spectrum can be recovered successfully by the reconstruction algorithm with numerical fitting, and the nonlinear interference error is eliminated. The reconstruction algorithm using Cauchy dispersion formula fitting is more precise than the reconstruction algorithm using linear fitting, and the relative error between the recovery spectrum and the input spectrum is less than 0.7% at the absorption peak..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 630002 (2017)
Denoising Method for Plant Hyperspectral Data Based on Grouped 3D Discrete Cosine Transform Dictionary
Xu Ping, Xiao Chong, Zhang Jingcheng, and Xue Lingyun
In order to solve the problems that noise intensity of each band for plant hyperspectral image is different and noise exists in both spatial and spectral domains, a sparse representation denoising method is proposed based on the grouped three-dimensional (3D) discrete cosine transform (DCT) dictionary. Firstly, the speIn order to solve the problems that noise intensity of each band for plant hyperspectral image is different and noise exists in both spatial and spectral domains, a sparse representation denoising method is proposed based on the grouped three-dimensional (3D) discrete cosine transform (DCT) dictionary. Firstly, the spectral characteristics of the plants are analyzed and the bands are grouped according to the spectral correlation. Secondly, local mean standard deviation of eliminating edges is used to estimate the noise standard deviation of hyperspectral images, which provides the reference threshold for denoising algorithm. Finally, a sparse representation denoising method based on 3D DCT dictionary is constructed for denoising plant hyperspectral images. Experimental results show that, comparing with the original data and the denoising method of two-dimensional (2D) DCT dictionary, the average signal-to-noise ratios of the noise evaluation by the proposed method are improved by 18.2 dB and 9.2 dB in the spectral domain. Therefore, the proposed method can denoise not only in the spatial domain but also in the spectral domain..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 630003 (2017)
Simultaneously Measuring Method for Zn(II)、Co(II) Based on Feature Interval Association-Partial Least Squares
Zhu Hongqiu, Zou Shengnan, Yang Chunhua, Li Yonggang, and Chen Junming
A simultaneously measuring method for Zn(II)、Co(II) based on feature interval association-partial least squares is proposed to solve the problem that the ultraviolet visible (UV-Vis) absorption spectrum of mixed solution with Zn(II), Co(II) is seriously overlapped and difficult to separate. For the absorption spectrum A simultaneously measuring method for Zn(II)、Co(II) based on feature interval association-partial least squares is proposed to solve the problem that the ultraviolet visible (UV-Vis) absorption spectrum of mixed solution with Zn(II), Co(II) is seriously overlapped and difficult to separate. For the absorption spectrum in the range of 400~800 nm of mixed solution, the method of feature interval association is used to select the characteristic interval of Zn(II) and Co(II) in the way of partition, and the optimal feature interval of Zn(II) and Co(II) is selected by the minimum root mean square error of cross validation VRMSECV and the maximum determination coefficient R2. Finally, these optimal intervals are associated to establish partial least squares (PLS) model, and ion concentrations of Zn(II) and Co(II) are obtained. The result indicates that the proposed method can not only reduce the complexity of the wavelength selection, but also ensure the stability of the wavelength selection process. Thus, the VRMSECV and the predicted average relative error of Zn(II) model are reduced to 0.0483 and 3.48%. The VRMSECV and the predicted average relative error of Co(II) model are reduced to 0.0501 and 4.25%. And the R2 of Zn(II) and Co(II) are increased to 99.41% and 99.22%. In addition, the application of the method can fix the scanning spectrum of Zn(II) and Co(II) in the selected feature intervals, which greatly improves the efficiency of spectrum detection..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 630004 (2017)
Thin Films
Design of Broad-Angle Extreme Ultraviolet Multilayer Coatings Based on Quantum Evolutionary Algorithm
Zhang Chao, Zhang Jierui, Wang Yiming, Kuang Shangqi, and Xie Yao
A design approach of the theoretical film system with broad-angle extreme ultraviolet (EUV) multilayers coatings based on the real-coded quantum evolutionary algorithm (RQEA) is proposed. Based on the RQEA and the real-coded genetic algorithm (RGA), the theoretical design and analysis for Mo/Si multilayers coatings witA design approach of the theoretical film system with broad-angle extreme ultraviolet (EUV) multilayers coatings based on the real-coded quantum evolutionary algorithm (RQEA) is proposed. Based on the RQEA and the real-coded genetic algorithm (RGA), the theoretical design and analysis for Mo/Si multilayers coatings with broad angles is performed. It is found that the RQEA has obvious advantages of small population, high efficiency, and high accuracy, which makes the RQEA possess potential application value in the field of optical film design. In addition, the broadband Mo/Si multilayer coatings with reflectivity of up to 50% at incidence angle of 0°-18° and at incident wavelength of 13.5 nm are designed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 631001 (2017)
X-Ray Optics
Flash X-ray Diffraction Measurement of LiF Crystal Deformation Under Shock Loading
Tang Bo, Hei Dongwei, Ma Ge, Sheng Liang, Ouyang Xiaoping, Zhou Haisheng, Wei Fuli, Xia Jingtao, Luo Jianhui, and Liu Xu
A pulse X-ray diffraction measurement system is established by using a miniaturized flash X-ray source on gas gun loading experimental platform. The system is used to study the microstructure change of LiF crystal lattice under plate shock loading experiments. Single pulse X-ray diffraction images from LiF crystals areA pulse X-ray diffraction measurement system is established by using a miniaturized flash X-ray source on gas gun loading experimental platform. The system is used to study the microstructure change of LiF crystal lattice under plate shock loading experiments. Single pulse X-ray diffraction images from LiF crystals are obtained under different shock loading pressures. Experimental results show that crystal lattice of LiF is compressed when LiF crystal is loaded along ［100］ orientation, and the amount of compression is related to the shift of diffraction peak position. Quantitative measurement of material microstructure change under shock compression can be achieved by pulse X-ray diffraction measurement system using miniaturized flash X-ray source. The system described here has advantages such as small size and easy to use, and it provides effective method to study the microscopic mechanism of elastic-plastic deformation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 37, Issue 6, 634001 (2017)
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