Contents
2013
Volume: 33 Issue 12
56 Article(s)
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Atmospheric Optics and Oceanic Optics
Dual Field of View Lidar for Observing Atmospheric Aerosols over Wuhan
Li Jun, Gong Wei, Mao Feiyue, and Zhang Jinye
A dual field of view lidar for observing atmospheric aerosols is described. The lidar has two independent receiving fields. One observes higher atmosphere by noncoaxial system, and the other observes lower atmosphere (especially planetary boundary layer) by coaxial system. The higher atmospheric data are obtained by coA dual field of view lidar for observing atmospheric aerosols is described. The lidar has two independent receiving fields. One observes higher atmosphere by noncoaxial system, and the other observes lower atmosphere (especially planetary boundary layer) by coaxial system. The higher atmospheric data are obtained by combining analog and photon counting. It effectively improves observing ability limited by large dynamic range of the receiving signals. The observing data are shown and analyzed. The results show that this lidar is an effective tool for observing atmospheric aerosols. The reliability has been validated by comparing with another lidar system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1201001 (2013)
Applicable Probability Distribution Model of Refracted Star Number in Field of View of Indirectly Sensing Horizon Star Sensor
Wang Haiyong, Jin Guangrui, and Zhao Yanwu
Aiming at the engineering problem that the refracted star number in the field of view (FOV) of a star sensor is not enough to carry out indirectly sensing horizon, it is necessary to study the probability distribution function (PDF) of refracted star number in the FOV. A brief introduction of the principle of stellar rAiming at the engineering problem that the refracted star number in the field of view (FOV) of a star sensor is not enough to carry out indirectly sensing horizon, it is necessary to study the probability distribution function (PDF) of refracted star number in the FOV. A brief introduction of the principle of stellar refraction is given. The proportion coefficient of the stratosphere strip area fallen in the FOV to the whole FOV area is deduced, and combined with the validated PDF of the total star number in FOV, the PDF of the refracted star number is obtained at last. The feasibility analysis on the analytic positioning method based on stellar refraction is finished by using the PDF model, presenting the quantification relationship between the FOV, apparent magnitude (Mv), apogee distance and probability distribution. The plotted refracted star number PDF curve is similar to that by Monte Carlo simulation results, with Poisson parameter bias of 1.48, an equivalent of relative error of 12.8%. The simulation results show the correctness of the PDF model, which will be helpful to the parameter design of the star sensor used for indirectly sensing horizon through starlight refraction..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1201002 (2013)
Analysis of Aerosol Optical Properties and Sources at Shenzhen
Yang Honglong, Lu Chao, Liu Aiming, and Yang Su
Atmospheric aerosols are not only a major component of urban air pollution, but also one of the largest sources of uncertainty in the assessment of the climate evaluation. Aerosol optical properties are investigated at Shenzhen in Pearl River Delta of China according to the observation data of aerosol from 2011 to 2012Atmospheric aerosols are not only a major component of urban air pollution, but also one of the largest sources of uncertainty in the assessment of the climate evaluation. Aerosol optical properties are investigated at Shenzhen in Pearl River Delta of China according to the observation data of aerosol from 2011 to 2012. The aerosol at Shenzhen is characterized by strongly light-absorbing characteristics. Mean values (standard deviation, SD) of scattering and absorption coefficients for the entire period are (175.4±127.8)×10-6 m-1 and (30.5±24.5)×10-6 m-1, respectively. The mean single scattering albedo (SSA) for the entire period is estimated as 0.83, which is higher than the values reported for the domestic cities, such as Beijing and Guangzhou, but lower than that in foreign cities. The absorption, scattering coefficients and SSA values show a seasonal cycle with the lowest values in summer, while the highest values in winter. Their diurnal variations cannot be solely explained with the change of atmospheric boundary layer, and the influence of local wind patterns, variation of pollution, photochemial reaction and the complex chemical reaction at night should also be considered. A trajectory cluster analysis is applied to discern the source characteristics of aerosol optical properties for different air masses. The results show that the values of optical properties are all high when the air masses come from the dense population centers in industrial areas and contaminated regions, especially in winter. The cluster-mean SSA for aerosol coming from the polluted areas is not only higher than those from the “clean” directions, but also higher than the reported values for the regions with high pollution emissions..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1201003 (2013)
Study on the Measurement of Coherence Length by Differential Image Motion Monitor
Yu Longkun, Wu Yi, Hou Zaihong, and Jing Xu
In order to have a thorough knowledge of characteristics of atmospheric coherence length measured by using differential image motion method, differential image motion monitor (DIMM) is studied deeply. Based on theoretical analyses and numerical simulation, several important problems existing in DIMM are discussed, and In order to have a thorough knowledge of characteristics of atmospheric coherence length measured by using differential image motion method, differential image motion monitor (DIMM) is studied deeply. Based on theoretical analyses and numerical simulation, several important problems existing in DIMM are discussed, and their solutions are elucidated. Problems include formulas, sub-pupil diameter and displacement of sub-pupils. Accuracy of DIMM is improved, requirements of instrument structure condition are reduced, and suitable scope of DIMM is expanded..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1201004 (2013)
Diffraction and Gratings
Optimization of Wide Spectrum Anti-Reflective Grating for Solar Cell
Kong Weijin, Cao Kaihua, You Chenglong, Yun Maojin, Wang Xingyao, Qin Xiaoqi, Li Kai, and Wu Shigang
An anti-reflective grating used for solar cell is proposed based on SiO2/TiO2 film to reduce its surface loss. It consists of substrate, relief structure and surface thin film. Rigorous coupled wave theory and genetic algorithm are employed to optimize the parameters such as groove depth, duty cycle, incident angle andAn anti-reflective grating used for solar cell is proposed based on SiO2/TiO2 film to reduce its surface loss. It consists of substrate, relief structure and surface thin film. Rigorous coupled wave theory and genetic algorithm are employed to optimize the parameters such as groove depth, duty cycle, incident angle and thickness of surface thin film according to the merit function of the weighted average reflectivity. The optimized grating has the lower weighted average reflectivity than 2.16% with the incident wavelength from 300 nm to 1100 nm and the incident angle around ±40°. The lowest weighted average reflectivity is only 1.04%. Simulation results show sufficient manufacture tolerance of the designed grating..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1205001 (2013)
Technique Based on Image Superposition for Optical Image Storage and Reconstruction
Yin Shen, and Tao Shaohua
A technique for image storage and reconstruction based on the superposition of multiple grating-modulated images is experimentally introduced. Blazed gratings with different groove orientations and groove angles are used to superpose many gray-scale images into a single phase element. In the experiment, the phase distrA technique for image storage and reconstruction based on the superposition of multiple grating-modulated images is experimentally introduced. Blazed gratings with different groove orientations and groove angles are used to superpose many gray-scale images into a single phase element. In the experiment, the phase distribution of the superposed images is loaded onto a spatial light modulator (SLM) with a computer to modulate the incident beam. The laser beam is then Fourier transformed by a convex lens. A pinhole is used to filter the desired diffraction spot of an image in the frequency domain. Another convex lens is used for image reconstruction, and a CCD camera is used to record the reconstructed images. The experimental results demonstrate that 22 gray-scale images can be stored in a phase element and reconstructed with high fidelity. The method has advantages such as high-volume data storage, easy implementation, high security, and so on..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1205002 (2013)
Generation of Femtoscond Double Pulses by Two-Layer Volume Holographic Grating
Yan Xiaoyuan, Yan Xiaona, Dai Ye, Yang Xihua, and Ma Guohong
Based on Kogelnik′s coupled-wave theory and matrix optics, generation of femtosecond double pulses by modulating the thickness of buffer layer of two-layer volume holographic grating is discussed. The diffraction field expressions with a femtosecond pulse reading out the two-layer volume holographic grating are deducedBased on Kogelnik′s coupled-wave theory and matrix optics, generation of femtosecond double pulses by modulating the thickness of buffer layer of two-layer volume holographic grating is discussed. The diffraction field expressions with a femtosecond pulse reading out the two-layer volume holographic grating are deduced. The relation curve of instantaneous diffraction intensity distribution varying with thickness of buffer layer numerically simulated. Simulation results show that when the buffer layer thickness changes from 4 mm to 11 mm, the diffraction pulse turns into double pulses and the interval between double pulses is linearly proportional to the thickness of the buffer layer. We use the diffraction theory and diffraction field expressions to give an explanation. At last, we discuss time delay of diffraction double pulses with respect to the thickness of the buffer layer by group time delay of periodic media, and it is shown that the slope of the pulse interval with respect to the thickness of the buffer layer is 2 times of that of pulse time delay..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1205003 (2013)
Fiber Optics and Optical Communications
Fiber Optic Magnetic Field Sensor Based on Femtosecond Laser Micromachining
Dai Yutang, Zhou Guangfu, Li Tao, Yang Minghong, and Hu Wenbin
A kind of magnetic field sensing solution is proposed based on 3-D microstructure machining of fiber. The femtosecond laser with wavelength of 780 nm is employed to ablate a spiral microstructure into cladding of fiber Bragg grating (FBG), and the magnetostrictive film (TbDyFe) is deposited in the microstructure by magA kind of magnetic field sensing solution is proposed based on 3-D microstructure machining of fiber. The femtosecond laser with wavelength of 780 nm is employed to ablate a spiral microstructure into cladding of fiber Bragg grating (FBG), and the magnetostrictive film (TbDyFe) is deposited in the microstructure by magnetron sputtering process to form a new fiber optic magnetic field sensor. The microstructure can improve the axial retractility of fiber and enhance the surface area of the thin film deposition in order to enhance the sensitivity of probe. The theory of enhancing sensitivity from spiral microstructure is established and the preporation methods and techniques of the fiber optic magnetic field sensor probe are described. The magnetic response results of several probes with different parameters are demonstrated. It is shown that from the experimental results, the sensing probe with pitch of 50 μm is most sensitive to magnetic field. In ideal case, the sensitivity of the probe with microstructure can be enhanced nearly five times as high as that with non-microstructured standard FBG..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1206001 (2013)
Beat-Length Measurement of Polarization Maintaining Fibers Based on Broadband Fiber Circular Polarizers
Xiao Yueyu, Wang Zhaozhao, Shi Zhidong, Peng Lei, and Yan Jinkui
A new method to measure the beat-length of polarization maintaining fibers is presented. The key components of the all-fiber measuring system are a broadband light source and two broadband fiber circular polarizers. Theoretical analysis shows that, compared with the polarization interference system made up by fiber linA new method to measure the beat-length of polarization maintaining fibers is presented. The key components of the all-fiber measuring system are a broadband light source and two broadband fiber circular polarizers. Theoretical analysis shows that, compared with the polarization interference system made up by fiber linear polarizers, circular polarizers can eliminate the influence of the angles between the axis of polarization maintaining fibers on the visibility of the interference fringe. The beat-length of a panda polarization maintaining fiber is investigated for verification. Experimental results are in good agreement with the theoretical analysis. The accuracy and repetition of beat-length measurement are 0.1 mm, and the visibility of the interference fringe is better than 0.9. Since there is no need for accurate angle adjustment between polarization maintaining fiber devices, the measurement system has the advantages of simple structure and low operation requirement..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1206002 (2013)
Investigation on the Cladding Etched Single-Mode Fiber Acousto-Optic Tunable Filter and Its Axial Strain Characteristics
Kang Zexin, Liu Chao, Sun Jiang, Ma Lin, You Haidong, and Jian Shuisheng
The filtering properties of all-fiber acousto-optic tunable filter (AOTF) based on cladding etched sing-mode fiber (SMF) are investigated experimentally. Influenced by the acousto-optic effcect, the acousto-optic coupling efficiency from LP01 core mode to LP11 cladding mode is enhanced by reducing the cladding diameterThe filtering properties of all-fiber acousto-optic tunable filter (AOTF) based on cladding etched sing-mode fiber (SMF) are investigated experimentally. Influenced by the acousto-optic effcect, the acousto-optic coupling efficiency from LP01 core mode to LP11 cladding mode is enhanced by reducing the cladding diameter. At a fixed cladding diameter, the resonant wavelength of the AOTF shifts to the shorter wavelength side as the acoustic frequency increases. Moreover, the change of resonant wavelength with the acoustic frequency is numerically calculated and the simulation curves are in good agreement with the experimental results. The axial strain characteristics of all-fiber AOTF based on cladding etched SMF are analyzed experimentally. The results show that the resonant wavelength appears red shift as the increasing of axial strain, so it′s easy to achieve the tunable filter using the axial strain dependence. The tuning bandwidth is inverse to the acousto frequency and the cladding diameter. When the cladding diameter is kept at 35 μm and the acousto frequency is fixed at 1 MHz, an AOTF with tuning bandwidth greater than 150 nm is demonstrated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1206003 (2013)
Chromatic Dispersion Monitoring Based on Auto-Correlation Function of Signal Power Waveform
Zhao Donghe, Xi Lixia, Yang Song, Weng Xuan, Zhang Xiaoguang, and Zhang Wenbo
It is confirmed through theoretical derivation that auto-correlation function of signal power waveform contains a pulse, whose location can be used to estimate chromatic dispersion. On this basis, the algorithm of chromatic dispersion monitoring is given. This method is verified in 112 Gb/s (28 GBaud) polarization diviIt is confirmed through theoretical derivation that auto-correlation function of signal power waveform contains a pulse, whose location can be used to estimate chromatic dispersion. On this basis, the algorithm of chromatic dispersion monitoring is given. This method is verified in 112 Gb/s (28 GBaud) polarization division multiplexing non return to zero quadrature phase shift keying (PDM-NRZ-QPSK) experimental system. Using OptiSystem and Matlab, 56 Gb/s single polarization QPSK and 112 Gb/s PDM-QPSK simulation systems are setup and the applicability of this method to code pattern of NRZ, RZ67, RZ50 and RZ33 is analyzed. The experiment and simulation results are consistent with the analytical derivation, which confirms the feasibility of the method. The experimental monitoring error is less than 275 ps/nm, and the monitoring error of simulation is less than 185 ps/nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1206004 (2013)
Geometric Optics
Adjustment of Three-Mirror Off-Axis Freeform System
Wang Chao, Zhang Xin, Wang Lingjie, Zhang Jianping, and Zhang Jizhen
In accordance with a three-mirror off-axis freeform system, the alignment method of combining benchmark transmission and computer-aided alignment is put forward. Based on computer-generated hologram (CGH), an entire and precise space benchmark is founded to ensure the quality of prime alignment in the process of benchmIn accordance with a three-mirror off-axis freeform system, the alignment method of combining benchmark transmission and computer-aided alignment is put forward. Based on computer-generated hologram (CGH), an entire and precise space benchmark is founded to ensure the quality of prime alignment in the process of benchmark transmission. During computer-aided alignment, by collecting interferograms of several fields of optical system by means of autocollimating interferometry, aberrations could be obtained from parameters of modified orthogonal Zernike polynomials in square area. Furthermore, the sensitivity matrices related to the incorrect parameters derived from Zemax software and those of modified orthogonal Zernike polynomials in square area are used to determine the incorrect parameters. The results show that the average root-mean-square (RMS) value of the system is 0.1641λ (λ=632.8 nm) and the average modulation transfer function (MTF) value of the system is 0.4534 after iterations..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1208001 (2013)
Holography
A Computing-Free Wavefront Sensing Method Based on Holography
Yao Kainan, Wang Jianli, Wu Yuanhao, Wang Bin, Cao Jingtai, Wang Zongyang, and Liu Wei
To increase wavefront detecting speed of the wavefront sensor, a new computing-free method based on holography is researched. With thin hologram approximation, we get the numerical model based on the fast Fourier transform (FFT) algorithm and the first 8 order Zernike aberrations are detected by holographic wavefront sTo increase wavefront detecting speed of the wavefront sensor, a new computing-free method based on holography is researched. With thin hologram approximation, we get the numerical model based on the fast Fourier transform (FFT) algorithm and the first 8 order Zernike aberrations are detected by holographic wavefront sensor under this numerical model. The root-mean-square (RMS) value of detection error is 0.24 rad. An experimental device is set up to validate the numerical simulation in our laboratory and the RMS value of detection error is 0.29 rad. The experimental results indicate that the computing-free wavefront sensing method based on holography can detect the low order Zernike aberrations with high efficiency..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1209001 (2013)
Imaging Systems
Freeform Optical System Alignment Based on Artificial Neural Networks
Wang Yu, Zhang Xin, Wang Lingjie, and Wang Chao
Freeform surfaces freeform optical surfaces are widely utilized in optical engineering domain, while the traditional computer-aided alignment methods fail to guide the alignment of the optical system containing. A novel method using artificial neural networks is proposed to assist the alignment of optical system. The lFreeform surfaces freeform optical surfaces are widely utilized in optical engineering domain, while the traditional computer-aided alignment methods fail to guide the alignment of the optical system containing. A novel method using artificial neural networks is proposed to assist the alignment of optical system. The logical model of alignment with neural networks is introduced, and two alignment simulation examples are taken to verify the practicability of this method. The alignment results show that when the optical path difference distribution or the simulated Zernike polynomial coefficients of the system exit pupil wavefront are used as imaging quality parameters，the root-mean-square errors of misalignment parameters computed by the neural network method are less than 7.04%. The neural network method provides a certain reference to alignment of freeform surface systems..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1211001 (2013)
Non-Uniformity Correction Method Based on Standard Deviation Value Compensation after Moment Matching
Zhu Shanyou, Zhang Guixin, Gong Cailan, Zhu Lingya, He Huaying, and Hu Yong
Non-uniformity of infrared focal plane arrays is one of the key problems that must be solved before its quantitative applications. The moment matching method is adopted in correction of infrared non-uniformity. Due to the disadvantages of the method, such as changing of the image spectral variance and possibly producinNon-uniformity of infrared focal plane arrays is one of the key problems that must be solved before its quantitative applications. The moment matching method is adopted in correction of infrared non-uniformity. Due to the disadvantages of the method, such as changing of the image spectral variance and possibly producing new stripe noise, by comparing the output and the mean value difference for each detector between before and after the standard moment matching correction, an improved moment matching method based on the standard deviation value compensation is proposed. The quantitative and the qualitative analysis results show that the proposed method improves the non-uniformity correction precision, while the spectral variance of different objects in original image is better retained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1211002 (2013)
Mutual Information of Ghost Imaging Systems
Li Enrong, Chen Mingliang, Gong Wenlin, Yu Hong, and Han Shensheng
The mutual information between the detected signals and the targets of ghost imaging systems is calculated, and its relation to the reconstructions is studied by numerical simulations. Results show that for given type of targets, there is a certain set of speckle patterns maximizing the mutual information under which cThe mutual information between the detected signals and the targets of ghost imaging systems is calculated, and its relation to the reconstructions is studied by numerical simulations. Results show that for given type of targets, there is a certain set of speckle patterns maximizing the mutual information under which condition the best reconstruction can be achieved using the same number of sampling data points. Based on these results, it is proposed to design and optimize the ghost imaging system by maximizing the mutual information..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1211003 (2013)
Research on Spatial Resolution of Integral Imaging
Wu Chunhong, Wang Qianqian, Wang Hongxia, and Lan Jinhui
Through analyzing the reconstructed optical distribution in the displaying stage, the relationship among micro-lens parameters, planar recording resolution and spatial resolution of the integral imaging system is obtained. The results show that the spatial resolution is relevant to the pitch size and focal length of thThrough analyzing the reconstructed optical distribution in the displaying stage, the relationship among micro-lens parameters, planar recording resolution and spatial resolution of the integral imaging system is obtained. The results show that the spatial resolution is relevant to the pitch size and focal length of the micro-lens. Small sized micro-lens is preferred to improve spatial resolution. However, the requirement for planar recording resolution increases with the decrease of the micro-lens size. The requirement for recording resolution also increases with the increase of the object depth. The results can be used in the optimal design of integral imaging..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1211004 (2013)
Hyperspectral Microscopic Imaging Based on Image Plane Interferometry
Li Jianxin, Zhou Wei, Meng Xin, and Zhu Rihong
In order to obtain the spectral images of objects with small scale, a method of hyperspectral microscopic imaging based on the image plane interferometry is proposed. The interferometric imaging system with microscope objective, collimating lens, lateral shearing beam splitter, imaging lens and detector is researched. In order to obtain the spectral images of objects with small scale, a method of hyperspectral microscopic imaging based on the image plane interferometry is proposed. The interferometric imaging system with microscope objective, collimating lens, lateral shearing beam splitter, imaging lens and detector is researched. An adjustable solid structure of the lateral shearing beam splitter is adopted and rotated to achieve the interferogram of the object. The microscopic imaging principle, magnification, spatial resolution, spectral resolution and depth of field are analyzed. An experimental prototype is constructed to carry out experiments on the epidermis of broad bean leaves specimen, and the spectral images in visible band are recovered. Experimental results validate the good performance of the system with high throughput and high spectral resolution, and show that a new method for the microscopic spectral imaging is provided..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1211005 (2013)
Passive THz Imaging System Based on the Crank-Rocker Mechanism
Zhang Jingshui, Zhu Weiwen, Zhao Yuejin, Zhao Ruizhong, and Dong Liquan
In order to solve the problem of low efficiency and high complexity in traditional single channel passive THz imaging system, a novel passive terahentz (THz) imaging system with single channel and optical-mechanical scanning is designed. A crank-rocker mechanism is employed to realize the fact movement of the line scanIn order to solve the problem of low efficiency and high complexity in traditional single channel passive THz imaging system, a novel passive terahentz (THz) imaging system with single channel and optical-mechanical scanning is designed. A crank-rocker mechanism is employed to realize the fact movement of the line scanning mirror, and the two-dimensional imaging is achieved through the cooperation of the line scanning mirror and the frame scanning mirror. A Cassegrain antenna of 390 mm in diameter and 94 GHz Schottky diodes are used in this system to help to accomplish the fast scanning imaging of the objects. The single frame imaging time of the system is only 20 s, the field of view (FOV) is 30°×36°, and the angular resolution is up to 0.6°. The experimental results show that the system can image the human body, and effectively detect dangerous items concealed under the clothes. The system of fast scanning has many advantages such as low cost, high efficiency and simple structure, and provides a useful reference for the development of passive THz imager in miniaturization and high-speed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1211006 (2013)
Study of Single-Pixel Detection Computational Imaging Technology Based on Compressive Sensing
Ma Yanpeng, Wang Yanan, Wang Yikun, Ge Mingfeng, Wang Yuxi, Qi Hongxing, and Shu Rong
Based on the theory of compressive sensing, the overall structure system of the single-pixel detection computational imaging, the design of the observation matrix and image reconstruction algorithm are analysed, and correlation algorithm is simulated by Matlab. Simulation results show that compressive sensing used to sBased on the theory of compressive sensing, the overall structure system of the single-pixel detection computational imaging, the design of the observation matrix and image reconstruction algorithm are analysed, and correlation algorithm is simulated by Matlab. Simulation results show that compressive sensing used to single-pixel detection computational imaging can reduce the sampling and can clearly reconstruct image. In addition, a long-range external imaging system prototype is built in the laboratory, and the imaging experiment is conducted in the indoors using parallel light source. The experimental results show that the imaging system has better spatial resolution. The single-pixel detection computational imaging is extended further by building dispersion optical path in the imaging system, the system structure of computational imaging spectrometer is established, the feasibility of which compressive sensing is used to the computational imaging spectrometer is analyzed, and the computational imaging spectrometer is analyzed in theory..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1211007 (2013)
Instrumentation, Measurement and Metrology
Wavelength Difference Studies of Wavelength Calibration Based on Diffuse Reflector
Zhang Zihui, Wang Shurong, Huang Yu, and Lin Guanyu
In the experiment of high-precision spectral calibration, the results of spectral calibration, when using the tilt diffuse reflector as dodging device, are different from vertical exposure. Through analysing the process of energy transfer, we find that the radiant flux on the entrance slit is uneven when using the tiltIn the experiment of high-precision spectral calibration, the results of spectral calibration, when using the tilt diffuse reflector as dodging device, are different from vertical exposure. Through analysing the process of energy transfer, we find that the radiant flux on the entrance slit is uneven when using the tilt diffuse reflector, which causes the wavelength difference. We use the double grating monochromator as the instance, and put all of the radiant flux of different wavelengths on the entrance slit. And then we can know that wavelength difference is -0.0283 nm, when using the 45°tilt diffuse reflector to wavelength calibration. Finally, making the mercury as light source, by scanning the 296.7283 nm and 365.0157 nm wavelengths with two methods of using the diffuse transmittance plate to vertical irradiation and using the 45° tilt diffuse reflector plate irradiation, the wavelength difference are -0.029 nm and -0.0286 nm. The results of the experiment can certify that the tilt reflect diffuser is the main factor to cause the wavelength difference in the spectral calibration experiment..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1212001 (2013)
Real-Time Laser Facula Detection Based on Top-Three-Neighborhood-Region Continuous-Pixels Numbering
Xu Wenyu, Bai Tingzhu, Liu Yang, and Liang Zhen
The real-time and high precision detection algorithm of the laser facula is proposed. This work has digitized 14 bit laser facula video with the high frequency and high sensitive CCD; analyzed the feature of the laser facula is analyzed, the laser facula region by top-three-neighborhood-region continuous-pixels numberiThe real-time and high precision detection algorithm of the laser facula is proposed. This work has digitized 14 bit laser facula video with the high frequency and high sensitive CCD; analyzed the feature of the laser facula is analyzed, the laser facula region by top-three-neighborhood-region continuous-pixels numbering algorithm is detected after segmenting the facula region by the threshold; the reason of surplus facula in the whole laser facula region is analyzed. The surplus facula region with the average threshold algorithm is subtracted, the more accurate facula centroid (including the center of mass and the center of figure) is gotten, and made the flow of the facula detection from the video frame, named operation-serial algorithm, which solve the problem of that tranditional neighbored-frame-subtraction algorithm can not dectect the inverse facula frame and the continous facula frame when the centroids of the facula are different. The experimental result shows that the proposed algorithm can be used to the online and offline detection of real-time and high precision laser facula practically..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1212002 (2013)
Inverse Fringe Generation Method Based on Pruning Optimization Algorithm
Li Xue, and Zhang Qican
Inverse projected fringe technique is a fast and robust optical three-dimensional (3D) shape inspection technique, which is applied to online or batch inspection. In recent years, people pay more attention to the technique and apply it in many fields. A new method for generating inverse fringe is proposed. This method Inverse projected fringe technique is a fast and robust optical three-dimensional (3D) shape inspection technique, which is applied to online or batch inspection. In recent years, people pay more attention to the technique and apply it in many fields. A new method for generating inverse fringe is proposed. This method adopts normal mapping transform relationship to transfer coordinate. Then, it adopts the horizontal and vertical equal phase lines to obtain crosspoint which is the homologous pixel of the pixel on projector plane, so we can get the inverse fringe finally. The pruning optimization algorithm for getting the crosspoint is proposed, based on equal phase lines′ characteristic. The algorithm gradually decreases the unnecessary pixels of two equal phase lines. Finally, it can find four nearest pixels of the crosspoint, then the crosspoint can be calculated by solving two linear equations. The algorithm comes to sub-pixel level. The pruning optimization algorithm and the method proposed in Ref.[10] are used in contrast experiments. Standard phase differences in the computer simulation experiment are 0.000798 rad and 0.0046 rad respectively. Standard phase differences in the real experiment are 0.0431 rad and 0.0292 rad, respectively. The conclusion indicates that the optimization algorithm can improve precision of inverse fringe projection effectively, and reduce time consumption by exactly searching four nearest pixels with fast speed..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1212003 (2013)
Lasers and Laser Optics
Dual-Wavelength Orthogonally Polarized Yb3+-Doped Double Clad Fiber Laser
Feng Dejun, Huang Wenyu, Liu Guanxiu, and Zhang Maosen
A stable continuous-wave dual-wavelength Yb3+-doped fiber laser is demonstrated, in which the resonance cavity is composed of a fiber Bragg grating fabricated in a polarization maintaining fiber (PM-FBG) and a high reflectivity dichromatic mirror. The laser achieves output power of 1.0 W, signal to noise radio (SNR) ofA stable continuous-wave dual-wavelength Yb3+-doped fiber laser is demonstrated, in which the resonance cavity is composed of a fiber Bragg grating fabricated in a polarization maintaining fiber (PM-FBG) and a high reflectivity dichromatic mirror. The laser achieves output power of 1.0 W, signal to noise radio (SNR) of 48 dB, slope efficiency of 34%, as well as a very narrow linewidth of 0.2 nm. The dual-wavelength laser′s tuning range is 8 nm by stretching and compressing the PM-FBG which is glued on an arch elastic beam. The polarization characteristics of the laser are then verified by measuring the laser power transmitted through a Glan-Thomson polarizer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1214001 (2013)
Analysis of Depolarizing Characteristics on Focal Spot Using a Polarization Control Plate
Zhong Zheqiang, Li Zelong, Zhou Bingjie, and Zhang Bin
A polarization control plate (PCP) is applied to achieve incoherent superposition of beamlets on target for further improving illumination uniformity in inertial confinement fusion (ICF) driver. By analyzing the effect of PCP on the modification of the polarization of beamlets, the model for the transmittance function A polarization control plate (PCP) is applied to achieve incoherent superposition of beamlets on target for further improving illumination uniformity in inertial confinement fusion (ICF) driver. By analyzing the effect of PCP on the modification of the polarization of beamlets, the model for the transmittance function of PCP is built up. The effects of PCP on the characteristics on focal spot are simulated numerically and analyzed theoretically. The expectation and variance of degree of polarization (DOP) are used to describe depolarization characteristics on focal spot, and the contrast is employed to evaluate illumination uniformity. The effects of number of PCP elements, bandwidth and integral time on the characteristics on focal spot are discussed in detail. The results show that polarization control plate can well obtain depolarized laser beam and improve uniformity on target..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1214002 (2013)
Machine Vision
Point Pattern Matching Based on Multiple Spectral Representations
Tang Jun, Liu Zhizhong, Liang Dong, and Wang Nian
Addressing the weakness of the single spectral representation, an algorithm is proposed for point pattern matching on the basis of multiple spectral representations. The eigenvalue series obtained by various matrix representations of graphs are used as the descriptor of feature point. The similarities between the givenAddressing the weakness of the single spectral representation, an algorithm is proposed for point pattern matching on the basis of multiple spectral representations. The eigenvalue series obtained by various matrix representations of graphs are used as the descriptor of feature point. The similarities between the given local structural descriptors are evaluated via the technique of multiview spectral embedding. Combined with the geometric consistency, point pattern matching problem is solved by using the method of probabilistic relaxation. Comparative experiments conducted on both synthetic data and real images verify the effectiveness and robustness of the proposed method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1215001 (2013)
Calibration of 3D Structured Light Measurement System Based on the Properties of Lens Distortion
Chen Hui, Mi Baoxiu, and Gao Zhiqiang
Calibration is an important process in 3D vision measurement for the structured light system. The calibration results influence measurement accuracy. After studying the properties of lens distortion, a new calibration method is proposed in which the target region is divided into many sub-regions of concentric rings forCalibration is an important process in 3D vision measurement for the structured light system. The calibration results influence measurement accuracy. After studying the properties of lens distortion, a new calibration method is proposed in which the target region is divided into many sub-regions of concentric rings formed by treating the optical axis as a center point along with a given radius. Then, according to the reprojection method, calibrations are done one by one. Since this method takes the impact of large filed of view as well as lens distortion into account, calibration accuracies of both local and global regions are improved dramatically. The experimental results show that to the field of about 1050 mm×750 mm divided into two regions, the accuracy for projector calibration increases by 72.8% and the system precision reaches 28.9 μm, which indicate the advantage of this method on distortion processing. The method does not rely on any special calibration equipment, and operates easily and conveniently with good accuracy. It is proved that the proposed method can meet measurement requirements of large field, high precision, and be more compatible to real-time system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1215002 (2013)
Materials
Improvement of Dye-Sensitized Solar Cells with TiO2 Nanoarray-TiO2/Graphene Nanocrystal Composite Film as Photoanode
Wang Rong, Zhang Haiyan, Wang Wenguang, and Liu Hui
TiO2/graphene nanocrystals are synthesized at 200 ℃ with graphene and Ti(OC4H9)4 as precursors by hydrothermal synthesis method, which is fabricated on fluorine-doped tin oxide (FTO) and TiO2 nanoarray films by screen-printing.The composite films are evaluated with scanning electron microscopy (SEM) and photovoltaic teTiO2/graphene nanocrystals are synthesized at 200 ℃ with graphene and Ti(OC4H9)4 as precursors by hydrothermal synthesis method, which is fabricated on fluorine-doped tin oxide (FTO) and TiO2 nanoarray films by screen-printing.The composite films are evaluated with scanning electron microscopy (SEM) and photovoltaic tests. The result shows that we print TiO2/graphene nanocrystals on the TiO2 nanoarrays to prepare the photoanode of dye-sensitized solar cells by the double-layer structure of “nanocrystal+nanoarray”, which increases the absorbability for dye and absorption of ultraviolet-visible. The efficiency of the cell which uses TiO2 nanoarray coated by TiO2/graphene nanocrystals film as photoanode increases by 35% comparing with the TiO2/graphene nanocrystals film, and the highest efficiency is 3.53%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1216001 (2013)
Analytic Model of Optical Constants for Infrared Absorption Material with Nanostructure
Li Yongqian, Wang Binbin, Su Lei, Zhu Zhenyu, and Zhou Zili
The estimation of equivalent optical parameters of the nanostructure absorber materials will help to understand its absorption, reflection and radiation characteristics. The effective optical parameters of the metamaterials are estimated by the S-parameters proposed by Smith in 2002, which assumes the nanostructure metThe estimation of equivalent optical parameters of the nanostructure absorber materials will help to understand its absorption, reflection and radiation characteristics. The effective optical parameters of the metamaterials are estimated by the S-parameters proposed by Smith in 2002, which assumes the nanostructure metamaterials to be homogeneous bulk material, without reflecting the relationship between the equivalent optical parament, the geometrical structure and material characteristics. Here an analytical theory in which the Drude-Lorentz model is adopted to describe the dispersion relations of metamaterials′ absorptive characteristics in infrared (IR) is presented. Based on the effective electron density and the equivalent circuit analysis, a functional description between the geometrical parameters and its Drude-Lorentz model parameters has been built. This analysis on periodic arrangements of rectangular structures array is performed. The model establishes the quantitative relationship between structure parameters, material parameters and its optical constants. It offers an accurate prediction for their dispersive behavior at near-IR wavelengths..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1216002 (2013)
Hydrothermal Synthesis of Mercaptoethylamine Stabilized CdTe Quantum Dots and Its Use for Detection of Cu2+
Gan Tingting, Zhang Yujun, Zhao Nanjing, Xiao Xue, Yin Gaofang, and Shi Chaoyi
Water-soluble mercaptoethylamine (CA) stabilized CdTe (CA-CdTe) quantum dots (QDs) are synthetized by hydrothermal synthesis method, and the fluorescent responses of as-prepared CA-CdTe QDs to different metal ions are studied. Based on the selective fluorescence quenching of Cu2+ to CA-CdTe QDs, the fluorescent responsWater-soluble mercaptoethylamine (CA) stabilized CdTe (CA-CdTe) quantum dots (QDs) are synthetized by hydrothermal synthesis method, and the fluorescent responses of as-prepared CA-CdTe QDs to different metal ions are studied. Based on the selective fluorescence quenching of Cu2+ to CA-CdTe QDs, the fluorescent responses of CA-CdTe QDs with particle sizes of 3.27 nm and 3.60 nm to Cu2+ are studied. The study results show that the fluorescence quenching process of Cu2+ to CA-CdTe QDs can be described well by Stern-Volmer fluorescence quenching equation. There is a good linear relationship between the fluorescence intensity F0/F and the concentration of Cu2+ when the concentration of Cu2+ is in the ranges of 4×10-6～44×10-6 mol·L-1 and 1.6×10-6～40×10-6 mol·L-1. The linear correlation coefficients are 0.9876 and 0.9964 respectively, and the detection limits are 8.30×10-7 mol·L-1 and 5.08×10-7 mol·L-1 respectively. The study results also show that the difference of particle sizes of CA-CdTe QDs could not affect the detection and analysis of Cu2+. The fluorescence method of detecting Cu2+ based on CA-CdTe QDs is simple, rapid and sensitive, which can be used well for analysis and detection of Cu2+ in actual water samples..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1216003 (2013)
Optical Property of Three-Dimensional Photonic Crystal Simulated by Scalar Wave Approximation Method
Zhao Duobiao, Jiang Yuanyuan, Shan Jing, Wang Jiwei, and Tan Tianya
Mainly aiming at optimizing and improving the scalar wave approximation method, the scalar wave approximation method is used to simulate the transmission spectrum of the three-dimensional photonic crystal. The basic idea and calculation steps of the scalar wave approximation method are introduced. Then we optimize and Mainly aiming at optimizing and improving the scalar wave approximation method, the scalar wave approximation method is used to simulate the transmission spectrum of the three-dimensional photonic crystal. The basic idea and calculation steps of the scalar wave approximation method are introduced. Then we optimize and improve this method. The research on the photonic band gap is emphasized. The experimental data are compared with the simulation result in order to verify the accuracy of the method. The multi-layer three-dimensional photonic crystals are prepared by the fluid chemical vapor deposition method and their transmission spectra are measured. The experimental results show that the scalar wave approximation method can simulate the optical behavior of the three-dimensional photonic crystal..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1216004 (2013)
Medical Optics and Biotechnology
Determination of Optical Parameters of Turbid Media Based on Real Coded Genetic Algorithm
Li Fei, Zhang Yuanzhi, Wang Yikun, Zhu Ling, Liu Yong, and Wang An
Determination of optical parameters of turbid media is quite useful in the photodynamic therapy and optical noninvasive diagnostics. A kind of real coded genetic algorithm incorporated with inverse Monte Carlo method and graphics processing unit based acceleration technology is proposed, which can determine optical parDetermination of optical parameters of turbid media is quite useful in the photodynamic therapy and optical noninvasive diagnostics. A kind of real coded genetic algorithm incorporated with inverse Monte Carlo method and graphics processing unit based acceleration technology is proposed, which can determine optical parameters from the spatially resolved diffuse reflectance of turbid media by Monte Carlo simulation. Fitness function of accumulated square differences, random tournament selection operator, uniform random crossover operator with extended radius, uniform mutation operator, champion mutation operator are designed to guaranty the algorithm to converge with good population diversity. In the range 0≤μa≤100 cm-1 and 0≤μs≤1000 cm-1, the average relative errors are 0.25% and 0.58%, and the root mean-square errors (RMSEs) are 0.32 cm-1 and 1.68 cm-1 for the absorption coefficient and for the scattering coefficient, respectively, which means that this algorithm is feasible and accurate enough for determination of optical parameters of turbid media..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1217001 (2013)
Nonlinear Optics
Raman Effect on Gain Spectrum of Different Frequency Propagation Regimes in Photonic Crystal Fibers
Chai Hongyu, Jia Weiguo, Han Feng, Menkeneimule, Yang Jun, and Zhang Junping
The expression of gains is derived from the coherently coupled nonlinear Schrdinger (NLS) equation in consideration of Raman effect when two laser pulses with different wavelengths are emitted into birefringent photonic crystal fiber along two polarization axes. The result shows the symmetry of gain spectrum is damageThe expression of gains is derived from the coherently coupled nonlinear Schrdinger (NLS) equation in consideration of Raman effect when two laser pulses with different wavelengths are emitted into birefringent photonic crystal fiber along two polarization axes. The result shows the symmetry of gain spectrum is damaged compared with no consideration of Raman effect by numerical simulation. The gain spectrum is broaden and gain peak is reduced with higher-order dispersion increasing when two polarization modes are in the normal dispersion and anomalous dispersion regions. The gain spectrum is not obvious influenced by the higher-order dispersion when two polarization modes are in different dispersion regions. The result also shows that the two polarization mode dispersion coefficients majorly impact on Stokes and anti-Stokes of the gain spectrum, respectively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1219001 (2013)
Analysis of Influence of Beam Smoothing on Third Harmonic Generation in SGII Upgrade
Ji Lailin, Liu Chong, Zhu Baoqiang, Wu Rong, Zhou Shenlei, and Lin Zunqi
The influence of beam smoothing on third harmonic generation (THG) in SGII upgrade is analyzed with the nonlinear coupled wave equation. Simulation results show that the continuous phase plate (CPP) designed for 400 μm focus spot causes the conversion efficiency decreasing by 1.4% or so, and the contrast of near field The influence of beam smoothing on third harmonic generation (THG) in SGII upgrade is analyzed with the nonlinear coupled wave equation. Simulation results show that the continuous phase plate (CPP) designed for 400 μm focus spot causes the conversion efficiency decreasing by 1.4% or so, and the contrast of near field increasing by 0.02 or so in theory, which is within the acceptable tolerance. While the focus spot reaches 800 μm, the conversion efficiency decreases by about 6% and the contrast increases by 0.05 or so, which is out of the acceptable tolerance, and the scheme of the CPP should be improved. The 60 GHz bandwidth of smoothing by spectral dispersion (SSD) causes the conversion efficiency decreasing by about 5%, with obvious temporal intensity modulation, but influence of the divergence caused by SSD is very small. To maintain the stability of the THG, the bandwidth should be reduced reasonably at high fluence operation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1219002 (2013)
Optical Design and Fabrication
Prism Hyperspectral Imaging Optical System Design with Rectangular Aperture
Wu Congjun, Yan Changxiang, Liu Wei, and Zhang Junqiang
In order to meet the needs of space-borne hyper-spectral imaging, the parameters of optical system are determined based on analyzing application requirements. Rectangular aperture is used, instead of circle aperture, and doublet prism and single prism are used as dispersion elements to design visible near-infrared (VNIIn order to meet the needs of space-borne hyper-spectral imaging, the parameters of optical system are determined based on analyzing application requirements. Rectangular aperture is used, instead of circle aperture, and doublet prism and single prism are used as dispersion elements to design visible near-infrared (VNIR) and short-wave infrared (SWIR) spectrometer respectively. Telecentric three-mirror anastigmat (TMA) is adopted to design the telescope objective. Principle of cemented prisms used to compensate the nonlinear dispersion of single prism is discussed. TMA and spectrometers are designed with Zemax optical software, and the field splitter along the track direction is used to achieve imaging of VNIR and SWIR respectively. According to the overall analysis, the optical system meets the indicators of spectral resolution and ground resolution. Using the rectangular aperture not only can reduce the size in longitudinal dimension, but also is helpful to the aberration correction, which is conducive to the practical application of engineering. The VNIR band dispersion result shows that doublet prism is a useful method to correct the nonlinear dispersion of prism..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1222001 (2013)
Design of Three-Mirror Non-Coaxial Zoom Objective Based on Deformable Mirror
Cheng Hongtao
The optical zoom of three-mirror non-coaxial system is reached by introducing two deformable mirrors. The matrix optics is employed to analyze the first order characteristic of optical system and obtain system focusing formula. Combining the features of non-coaxial zoom system and aberration theories of plane-symmetricThe optical zoom of three-mirror non-coaxial system is reached by introducing two deformable mirrors. The matrix optics is employed to analyze the first order characteristic of optical system and obtain system focusing formula. Combining the features of non-coaxial zoom system and aberration theories of plane-symmetric optical system, the conditions of removing the spherical aberration, the constant astigmatism, the constant coma are deduced. Meanwhile, the arched distortion produced by tilt image is eliminated according the Scheimpflug condition. Finally, a new design of all-reflection non-coaxial zoom objective is presented. The results indicate that maximum root-mean-square radius is from 5.4791 μm to 11.117 μm, which satisfies the zoom objective lens specification. The design principles and methods provide a good quest for further making use of deformable mirror to design zoom system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1222002 (2013)
Design of Non-Null Interferometer Based on Point Source Array for Testing Freeform Surface
Shen Hua, Li Jia, Zhu Rihong, and Rong Sihai
Freeform optical surface is a new generation of ideal optical element because it can effectively correct image aberrations and greatly simplify optical system structures. Because of its high gradients and strong deviations from ideal sphere, it is extremely difficult to measure freeform optical surface with sufficient Freeform optical surface is a new generation of ideal optical element because it can effectively correct image aberrations and greatly simplify optical system structures. Because of its high gradients and strong deviations from ideal sphere, it is extremely difficult to measure freeform optical surface with sufficient accuracy, which is the key limitation on its fabrication and application. Therefore, a novel non-null interferential method based on the use of multiple test beams for illuminating freeform surface with different angels is presented, which can compensate local gradients of freeform optical surface. A reverse optical design method based on “black box” theory is proposed, which can resolve the problems caused by non-rotational asymmetry surface. A real non-null interferometer for testing freeform surface is designed, and an eyeglass with non-rotational asymmetry surface is measured successfully, which verifies the feasibility of the system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1222003 (2013)
Optical Devices
A Deformed Ellipsoid Condenser Beneficial to the Uniformity of the Solar Simulator
Lü Tao, Zhang Jingxu, Fu Donghui, Chen Xiaoyun, and Liu Jie
Uniformity is an important index of the solar simulator, and the ellipsoid condenser plays an important role in solar simulator. Light energy emitted from the light source can be collected and aggregated on the second focal plane, and Gaussian energy distribution is formed by using the ellipsoid condenser. The uniformiUniformity is an important index of the solar simulator, and the ellipsoid condenser plays an important role in solar simulator. Light energy emitted from the light source can be collected and aggregated on the second focal plane, and Gaussian energy distribution is formed by using the ellipsoid condenser. The uniformity of the irradiated surface is directly determined by the distribution. A deformed ellipsoid condenser is obtained through ellipsoid equation Taylor expansion. The surface of the condenser can be deformed by 3 coefficients. The energy distribution on the second focal plane can be improved by the deformed ellipsoid condenser, and the uniformity of the solar simulator can be enhanced because of the weakened light energy contrast. An ellipsoid condenser used in a project is deformed and the deformed ellipsoid curve is obtained by using Matlab. The uniformity improvement on the second focal plane is proved by the simulation results of LightTools..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1223001 (2013)
Fabrication of Metamaterial Terahertz Devices by Semiconductor Laser Induced and Non-Electrolytic Plating with Copper
Wu Dongwei, Liu Jianjun, Li Huayue, Han Hao, and Hong Zhi
A method for fabricating metamaterial terahertz devices with laser induced and non-electrolytic plating with copper using a semiconductor laser (405 nm) is proposed. The line width of metal structure fabricated by the method is adjustable, the minimum metal width is 5 μm, and its thickness can be adjusted by copper plaA method for fabricating metamaterial terahertz devices with laser induced and non-electrolytic plating with copper using a semiconductor laser (405 nm) is proposed. The line width of metal structure fabricated by the method is adjustable, the minimum metal width is 5 μm, and its thickness can be adjusted by copper plating time. Moreover, a fabricated band-stop filter working in terahertz band is measured using terahertz time-domain spectrum. The result is in good agreement with finite-difference time-domain simulation. Fabricated quality of devices meet the design requirements. Fabrication of metamaterial terahertz devices by semiconductor laser induced and non-electrolytic plating possesses the advantages of low energy consumption, low equipment cost and high cost-effective as well..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1223002 (2013)
Physical Optics
Poincaré Sphere Representation for Vector Vortex Bessel-Gauss Beams
Jiang Yuesong, Zhang Xingang, Ou Jun, and Wen Donghai
A Poincaré sphere (PS) representation for states of polarization (SOPs) of vector vortex beams based on Jones matrix is proposed. For the vector vortex beams which are combined with two circular polarization optical vortexes of opposite topological charges, a distribution model of electric field vector is developeA Poincaré sphere (PS) representation for states of polarization (SOPs) of vector vortex beams based on Jones matrix is proposed. For the vector vortex beams which are combined with two circular polarization optical vortexes of opposite topological charges, a distribution model of electric field vector is developed by using Jones matrix. Two influencing factors of SOPs are educed: the topological charge and azimuthal angle. And the PS representation for SOPs with different topological charges is presented. Compared with the higher-order PS constructed with Stokes parameters, the physical meaning of this description method for vector vortex beams is much clearer. After a rigorous vector Helmholtz equation analysis, the amplitude of vector vortex beams is found to follow Bessel-Gauss distribution..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1226001 (2013)
Quantum Optics
Fluorescence Photon Correlation of a Three-Level Λ-Type Atom in a Squeezed Vacuum
Shi Wenxing, and Wang Fei
The fluorescence photon correlation in a three-level Λ-type atom in a broadband squeezed vacuum is investigated. By using the equation for the reduced density operator and the quantum regression theorem, the dynamics of the intensity correlation and the evolution are numerically calculated. The results show that the beThe fluorescence photon correlation in a three-level Λ-type atom in a broadband squeezed vacuum is investigated. By using the equation for the reduced density operator and the quantum regression theorem, the dynamics of the intensity correlation and the evolution are numerically calculated. The results show that the behavior of the photon correlation can obviously be modified by the squeezed vacuum. When the coherent field is so weak that the atomic coherence is negligible, the anticorrelation is preserved and the time for evolving into normal case is reduced via squeezed vacuum, and the populations of different levels are changed. However, when a stronger coupling field is applied, the combination of atomic coherence and squeezed vacuum leads to the changing from strong photon correlation to normal photon correlation, attributing to that the coherent population trapping is spoiled by the squeezed vacuum..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1227001 (2013)
Control of the Thermal Field with Time-Varying Frequency on Entropy Exchange in the J-C Model with Mixed States
Hu Yaohua, and Liu Qiang
Considering a two-level atom interacting with a single-mode thermal field, the reduced entropy change of the atom and the field with the sinusoidal and rectangular frequency modulations is studied by using quantum reduced entropy theory and numerical computation method. Results show that, for the sinusoidal modulation,Considering a two-level atom interacting with a single-mode thermal field, the reduced entropy change of the atom and the field with the sinusoidal and rectangular frequency modulations is studied by using quantum reduced entropy theory and numerical computation method. Results show that, for the sinusoidal modulation, the evolution of the entropy increments of the atom and the field presents periodic collapse and revival phenomena with large amplitude of the frequency change. For the rectangular frequency modulation, the intensity of entropy exchange between the atom and the field weakens significantly when the pulse strength increases. For both of the modulations, the entropy exchange between the atom and the field always occurs..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1227002 (2013)
Entanglement Properties in the System of Atom Interacting with Two-Mode Cavity
Lu Daoming, and Qiu Changdong
System of a two-level atom interacting with two-mode cavity is considered in which two modes are coupled. Negativity is used to quantify the degree of entanglement. By means of numerical calculations, the evolution of the entanglement between atom and field or between two modes is investigated. The influence of couplinSystem of a two-level atom interacting with two-mode cavity is considered in which two modes are coupled. Negativity is used to quantify the degree of entanglement. By means of numerical calculations, the evolution of the entanglement between atom and field or between two modes is investigated. The influence of coupling coefficient between two modes on the entanglement is discussed. The results show that the entanglement between atom and field or that between two modes displays periodic evolution, and its period is decreased with the increase of coupling coefficient between two modes. The entanglement between atom and field has a nonlinear relation with the increase of coupling coefficient between two modes. The entanglement between two modes is weakened with the increase of coupling coefficient between two modes..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1227003 (2013)
Remote Sensing and Sensors
Research on Spatial Wave-Front Characteristics of the Inner Optical Fields of the Transmitter with Double-Face Rotatable Reflectors in Down-Looking Synthetic Aperture Imaging Ladar
Ma Xiaoping, Sun Jianfeng, Lu Zhiyong, Zhou Yu, Zhi Yanan, Xu Qian, and Liu Liren
In down-looking synthetic aperture imaging ladar (SAIL), spatial parabolic wave-front phase differences are requested for two coaxial reverse scanned polarization-orthogonal beams at the rear focal plane of inner optical fields of the transmitter. Using self-heterodyne detection and phase complex-value processing, thisIn down-looking synthetic aperture imaging ladar (SAIL), spatial parabolic wave-front phase differences are requested for two coaxial reverse scanned polarization-orthogonal beams at the rear focal plane of inner optical fields of the transmitter. Using self-heterodyne detection and phase complex-value processing, this kind of SAIL generates a linear phase modulation proportional to the lateral distance in the orthogonal direction, and a parabolic phase history concerted in longitudinal position of the target point in the travel direction, based on the imaging principles of Fourier transformation focus and two-order phase matched filtering, respectively. The novel rotatable structure with double-face reflectors is proposed, in order to make two coaxial polarization-orthogonal beams scan far field target with different directions and the same angular rate in the orthogonal direction. And then, cylinder lens is employed in one of polarization branches to control phase change of the travel direction beam. According to the theory of Fourier optics and mathematical approximation, the effect of the positions of double-face rotatable reflectors on the distribution of inner optical field is studied by theoretical analysis and formula derivation. Under physical model constructed, the diffraction of two coaxial polarization-orthogonal beams from laser to inner optical fields is simulated numerically. The comparison results of amplitude and wave-front phase distribution between the discrete simulation and formula analysis are given, and finally, error analysis and conclusions are obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1228001 (2013)
Study on Electrically Tunable Shack-Hartmann Wavefront Sensor Based on Liquid Crystal
Li Hui, Wu Yuntao, Pan Fan, Cai Dunbo, and Zhang Yanduo
A 128 × 128 elements liquid crystal (LC) microlens array, instead of the conventional microlens array with a fixed focal length, is proposed to achieve an electrically controlled adaptive tunable Shack-Hartmann wavefront sensor. The sensor can overcome the shortcomings of the traditional wavefront sensor, which caA 128 × 128 elements liquid crystal (LC) microlens array, instead of the conventional microlens array with a fixed focal length, is proposed to achieve an electrically controlled adaptive tunable Shack-Hartmann wavefront sensor. The sensor can overcome the shortcomings of the traditional wavefront sensor, which can not take both measurement range and measurement accuracy into account, and it can work either in a large measuring range/short focal length, or high measurement accuracy/long focal length modes. It is also free to switch between the two modes. Through experimental measurements, when the operation mode of the wavefront sensor is on the short focal length, it has tunable focal length range of 86~400 μm. While the operating mode is on the focal length, its modulation transfer function is more than 0.46. The extreme experiment is used to verify its feasibility, which is about the focus falling outside the effective region of the CCD. The studies show that the wavefront sensor has a certain electronically controlled adaptive tunable ability. The potential application perspective of this design in an adaptive optics system is also presented..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1228002 (2013)
Effect of Radial Modes of Whispering Gallery Mode in Microtube
Jiang Junfeng, Zhang Jing, Liu Tiegen, Liu Kun, Yu Zhe, Zhang Xuezhi, Liu Wenhui, and Chen Wenjie
Effects of the radial modes of electric field in micrtube on detection sensitivity of whispering gallery mode (WGM) based opto-fluidic biosensor are theoretically analyzed. By increasing the incident angle of the prism, different radial modes are excited in experiment through the prism coupling method. The sensitivity Effects of the radial modes of electric field in micrtube on detection sensitivity of whispering gallery mode (WGM) based opto-fluidic biosensor are theoretically analyzed. By increasing the incident angle of the prism, different radial modes are excited in experiment through the prism coupling method. The sensitivity of the sensor with different radial modes is measured by sensing experiments using ethanol solution of different mass fractions. The results show that sensitivity is obviously affected by radial modes. The sensitivity is enhanced from 2.725 nm/RIU (refractive index unit) to 24.464 nm/RIU when the radial mode increases from 28 to 38, which is consistent with the theoretical analysis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1228003 (2013)
Frequency Scaling Algorithm for Synthetic Aperture Ladar Imaging with Wide-Scene
Li Xiaozhen, Wu Yufeng, Guo Liang, and Zeng Xiaodong
Due to the short wavelength of the signal in synthetic aperture ladar (SAL), the spot size is very small, which limits the imaging field. For this problem, the common wide-scene imaging mode in synthetic aperture radar (SAR), i.e., the TOPS imaging mode, is extended and applied in SAL, and according to the signal charaDue to the short wavelength of the signal in synthetic aperture ladar (SAL), the spot size is very small, which limits the imaging field. For this problem, the common wide-scene imaging mode in synthetic aperture radar (SAR), i.e., the TOPS imaging mode, is extended and applied in SAL, and according to the signal characteristic of SAL, a suitable imaging algorithm is proposed. The azimuth pre-filtering based on the spectrum analysis is adopted to eliminate the aliasing caused by the steering of the antenna beam and the signal spectrum without alias is obtained. The improved frequency scaling algorithm (FSA) is used to complete the range compression and range cell migration correction. Also, the Doppler frequency shift induced by the continuous movement of the platform is compensated. With the dechirp technique, the signal is focused in the Doppler domain and the SAL image without blurring is obtained. Simulation results are provided to demonstrate the effectiveness of the proposed method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1228004 (2013)
Scattering
Optimal Fitting Cumulants Method for Dynamic Light Scattering
Liu Wei, Wang Yajing, and Shen Jin
Dynamic light scattering is a powerful tool for measuring the size of nanoscale particles. However, the average particle size inverted by the traditional linear cumulants method depends closely on the length of correlation data. Linear and non-linear fitting algorithms are analyzed in order to overcome this disadvantagDynamic light scattering is a powerful tool for measuring the size of nanoscale particles. However, the average particle size inverted by the traditional linear cumulants method depends closely on the length of correlation data. Linear and non-linear fitting algorithms are analyzed in order to overcome this disadvantage. An optimized fitting algorithm for the cumulants method is proposed based on the advantages of both fitting algorithms. The particle diameter is obtained from a first-order curve fit, and the particle distribution′s polydispersity from a second-order polynomial fit over the optimal range of the intensity correlation function. Theoretical analysis and experimental data show that the relative error and repeatability of the inverted diameter are less than 2%, and the relative error of polydispersity index is less than 6%. In conclusion, the optimal fitting algorithm for the cumulants method can be used to measure a stable and reliable particle size and its polydispersity index..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1229001 (2013)
Simulating the Light Absorption and Scattering Properties of Microcystis Aeruginosa Using a Two-Layered Spherical Geometry
Lü Heng, Dai Hongliang, Li Yunmei, Li Xiaojun, Wang Yu, Pan Hongzhou, and Zhang Jie
Microcystis aeruginosa is the main species during alga bloom in inland eutrophic lakes. We consider that Microcystis aeruginosa consists of cytoplasm and chloroplast for simulating optical characteristics based on the two-layered spherical geometry. The central real refractive index value and volume ratio of chloroplasMicrocystis aeruginosa is the main species during alga bloom in inland eutrophic lakes. We consider that Microcystis aeruginosa consists of cytoplasm and chloroplast for simulating optical characteristics based on the two-layered spherical geometry. The central real refractive index value and volume ratio of chloroplast are calculated through the method of loop iterations. Meanwhile, based on the Kramers-Kronig relationship, the refractive index value of cytoplasm and chloroplast could be obtained. Finally, the absorption and scattering properties of Microcystis aeruginosa are simulated using the Aden-Kerker theory and particle size distribution. The results show that the relative errors between modeled and measured scattering and absorption efficiency factors are 3.4% and 4.3%, respectively. In comparison with the simulation based on Mie theory, the two-layered spherical model shows a better simulation accuracy of the backscattering properties..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1229002 (2013)
Spectroscopy
Measurements of Gas Temperature and Component Concentration Based on Calibration-Free Wavelength-Modulation Spectroscopy
Qu Dongsheng, Hong Yanji, Wang Guangyu, and Pan Hu
The gas temperature and component concentration can be measured according to the iteration using the calibration-free wavelength-modulation spectroscopy based on the tunable semiconductor laser. The parameters required in the experiment and simulation can be obtained after measuring the laser modulation parameters of tThe gas temperature and component concentration can be measured according to the iteration using the calibration-free wavelength-modulation spectroscopy based on the tunable semiconductor laser. The parameters required in the experiment and simulation can be obtained after measuring the laser modulation parameters of two H2O absorption lines (7185.60 cm-1 and 7454.45 cm-1). Frequency division multiplexing technology is adopted to measure gas temperature and component concentration of the gas temperature field in the temperature range of 600 K~1000 K. Experimental results show that the measured gas temperature and component concentration using the calibration-free wavelength-modulation spectroscopy are consistent with the predicted values. Compared with the temperature measured by thermocouple and the component concentration measured by direct absorption spectrum method, the most relative errors are within 4% and 5%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1230001 (2013)
Thin Films
Influence of Laser Conditioning on the Damage Properties of HfO2 Thin Film
Yang Lihong, Wang Tao, Su Junhong, and Han Jintao
The effects of different laser fluences on the optical properties of HfO2 thin films mainly including damage threshold and damage morphology, are studied under 1-on-1 condition. In experiment, the energies of 10%, 30%, 50% and 70% of the threshold energy are used to condition the HfO2 films in 1-on-1 mode. After conditThe effects of different laser fluences on the optical properties of HfO2 thin films mainly including damage threshold and damage morphology, are studied under 1-on-1 condition. In experiment, the energies of 10%, 30%, 50% and 70% of the threshold energy are used to condition the HfO2 films in 1-on-1 mode. After conditioning, the surface roughness decreases from 2.62 nm to 2.41 nm. With the energy increasing, the transmittance at 1064 nm is enlarged with conditioning. The damage threshold is increased firstly, and then decreases. When the energy is 30% of the threshold energy, the damage threshold reaches the maximum value of 26.86 J/cm2 and increases by 56%. Comparing the damage morphology between conditioning and without conditioning, after the film is conditioned with 30% of the threshold energy, the damage depth under 140 mJ laser irradiation decreases from 98 nm without conditioning to 30 nm and the damage spot number decreases from 5 to 1. The experiment result shows that inclusions are the main factors of threshold decrease and conditioning with low laser fluences has the effect of decreasing the defects and solidifying the film, thus it can improve the laser-damaged threshold of films..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1231001 (2013)
Fabrication and Optical Properties of Vanadium Dioxide Thin Films Doped by Tungsten-Vanadium Co-Sputtering
Qin Yuan, Li Yi, Fang Baoying, Tong Guoxiang, Wang Xiaohua, Ding Jie, Wang Feng, Yan Meng, Liang Qian, Chen Shaojuan, Chen Jiankun, Zheng Hongzhu, and Yuan Wenrui
In order to reduce high phase transition temperature and improve low transmittance contrast in the infrared (IR) region before and after phase transition caused by doping, W-doped VO2 thin films with an obvious thermochromic behavior are fabricated by W-V co-sputtering on the glass substrates and annealed in a mixture In order to reduce high phase transition temperature and improve low transmittance contrast in the infrared (IR) region before and after phase transition caused by doping, W-doped VO2 thin films with an obvious thermochromic behavior are fabricated by W-V co-sputtering on the glass substrates and annealed in a mixture of N2 and O2. Component and structure of VO2 thin films oxidized in different ratios of N2-O2 mixture are analyzed. Results reveal that VO2 grows in preferential crystal orientations along (011) and (200), and the particle dimension increases from 50 nm to 80 nm as O2 content rises. Phase transition temperature of W-doped VO2 thin films reduces to 31 ℃, transmittance contrast in the IR region before and after phase transition is 41%. Results demonstrate that proper W-doped concentration can reduce the phase transition temperature, improve IR transmittance spectrum and gently change the transmittance contrast..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1231002 (2013)
Design and Preparation of ITO Film Filter Used in Thermal Photovoltaic System
Yang Huiyin, Chen Xue, and Qian Ziqing
Indium tin oxide (ITO) semiconductor film is a typical wide bandgap semiconductor material. It owns much peculiarity, such as higher transmissivity in the short wavelength, higher reflectivity in the long wavelength, and super-wide reflection band, which meet the requirement of thermal photovoltaic (TPV) system. The opIndium tin oxide (ITO) semiconductor film is a typical wide bandgap semiconductor material. It owns much peculiarity, such as higher transmissivity in the short wavelength, higher reflectivity in the long wavelength, and super-wide reflection band, which meet the requirement of thermal photovoltaic (TPV) system. The optical properties of ITO film are calculated with the parameters of carrier concentration, mobility and thickness. The spectral curves of filters are given according to different parameters. The ITO film is prepared by using magnetron sputtering deposition technology. The optical properties of filters are given, and the ITO filter used in TPV system is prepared after anneal. The cut off wavelength of prepared filter matching with GaSb cell is 2 μm, the average transmissivity of short-wave band approaches 70%, the average reflectivity of long-wave band approaches 70%, and the ultra-wide reflection band extends to 10 μm, which can improve the efficiency of TPV system greatly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1231003 (2013)
Vision, Color, and Visual Optics
Objective Evaluation of Flicker in Stereoscopic Display with Active Shutter Glasses
Xia Zhenping, Li Xiaohua, Chen Lei, and Tang Sihai
To evaluate the flicker visibility of active shutter type stereoscopic display more precisely and objectively, the temporal luminance response signal measurement based flicker visibility objective evaluation method is proposed. The temporal luminance measurement system realizes the precise record of display luminance oTo evaluate the flicker visibility of active shutter type stereoscopic display more precisely and objectively, the temporal luminance response signal measurement based flicker visibility objective evaluation method is proposed. The temporal luminance measurement system realizes the precise record of display luminance output. Based on the critical flicker frequency (CFF) model of cathode ray tube (CRT) display, the perception experiments on stereoscopic display with active shutter glasses are implemented to establish the flicker visibility objective evaluation model of stereoscopic display with active shutter glasses. The correlation coefficient between the estimation result of the proposed model and the perception result is 0.97. The temporal luminance measurement system combined with the flicker visibility estimation model realizes the objective evaluation of the flicker in stereoscopic display with active shutter glasses, and it also helps to optimize the visual comfort level of stereoscopic displays..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1233001 (2013)
X-Ray Optics
Carbon Contamination Modeling on Extreme Ultraviolet Optic Surfaces
Lu Guoqing, Lu Qipeng, Peng Zhongqi, and Gong Xuepeng
In order to estimate and predict the carbonaceous contamination of extreme ultraviolet (EUV) multilayer optical element surfaces caused by EUV irradiation in the presence of residual hydrocarbon gases, a comprehensive model of radiation-induced carbon growth on EUV optic surfaces is presented. The model describes the tIn order to estimate and predict the carbonaceous contamination of extreme ultraviolet (EUV) multilayer optical element surfaces caused by EUV irradiation in the presence of residual hydrocarbon gases, a comprehensive model of radiation-induced carbon growth on EUV optic surfaces is presented. The model describes the transport of residual hydrocarbons to the irradiated area and the subsequent dissociation of the hydrocarbon by both EUV ionization and secondary electron excitation. The dissociated hydrocarbons are reactive and form a carbonaceous film. Model predictions fit experimental data quite well. Theoretical analysis indicates that the primary cause of hydrocarbon dissociation is bond breaking by direct photon absorption rather than by secondary electrons. Calculations also demonstrate that the growth of carbon film depends on various conditions of hydrocarbon partial pressure and EUV power. The model successfully predicts that light hydrocarbons (<～100 amu) pose a negligible risk to EUV optics and modest increases in substrate temperature (~30 ℃), which will substantially reduce optic contamination by increasing hydrocarbon desorption from the surface..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1234001 (2013)
X-Ray Phase Contrast Micro-Tomography and Its Application in Quantitative 3D Imaging Study of Wild Ginseng Characteristic Microstructures
Ye Linlin, Xue Yanling, Tan Hai, Chen Rongchang, Qi Juncheng, and Xiao Tiqiao
In situ non-destructive imaging of characteristic microstructures of wild ginseng are investigated by synchrotron radiation X-ray propagation-based phase-contrast computed tomography (PPCT), and phase-attenuation duality Paganin algorithm (PAD-PA), a phase retrieval algorithm, is employed to process the experimental PPIn situ non-destructive imaging of characteristic microstructures of wild ginseng are investigated by synchrotron radiation X-ray propagation-based phase-contrast computed tomography (PPCT), and phase-attenuation duality Paganin algorithm (PAD-PA), a phase retrieval algorithm, is employed to process the experimental PPCT data, and the three-dimensional imaging of wild ginseng, such as the quantitative volume, the region and number distributions of calcium oxalate are obtained. The results show that PPCT combines with PAD-PA phase retrieval algorithm is well suit for quantitative study and analysis of microstructures of traditional Chinese medicines like wild ginseng..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 12, 1234002 (2013)
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