Contents
2015
Volume: 35 Issue 3
52 Article(s)
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Atmospheric Optics and Oceanic Optics
Optimal Design of the Telescope in Coherent Lidar and Detection Performance Analysis
Jia Xiaodong, Sun Dongsong, Shu Zhifeng, Zhang Feifei, and Xia Haiyun
A fiber laser with pulse energy of 110 mJ, pulse repetition frequency of 20 kHz and pulse width of 300 ns is employed to develop the coherent lidar for wind sensing at 1.55 mm. The specifications of the main components employed to assemble the lidar are listed. By taking the advantage of the principle of backpropagatedA fiber laser with pulse energy of 110 mJ, pulse repetition frequency of 20 kHz and pulse width of 300 ns is employed to develop the coherent lidar for wind sensing at 1.55 mm. The specifications of the main components employed to assemble the lidar are listed. By taking the advantage of the principle of backpropagated local oscillator (BPLO), the optimal truncation ratio of the telescope is calculated. The result shows that the optimal antenna efficiency of 0.422 is obtained when the truncation ratio arrives at 0.823. The effect of the aperture of the telescope on the carrier-to-noise ratio (CNR) of the coherent lidar is analyzed on the condition of the optimal truncation ratio. The design parameters of the telescope are optimized. The performance of the lidar is theoretically calculated and listed as follows: detection range is longer than 3 km; wind velocity range is ± 62 m/s; range resolution is 84 m; wind velocity accuracy is better than 0.1 m/s; time resolution is 0.5 s..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 301001 (2015)
Retrieval of Aerosol Extinction Coefficient and Optical Thickness Using Varied Lidar Ratio
Bao Qing, He Junliang, and Zha Yong
Lidar plays an important role in monitoring atmospheric aerosol for its high vertical spatial and temporal resolution. During the process of inversing aerosol extinction coefficient and optical depth by Fernald method, Lidar ratio is the main error source. However, in the present application, Lidar ratio is commonly taLidar plays an important role in monitoring atmospheric aerosol for its high vertical spatial and temporal resolution. During the process of inversing aerosol extinction coefficient and optical depth by Fernald method, Lidar ratio is the main error source. However, in the present application, Lidar ratio is commonly taken as a fixed value, which may inevitably bring a certain amount of errors to the retrieval from Lidar measurement. An estimating model to calculate varied Lidar ratio through the stepwise regression analysis of pollutant data, meteorological data and Lidar data is established. The study shows that Lidar ratio has significant correlation with PM2.5 mass concentration, relative humidity and the mass concentration of SO2 and NO2. Compared to the fixed value, the usage of varied Lidar ratio can significantly improve the inversion accuracy of aerosol extinction coefficient and optical depth..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 301002 (2015)
Fast Radiance Calibration for Ground-Based Large-Aperture Infrared Opto-Electric Equipment
Liu Junchi, Li Hongwen, Wang Jianli, and Yin Limei
In the multi-target observations using the ground-based large-aperture infrared telescope, in order to eliminate the influence of changing the system radiance responsivity caused by environment, and calibrate the radiance responsivity in short time during two observations, a fast radiance calibration method is discusseIn the multi-target observations using the ground-based large-aperture infrared telescope, in order to eliminate the influence of changing the system radiance responsivity caused by environment, and calibrate the radiance responsivity in short time during two observations, a fast radiance calibration method is discussed. A mathematical model and experimental procedures are set up. The radiance responsivity is calibrated, and the atmospheric transmittance is measured, based on the standard infrared stars. The illuminance of stars is inversed, which is known in advance, using the calibrated data. Data shows that the maximum relative error of inversion is 18.93% and it takes about 4 min to complete the experiment. As a comparison, the maximum relative error is 28.74%, and it takes about 17 min to complete the experiment, using the traditional method, that the radiance respoinsivity is calibrated based on the black body, and the atmospheric transmittance is calculated by Modtran. Results show that, compared with the traditional method, it takes less time to complete the experiment, and the relative error of illuminance inversion is smaller. The black body is not necessary, and it takes less cost..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 301003 (2015)
Diffraction and Gratings
Study of Secondary Peak of Polarization Dependent Loss of Locally Pressed Fiber Bragg Grating
Su Yang, Zhou Hua, Zhu Yong, and Li Jianhua
The spectral characterization of polarization dependent loss (PDL) of locally pressed fiber Bragg grating is analyzed. Aimed at secondary peak phenomenon, the effects of the load magnitude, loaded length and loaded position of the grating on the amplitude and position of the created secondary peak are investigated in dThe spectral characterization of polarization dependent loss (PDL) of locally pressed fiber Bragg grating is analyzed. Aimed at secondary peak phenomenon, the effects of the load magnitude, loaded length and loaded position of the grating on the amplitude and position of the created secondary peak are investigated in detail. The numerical simulation based on the modified transfer matrix method is carried on. The theoretical analysis and numerical simulation demonstrate that the loaded length has significant effect on the amplitude and sensitivity of wavelength shifting as function of loaded amplitude of the secondary peak. The load amplitude of creating secondary peak changes under the different loaded lengths. These studies have a good theoretical guidance meaning for sensing using secondary peak of PDL..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 305001 (2015)
Study of Gratings Tiled by Holographic Exposure with Wave Aberration
Qian Guolin, Wu Jianhong, Li Chaoming, Chen Xinrong, and Zou Wenlong
Large-aperture pulse compression gratings are needed by laser confinement fusion system. Tiled-grating made by holographic exposure is an important way to manufacture large aperture gratings. A method is proposed to align the gratings for the exposure system with wave aberration. In order to study the effect of the wavLarge-aperture pulse compression gratings are needed by laser confinement fusion system. Tiled-grating made by holographic exposure is an important way to manufacture large aperture gratings. A method is proposed to align the gratings for the exposure system with wave aberration. In order to study the effect of the wave aberration on the characteristics of tiled-grating, the random wave fronts are used to simulate the tiled-gratings. The relationship between the distribution of far-field diffraction energy and the tiling-error is calculated. A grating of (150+150)×200 mm2 is made experimentally. The root-mean-square value of the tiling-error is 0.034λ and the peak to peak value is 0.110λ. The ± 1st diffraction wave fronts of the grating are used to calculate wave aberration of the exposure system. The minimum value of the tiling-error is simulated theoretically. The root-mean-square value of the error is 0.016λ and the peak to peak value is 0.105λ. The results show that the tiling-error is close to the simulated data. The far-field diffraction intensity can not be decreased obviously by the tiling-error. It is proved that the method proposed in this article is feasible..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 305002 (2015)
Axial Two Focus Zone Plate under Tight Foucsing Conditions
Ji Shengzhe, Zhu Linwei, Sun Meiyu, Wang Lili, and Li Zhigang
An analytic formula of the radius of a zone plate is deduced by the vector diffraction theory under the tight-focusing conditions. Based on the binary phase zone plate designed by the formula, axial two focuses can be created in the focusing area of a high numerical aperture (NA) objective lens. Because the formula of An analytic formula of the radius of a zone plate is deduced by the vector diffraction theory under the tight-focusing conditions. Based on the binary phase zone plate designed by the formula, axial two focuses can be created in the focusing area of a high numerical aperture (NA) objective lens. Because the formula of the radius of the zone plate is related to the axial shifting distance of the two focuses, it is possible to design a set of zone plates with different axial shifting distances for generating tunable axial two focuses. For a high NA objective illuminated by a radial polarized Bessel- Gaussian light, the field distributions of the objective modulated by the binary zone plate with different axial shifting distances are simulated. It is shown that axial tunable two focuses can be realized successfully. In addition, using the zone plate with suitable axial distance, some special focusing fields, such as“optical bubble”and“optical needle”can also be realized under the tightfocusing condition. Hence, such binary zone plates could be utilized for optical trapping and manipulation of particles..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 305003 (2015)
Fiber Optics and Optical Communications
All-Optical Clock Extraction Based on Injection-Locked Semiconductor Laser
Ma Chuang, Jiang Yang, Jia Shi, Bai Guangfu, Hu Lin, Shan Yuanyan, Liang Jianhui, Li Hongxia, and Yu Jinlong
A scheme of all-optical clock extraction based on injection locked semiconductor laser is proposed and demonstrated. In the scheme, optical carrier and one clock component of return-to-zero (RZ) signal lock two semiconductor lasers to obtain the phase locked optical outputs. When these two components are coupled togethA scheme of all-optical clock extraction based on injection locked semiconductor laser is proposed and demonstrated. In the scheme, optical carrier and one clock component of return-to-zero (RZ) signal lock two semiconductor lasers to obtain the phase locked optical outputs. When these two components are coupled together, the recovery clock signal is achieved. Two distributed feedback (DFB) lasers are used to extract the clock signal of a 10 Gb/s RZ signal experimentally. This scheme is very flexible in dynamic range of injected power, tunability and stability requirements of signal wavelength. This novel technique also has potential in integration and practicability..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 306001 (2015)
Channel Characterization Parameters of the Non-Empty Indoor Visible Light Communication Based on the Three-Dimension Ray Tracing and Finite State Markov Chain
Deng Lijun, and Fan Yangyu
By the means of three-dimension ray tracing method, the channel impulse response under the nonempty indoor visible light transmission environment and the root-mean-square (RMS) delay spread when light source locates in different positions of the ceiling are estimated. Based on this, the finite state Markov chain is useBy the means of three-dimension ray tracing method, the channel impulse response under the nonempty indoor visible light transmission environment and the root-mean-square (RMS) delay spread when light source locates in different positions of the ceiling are estimated. Based on this, the finite state Markov chain is used to model the indoor visible light fading channel, and the distribution of the non-empty indoor visible light channel impulse response is obtained. The results demonstrate that random distribution reflector imposes greater effects on the channel impulse response in the non- line of sight (NLOS) transmission environment than that in the line of sight (LOS) situation. Besides, the RMS delay spread is obvious when the light source locates at the corner of the ceiling instead of other positions, which means that the multipath effect is more obvious at this place..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 306002 (2015)
Fiber Bragg Grating Electrostatic Voltage Sensor Based on Uniform Strain Beam
Zhang Kaiyu, Zhao Hong, Zhang Weichao, Chen Junqi, and Zhang Yindong
In order to achieve high precise measurements of electrostatic voltmeter, an electrostatic voltage sensor of fiber Bragg grating (FBG) based on uniform strain beam is proposed. It can achieve temperature selfcompensation of sensor by twin- FBG structure scheme in a special temperature range; the sensor structure systemIn order to achieve high precise measurements of electrostatic voltmeter, an electrostatic voltage sensor of fiber Bragg grating (FBG) based on uniform strain beam is proposed. It can achieve temperature selfcompensation of sensor by twin- FBG structure scheme in a special temperature range; the sensor structure system is optimumly designed and prepared by simulation analysis of uniform strain beam and simulation on electric field of sensor system. Uniform electric field is produced using a pair of plate electrode, conductor hemisphere is forced under the pull of electrostatic force and the shape of uniform strain beam is deformed, causing central wavelength of twin- FBG reflection spectrum shift, and realizing the voltage measurement by wavelength difference of FBG. The experimental results show that the sensor can measure direct current (DC) and alternating current (AC) root- mean- square voltages from 5 kV to 24 kV. Moreover, the measurement accuracy is 2.1% from 5 kV to 12 kV and 0.89% from 12 kV to 24 kV, and the fitting degree of the sensing curves is 0.99985. The sensor satisfies the requirement of high stability and high reliability, high precision and strong anti-interference ability and so on..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 306003 (2015)
Image Processing
Distributed Near Lossless Compression of Hyperspectral Images
Tang Yi, Wan Jianwei, and Nian Yongjian
The efficient compression of onboard hyperspectral images has been a difficult problem which needs to be resolved urgently. Low encoding complexity and excellent error resilience are provided by distributed source coding, which has wide applied foreground in the field of hyperspectral images compression. For the probleThe efficient compression of onboard hyperspectral images has been a difficult problem which needs to be resolved urgently. Low encoding complexity and excellent error resilience are provided by distributed source coding, which has wide applied foreground in the field of hyperspectral images compression. For the problem of onboard compression for hyperspectral images, a distributed near lossless compression algorithm based on multi- level coset codes is proposed. According to the procedure of Slepian- Wolf lossless coding based on multi- level coset codes, an optimal quantization scheme for distributed near lossless compression of hyperspectral images is presented, which makes the distortion of hyperspectral images minimum under the given target bit-rates. Slepian-Wolf lossless coding is performed on the quantized values, which realizes the distributed near lossless compression of hyperspectral images. Experimental results show that the proposed algorithm can obtain both high near lossless compression performance and low encoding complexity compared with those existed classical algorithms..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 310001 (2015)
Image Enhancement in Non-Subsampled Contourlet Transform Domain Based on Multi-Scale Retinex
Wu Yiquan, and Shi Junpeng
Aiming at the problem of contrast deficiency and low luminance in some remote sensing images and hyperspectral images, an enhancement method in non-subsampled contourlet transform (NSCT) domain based on multi-scale Retinex (MSR) and niche chaotic mutation particle swarm optimization (NCPSO) is proposed to improve the qAiming at the problem of contrast deficiency and low luminance in some remote sensing images and hyperspectral images, an enhancement method in non-subsampled contourlet transform (NSCT) domain based on multi-scale Retinex (MSR) and niche chaotic mutation particle swarm optimization (NCPSO) is proposed to improve the quality of images. Firstly, an image is decomposed through NSCT. A low-frequency component and several high-frequency components in different directions are produced. Then the low-frequency component is enhanced by the multi-scale Retinex algorithm with hybrid intensity transfer function. While the coefficients of high-frequency components are adjusted to enhance the edges by nonlinear gain function. The optimal parameters in the nonlinear gain function are searched by the niche chaotic particle swarm optimization algorithm, whose fitness is the integrated quantitative evaluation function considering both contrast and information entropy. A large number of experimental results show that, compared with four enhancement methods such as histogram double equalization method, non-subsampled contourlet transform method, multi-scale Retinex method and stationary wavelet transform and Retinex method, the proposed method can improve the contrast and information entropy more efficiently, and enhances the whole visual effects..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 310002 (2015)
Research on the Contrast Enhancement Algorithm of Synchrotron Radiation X-Ray Image
Liang Chuanhui, Wang Yudan, Du Guohao, Deng Biao, Xie Honglan, and Xiao Tiqiao
In the process of synchrotron radiation X- ray imaging, the X- ray image with lower or uneven contrast is obtained invariably, this causes some details of the sample in the image are difficult to observe and analyze. In order to solve the problem, a new algorithm is proposed to enhance the X- ray image and get a higherIn the process of synchrotron radiation X- ray imaging, the X- ray image with lower or uneven contrast is obtained invariably, this causes some details of the sample in the image are difficult to observe and analyze. In order to solve the problem, a new algorithm is proposed to enhance the X- ray image and get a higher contrast. The algorithm is based on homomorphic filtering, and combined with image denoising pretreatment and gray level adjustment, so that the contrast can be enhanced and the image quality can be improved simultaneously. Furthermore, the algorithm is realized by writing program, and the X- ray images of a resolution target and marine fish are utilized to test the performance of the proposed algorithm. The results show that the proposed algorithm can well enhance the low contrast X-ray images with uneven distribution of gray level, and show the sample detail information more clearly, the gray level distributes more equably. Concurrently, the effect of X-ray image denoising is obvious..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 310003 (2015)
Imaging Systems
Influence Analysis on the Rolling Shutter for Time Delay and Integration in Digital Domain
Tao Shuping, and Jin Guang
Time delay and integration (TDI) in digital domain with the complementary metal-oxide-semiconductor (CMOS) sensor has low cost, low power consumption, flexible operation and other advantages, it has attracted much research attention in recent years. However, the rolling shutter of the CMOS sensor produces distortion foTime delay and integration (TDI) in digital domain with the complementary metal-oxide-semiconductor (CMOS) sensor has low cost, low power consumption, flexible operation and other advantages, it has attracted much research attention in recent years. However, the rolling shutter of the CMOS sensor produces distortion for imaging on moving object. In order to study the impact of the rolling shutter on TDI in digital domain, the mathematical model of image motion and modulation transfer function (MTF) decline induced by the rolling shutter effect on TDI in digital domain is established, combining with the principle of the rolling shutter. And the estimation analysis and confirmatory experiment are carried out combining with the derivation model. The results show that the rolling shutter bring a large affect on TDI in digital domain; the image motion gets larger and MTF declines more serious as the readout time gets longer; in addition, the influence gets more serious as the line period gets shorter, when the line period goes from 200 us to 100 us, the corresponding MTF of the images generated by TDI in digital domain decreases from 0.6144 to 0.4807..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 311001 (2015)
A Depth Resolution Enhancement Technique in Fourier Domain Optical Coherence Tomography
Guo Xin, Wang Xiangzhao, Nan Nan, and Li Zhongliang
A depth resolution enhancement technique in Fourier domain optical coherence tomography based on spectral shaping is proposed. Employing the spectral shape of light source itself, the detected frequency domain signal is reshaped to obtain the spatial signal with higher resolution. The theoretical analysis and simulatioA depth resolution enhancement technique in Fourier domain optical coherence tomography based on spectral shaping is proposed. Employing the spectral shape of light source itself, the detected frequency domain signal is reshaped to obtain the spatial signal with higher resolution. The theoretical analysis and simulations results show that the proposed technique can enhance the resolution for Gaussian and non Gaussian light sources..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 311002 (2015)
Instrumentation, Measurement and Metrology
Three-Dimensional Displacement Measurement in Solid Using Digital Volumetric Speckle Photography Based on Computer Tomography
[in Chinese], and Fu-pen Chiang
Digital volumetric speckle photography (DVSP) technique is proposed to measure three dimensional displacement in solid object. Using computer tomography (CT), magnetic resonance imaging (MRI), laser- scanning confocal microscopy (LSCM) or optical coherence tomography (OCT), three dimensional volumetric images of an objDigital volumetric speckle photography (DVSP) technique is proposed to measure three dimensional displacement in solid object. Using computer tomography (CT), magnetic resonance imaging (MRI), laser- scanning confocal microscopy (LSCM) or optical coherence tomography (OCT), three dimensional volumetric images of an object with speckle characteristics before and after deformation are abtained. These three dimensional images are divided into subsets with a certain voxel array and comparable. Afterwards three- dimensional fast Fourier transform (3D- FFT) is applied to a corresponding pair of subsets. A new resultant spectrum can be constructed by a numerical interference from the two procured spectra at the spectral domain. Then another step of 3D- FFT is performed on the resultant spectrum resulting an expanded impulse function whose displacement vector experienced by the speckles contained in the original subset as a whole. This process is carried out for every corresponding pair of subsets. By detecting the position of the crests of these impulse functions, an array of displacement vectors at all every subset is obtained and the 3D displacement fields are mapped. Using simulated 3D speckle volume images, the influences of speckle size, number, subset size, image contrast and image brightness on the accuracy and precision of DVSP are analyzed by digital experiments. We apply the DVSP technique to measure the internal 3D deformation field of red sandstone sample under uniaxial compression, and the resulting displacement and deformation field contours clearly indicate the damage characters of the sample..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 312001 (2015)
Thermal Design for a Kind of High-Light-Level Integrating Sphere Calibration Source
Sun Jingxu, and Zhang Hanzhuang
In order to meet laboratory radiometric calibration requirements for increasing optical aperture of optical remote sensors, a kind of high-light-level integrating sphere calibration source is designed based on near small source method. Meanwhile the optical and structural parameters of the high-light-level integrating In order to meet laboratory radiometric calibration requirements for increasing optical aperture of optical remote sensors, a kind of high-light-level integrating sphere calibration source is designed based on near small source method. Meanwhile the optical and structural parameters of the high-light-level integrating sphere calibration source are designed in detail. To solve the problem of heat dissipation of high-light-level integrating sphere calibration source, circulating cooling water is used as cooling means, and special cooling pipes are designed. The high-light-level integrating sphere calibration source is analyzed by finite element analysis method of thermal simulation in the state of 0.1 m/s of the circulating water. From the analysis results, the temperature around the tungsten bromine lamp is about 125 ℃ , the outlet temperature of the high-lightlevel integrating sphere calibration source is about 80 ℃ . From the experimental results, the temperature around the tungsten bromine lamp is about 125 ℃ , the outlet temperature of the high-light-level integrating sphere calibration source is about 100 ℃ . Through the comparative outlet temperature difference of the highlight-level integrating sphere calibration source, the causes are explained, and the validate of simulation analysis and theoretical calculations are verified. Meanwhile it can be suggested in the measurement data that the integrated spectral radiance of the high-light-level integrating sphere calibration source is 6714 W/(m2﹒sr) in the range of 400 nm to 900 nm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 312002 (2015)
Kinematic Coupling Design and Analysis for 30 m Telescope Tertiary Mirror System
Zhao Hongchao, Zhang Jingxu, Yang Fei, and Guo Peng
In order to avoid the introduction of aberrations which make the image quality degrade, both alignment and shift of the optical components are strictly guaranteed in the optical system. The kinematic interface has a wonderful performance in repeatability and low level of contact stress. So it is widely used in optical In order to avoid the introduction of aberrations which make the image quality degrade, both alignment and shift of the optical components are strictly guaranteed in the optical system. The kinematic interface has a wonderful performance in repeatability and low level of contact stress. So it is widely used in optical system. The thirty meter telescope (TMT) is an Ritchey-Chirtien (R-C) optical system. The tertiary mirror is employed to bend the light to the instruments. According to the requirement of the accuracy assembly this mirror is frequently removed to clean and recoat. So a kinematic interface is designed to meet the requirement. The study on the kinematic principle in positioning the rigid body is introduced. Then a preliminary design is constructed according with the mechanical principles. Thus the Hertz contact theory and IBM wear theory are employed to check the contact stress and the wear situation. At last, a positioning accuracy simulation is carried out by the Monte-Carlo method. In addition, a simulation is carried out to analyze the support performance in Ansys software. And some parameters is optimized. The results show that both the contact stress and the wear situation can meet the requirements. In addition, the repeatability in three directions and the support performance are achieved..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 312003 (2015)
Integrated Optics
Slow Light Effect of Coupled Waveguide with Eye-Shaped Scatterers
Wan Yong, Han Wenjuan, Jia Minghui, Yun Maojin, Guo Yue, and Sun Lei
Based on coupled waveguide with eye-shaped scatterer cavities with high-quality Q values, operations such as changing the parameters of the scatterers and changing those of the coupling cavities reveal the patterns about the variation of slow light effect on photonic crystal coupled waveguide and can achieve very high Based on coupled waveguide with eye-shaped scatterer cavities with high-quality Q values, operations such as changing the parameters of the scatterers and changing those of the coupling cavities reveal the patterns about the variation of slow light effect on photonic crystal coupled waveguide and can achieve very high group index within the flat band. Simulations prove that regardless of the number of coupling cavities, slow light with decent flat band and structures with ultra-slow light and group index between 4.10×104 and 1.35×105 can be achieved by adjusting the ratio of the major axis to the minor axis and by shifting the scatterers..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 313001 (2015)
Design and Analysis of Photorefractive Long-Period Waveguide Grating Coupler
Zhang Ming, Ren Jianwen, Chen Wen, and Le Zichun
To obtain an easily made grating coupler with stable materials, a proposal to fabricate photorefractive long- period gratings coupler on Ti- diffused LiNbO3 waveguide is presented. Structural parameters of the coupler can be determined by using effective index method and coupled- mode theory, including grating period aTo obtain an easily made grating coupler with stable materials, a proposal to fabricate photorefractive long- period gratings coupler on Ti- diffused LiNbO3 waveguide is presented. Structural parameters of the coupler can be determined by using effective index method and coupled- mode theory, including grating period as 74.28 mm, separation distance of two waveguides as 8 mm and the minimum grating length for 100% coupling as 2.42 cm. The transmission spectrum is analysed and the 3-dB bandwidth can reach 5.20 nm. The simulation results also show that coupling efficiency is above 90% when tolerance of grating length and offset distance is 0.37 cm and 0.21 cm, respectively. The coupler is expected to be used in coarse wavelength division multiplexing system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 313002 (2015)
Lasers and Laser Optics
Performance Analysis of Laser Transmitting System for Fourier Telescope
Luo Xiujuan, Zhang Yu, Gao Cunxiao, Ren Juan, Cao Bei, Liu Hui, and Chen Minglai
The performance of Fourier telescope transmitting system directly affects the image resolution and quality. The parameters and performance requirements of laser are analyzed. The design outline of fiber laser is presented. Meanwhile, the point is put forward that the laser coherence length need to be at least 1.6 timesThe performance of Fourier telescope transmitting system directly affects the image resolution and quality. The parameters and performance requirements of laser are analyzed. The design outline of fiber laser is presented. Meanwhile, the point is put forward that the laser coherence length need to be at least 1.6 times of the residual optical path. The stability of laser power and frequency is simulated. To ensure the stability of the laser, some methods are put forward from the points of design, algorithm and practice. Furthermore, combined with the results of simulation and experiment, the influences of the transmitter performance on image quality is analyzed, from the aspects of transmitting aperture layout, aperture amount, position precision and the beam pointing error. And point out that baseline redundancy, image resolution, target spectrum and image quality are the factors should be synthetically considered when arranging transmitter array. The formula for calculating the number of transmitting apertures is obtained based on the two- dimensional sampling theorem and the statistical analysis results. The transmitting aperture number is calculated for the Fourier telescope whose resolution would be 5 cm for objects in 1000 km low earth orbit. In addition, it is concluded that the transmitting aperture position error should be less than 5% of the minimum aperture spacing..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 314001 (2015)
Adaptive Frequency Stabilization Technique for Total Reflection Prism Laser Gyros
Ma Jiajun, Jiang Junbiao, and Liu Jianning
For the phase-sensitive signal of the total reflection prism laser gyros (TRPLG) is subjected to noise interference phenomenon during in frequency stabilization, a novel technique for the adaptive frequency stabilization of TRPLG is studied. The theory of frequency stabilization characteristic of the TRPLG is analyzed,For the phase-sensitive signal of the total reflection prism laser gyros (TRPLG) is subjected to noise interference phenomenon during in frequency stabilization, a novel technique for the adaptive frequency stabilization of TRPLG is studied. The theory of frequency stabilization characteristic of the TRPLG is analyzed, combined with the principle of adaptive noise cancellation, a mathematic model of the adaptive frequency stabilization system in TRPLG is proposed. The control system based on recursive least square method for the adaptive frequency stabilization of TRPLG is built by the hardware circuit design. The experimental tests for the original frequency stabilization technique and adaptive frequency stabilization technique are conducted. The results show that, using adaptive frequency stabilization technique, the performance of phase-sensitive signal subjected to noise interference could be eliminated effectively and frequency stabilization accuracy is improved by nearly an order of magnitude, the gyros accuracy could be improved by over 60% . The analytic study provides an important reference for improving the performance of TRPLG..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 314002 (2015)
Study of Ultra-Intense Laser Driven Solid Line Emitting Terahertz Wave
Li Xinghuo, Zhuo Hongbin, and Zou Debin
The ultra-intense terahertz radiation from laser plasma interaction is widely studied. The terahertz radiation from ultra- intense laser pulse driven wire target is studied by using the radiation theory of antenna proposed by Smith. The expressions of the radiation field are obtained and the space radiation field and fThe ultra-intense terahertz radiation from laser plasma interaction is widely studied. The terahertz radiation from ultra- intense laser pulse driven wire target is studied by using the radiation theory of antenna proposed by Smith. The expressions of the radiation field are obtained and the space radiation field and frequency spectrum are presented. Based on the study of the influence of the ratio of laser duration to target length on radiation field distribution, the optimum laser duration for a constant target length is discussed, and the modulation of the target length on the radiation field for a constant laser condition is obtained. Theoretical analysis indicates that the range of frequency is determined by the laser duration, and the distribution of spectrum is determined by the ratio of laser duration to target length, which provides theoretical basement for the experiment design..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 314003 (2015)
Estimating Method of Jamming Thresholds for Laser Irradiated Interline Transfer CCD
Zhang Jianmin, Zhang Zhen, Feng Guobin, Shi Yubin, Cheng Deyan, and Zhao Jun
It is crucial to acquire the jamming thresholds of the photoelectric devices in charge coupled device (CCD) image sensing applications by nonexperimental means, which is a unique way to obtain the thresholds sometimes. Affecting factors of pixel saturation and crosstalk effects in interline transfer CCD are analyzed brIt is crucial to acquire the jamming thresholds of the photoelectric devices in charge coupled device (CCD) image sensing applications by nonexperimental means, which is a unique way to obtain the thresholds sometimes. Affecting factors of pixel saturation and crosstalk effects in interline transfer CCD are analyzed briefly. The intrinsic relationship and difference between vertical smear, blooming and crosstalk are studied. Results preliminarily suggest that crosstalk is not sensitive to the fractional amount of smear. An extrapolation method to estimate thresholds of the pixel saturation and crosstalk column saturation effects with image sensor specification and historical data of laser irradiation effects is proposed. Device parameters such as quantity of saturation signal charge, pixel size, quantum efficiency and blooming suppression are used in the estimation. Laser irradiating experiments are carried out to measure the jamming thresholds of two similar Kodak area CCDs. The deviations between the estimation results and the experimental data are 3% and 2%, respectively. The acceptable deviations indicate that the predicting method is feasible..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 314004 (2015)
Machine Vision
Fast Circle Detector Based on Region-Growing of Gradient and Histogram of Euclidean Distance
Cai Jia, Huang Panfeng, and Zhang Bin
The most existing circle detectors based on Hough transform need to tune many parameters while the methods based on histogram are complex in computation and resource, thus a fast circle detector based on regiongrowing of gradient and histogram of Euclidean distance is presented to solve the above problems. The pixels′ The most existing circle detectors based on Hough transform need to tune many parameters while the methods based on histogram are complex in computation and resource, thus a fast circle detector based on regiongrowing of gradient and histogram of Euclidean distance is presented to solve the above problems. The pixels′ gradient module and direction are computed in the first step and region-growing method is implemented to generate arc support regions. Three coordinates of each arc support region (ASR) are then selected to solve the center and radius of its corresponding circle and determine a square fitting area (SFA). Afterward, the Euclidean distances between every coordinates on each ASR and each coordinate of its ASR’s corresponding SFA are computed and recorded in a three dimensional accumulator. A histogram is used to count the frequency of the distances that participate in the accumulator and the parameters of each circle are acquired. A verification strategy of circular integrity is used to test the detection results. Compared with the histogram based circle detection (HBCD) and random Hough transform (RHT), experimental results indicate that the proposed algorithm is able to detect partial circles, multiple centers or circles in partial occlusion. This method has features of high speed, low consumption, wide range of application and strong anti-interference performance．.
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 315001 (2015)
Online Mixture of Random Naive Bayes Tracker Combined Texture with Shape Feature
Guo Pengyu, Su Ang, Zhang Hongliang, Zhang Xiaohu, and Yu Qifeng
Based on the idea of machine learning and the sufficient appearance, a mixture random Naive Bayes visual tracker with online texture and shape feature selection is proposed. The texture and shape of global and local region is described with binary feature of intensity and pyramid histogram of oriented gradients using nBased on the idea of machine learning and the sufficient appearance, a mixture random Naive Bayes visual tracker with online texture and shape feature selection is proposed. The texture and shape of global and local region is described with binary feature of intensity and pyramid histogram of oriented gradients using normalized spatial pyramid. An online mixture of Naive Bayes classifier is designed and realized according to binary and multimodel description. The classifier predicts the class posterior probability to generate the confidence map, then the tracker analyzes the confidence map to track the object, learns the appearance with maximum likelihood estimation, and selects the feature with cross validation. Compared with homogeneous methods, the tracker is evaluated with performance and complexity based on benchmarks. The experimental results show that the tracker has certain adaption to illumination change and partial occlusion, and fast execution speed as well as little memory space..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 315002 (2015)
Materials
Negative Goos-Hanchen Shift of Left-Handed-Metamaterials Based on the Silver Dendritic Structure
Fang Zhenhua, Luo Chunrong, and Zhao Xiaopeng
To date the experimental reports on Goos-Hanchen (GH) shift of left-handed metamaterials (LHMs) have not been reported since it is theoretically demonstrated. The GH shift of LHMs based on the silver dendritic structure via interferometry is experimentally mecisuked. Wollaston prism is utilized to divide the incident lTo date the experimental reports on Goos-Hanchen (GH) shift of left-handed metamaterials (LHMs) have not been reported since it is theoretically demonstrated. The GH shift of LHMs based on the silver dendritic structure via interferometry is experimentally mecisuked. Wollaston prism is utilized to divide the incident light into s polarized and p polarized light. Then the two polarized light beams are made to interfere with each other to obtain the interference pattern after being reflected from the surface of the sample. And the value of GH shift is obtained by analyzing and calculating the interference pattern. Experimental results confirm that GH shift is negative as the frequency of incident light is consistent with the resonant frequency of silver dendritic LHMs..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 316001 (2015)
Medical Optics and Biotechnology
A Method of Improving Signal-to-Noise Ratio in Spectrally Encoded Microscopy
Liao Jiuling, and Gao Wanrong
Spectrally encoded microscopy is a new reflecting microscopic imaging technique in which a diffraction grating is used to illuminate different positions on the sample with different wavelengths. A spectrally encoded microscopic imaging system is built, and it is based on a swept source at a sweeping rate of 50 kHz. In Spectrally encoded microscopy is a new reflecting microscopic imaging technique in which a diffraction grating is used to illuminate different positions on the sample with different wavelengths. A spectrally encoded microscopic imaging system is built, and it is based on a swept source at a sweeping rate of 50 kHz. In order to detect the weak light backscattered from the sample without a post-amplifier used, balanced detection is employed. The lateral resolution of the device is improved from 13.93 mm to 5.52 mm by imaging a USAF-1951 resolution target. The images of onion cells show that the signal-to-noise ratio (SNR) increases from 15.07 dB to 22.6 dB by balanced detection, demonstrating the capability of the method to improve both of the lateral resolution and SNR of the system. Images of in vitro swine gastric pits are presented to demonstrate tissue imaging capability of the technique. The work is useful for developing corresponding devices for potential clinical applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 317001 (2015)
Nonlinear Optics
Investigation of Stimulated Raman Scattering Characteristics in D2, H2 and D2/H2 Mixtures
Cao Kaifa, Huang Jian, and Hu Shunxing
The stimulated Raman scattering (SRS) is an important method to extend the laser wavelength range. Nonlinear optical processes in gas have complex impacts on SRS laser, so it is important to make an experimental study on the relationship between the characteristic of SRS laser and gas pressure and focal length of lens The stimulated Raman scattering (SRS) is an important method to extend the laser wavelength range. Nonlinear optical processes in gas have complex impacts on SRS laser, so it is important to make an experimental study on the relationship between the characteristic of SRS laser and gas pressure and focal length of lens for applications of SRS laser. The SRS experimental device and measurement system are introduced. Its pump source is a pulsed Nd:YAG laser at 266 nm, and active gases (H2 and D2, H2/D2 mixtures) are sealed in the 100 cm long Raman cell. The outgoing SRS laser split by a prism is measured by an energy meter for the study of SRS characteristics of the active gases. The relationship between the energy of outgoing Stokes and anti- Stokes SRS laser in the H2, D2 and H2/D2 mixtures and gas pressure and focal length of lens is presented. The laser of 12 wavelength bands from 217.84 nm to 447.15 nm are obtained, which effectively expand the scope of the application of Raman laser. The research results have very important practical application value for the use of gas SRS laser..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 319001 (2015)
Theoretical Analysis and Experiment of Monolayer Chirality at Air/Water Interface by in Situ Surface Second Harmonic Generation Linear Dichroism
Wang Xiaoyu, Li Lin, Lin Lu, Zhang Zhen, Lu Zhou, and Guo Yuan
Second harmonic generation (SHG)- linear dichroism (SHG- LD) is an important method for the investigation of monolayer chirality at air/water interface. The chirality SHG response may originate from the contributions of electric dipole transitions or from contributions of both electric dipole transitions and magnetic dSecond harmonic generation (SHG)- linear dichroism (SHG- LD) is an important method for the investigation of monolayer chirality at air/water interface. The chirality SHG response may originate from the contributions of electric dipole transitions or from contributions of both electric dipole transitions and magnetic dipole transitions. The distinction between these two cases is a prerequisite when studying the formation mechanism of the interfacial supramolecular chiraliy. The numerical simulations of the S-polarized SHG intensity as a function of the incident polarization angle are presented and compared for the two cases. The influences on the chirality SHG responses from the second-order nonlinear susceptibility tensors which account for the contributions of electric dipole transitions and magnetic dipole transitions are also analyzed, respectively. In addition, the significance of theoretical simulations to the analysis of experimental data is verified by the SHG- LD experiments on the supramolecular chirality of the porphyrin molecules at air/water interface..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 319002 (2015)
Study on Uniqueness of Experimental Expansion Coefficients for D-p-A Structured Organic Optical Materials
Wang Fuxiang, Han Wenwei, Yang Xuwen, Liu Zhengwei, and Pan Qinhe
Based on single-beam polarization second-harmonic generation, when polarizations of both initial input beam and second- harmonic output beam are linearly polarized in chiral experimental setup, uniqueness of nonzero experimental fitting expansion coefficients f，g and h related to p + s- polarized second- harmonic signaBased on single-beam polarization second-harmonic generation, when polarizations of both initial input beam and second- harmonic output beam are linearly polarized in chiral experimental setup, uniqueness of nonzero experimental fitting expansion coefficients f，g and h related to p + s- polarized second- harmonic signal is reported. The results indicate that for organic optical molecules with D- p- A structured, these experimental expansion coefficients are unique for s- and p±s-polarized initial beams, but they are not unique for p- polarized initial beam, and the simulated results of the p + s- polarized second- harmonic signal can completely explain the contradiction between theory and experiment. To precisely characterize all the secondorder nonlinear susceptibility tensor components of the D- p- A structured materials, it is necessary to avoid using the p-polarized initial beam in a chiral experimental setup..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 319003 (2015)
Investigation on High-Bit All Optical Quantization Based on Soliton Self-Frequency Shift Effect
Wu Kan, Chen Ying, Chen Xiangning, and Chen Jianping
The high-precision all optical quantization technology based on soliton self-frequency shift (SSFS) effect is investigated. It is still unclear whether this technology is able to achieve high-precision quantization although some experimental results have been reported. Investigating the properties of SSFS effect by simThe high-precision all optical quantization technology based on soliton self-frequency shift (SSFS) effect is investigated. It is still unclear whether this technology is able to achieve high-precision quantization although some experimental results have been reported. Investigating the properties of SSFS effect by simulation, it is found that for a soliton pulse with optimal t=150 fs, the number of bits (NOB) can be up to 8 with the effective number of bits (ENOB) equal to 7.02. Narrower pulse width cannot obtain the same NOB whereas wider pulse width affects the linearity of the quantization function and reduces the ENOB. A pulse width of 150 fs requires a bandwidth of 9.8 nm and an average power of 0.92 W under 50 GHz sampling pulse rate, which is within the capability of current optical technologies. Chirp broadens the pulse width and reduces the NOB and ENOB significantly and thus should be avoided..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 319004 (2015)
Numerical Study on Scattering Properties for the Stimulated Brillouin Scattering Fiber
Zhang Cong, Yu Wenfeng, Li Zhenglin, and Lu Ying
Through the approximate three- wave- coupling equations, based on Langevin noise model of the stimulated Brillouin scattering, the stimulated Brillouin scattering process in optical fiber is numerically simulated using the finite difference time domain method. As for the single-mode fiber of 10 km long and with the refThrough the approximate three- wave- coupling equations, based on Langevin noise model of the stimulated Brillouin scattering, the stimulated Brillouin scattering process in optical fiber is numerically simulated using the finite difference time domain method. As for the single-mode fiber of 10 km long and with the refractive index of 1.5132, the characteristics of the optical field and the acoustic field of the temporal and spatial variation and the power variation of scattering light within 50 ms are analyzed. In the numerical simulation, under the function of pump beam and with Stokes light as the incident vibration light into the other end of the optical fiber, it is found that whether the polarized light exists or not will affect the amplitude of the temporal and spatial variation of the pump light, scattering light field and acoustic field, and it is obtained that the scattering light power tends toward saturation with time when the Stokes light exists and the scattering light power shows nearly linear variation with time when no Stokes light exists..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 319005 (2015)
Measurement of Dilute Solute Nonlinearities from Solution by Using Dual-Arm Phase Object Z-scan Technique
Shi Shengtao, Yang Junyi, Lu Xun, Wang Qi, Liu Chengyuan, Luo Xiaoqin, and Song Yinglin
A dual-arm phase object (PO) Z-scan technique is proposed based on PO Z-scan technique, in which an identical optical path is added into the PO Z-scan setup. Compared with the conventional Z-scan technique, PO Z-scan technique can distinguish the third-order nonlinear refraction from the transient thermally induced nonA dual-arm phase object (PO) Z-scan technique is proposed based on PO Z-scan technique, in which an identical optical path is added into the PO Z-scan setup. Compared with the conventional Z-scan technique, PO Z-scan technique can distinguish the third-order nonlinear refraction from the transient thermally induced nonlinearity and realize the single pulse measurement, and the system sensitivity is greater than Z-scan technique. However, previous methods cannot extract the dilute solute nonlinearities from solution well, the dual-arm PO Zscan technique can greatly improve the measurement signal-to-noise ratio, and the dilute solute nonlinearities from solution can be measured accurately..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 319006 (2015)
Optical Design and Fabrication
Improvement of the Diamond Turned Surface Texture by Bonnet Polishing Process
Wang Peng, Suet To, and Hui Changshun
Single point diamond turing (SPDT) technique is widely employed in ultra-precision machining of optics. However, the inherent tool marks with strong periodicity induce scattering effects of turned surfaces, significantly deteriorating the optical performances. To suppress the scattering and accordingly achieve optical Single point diamond turing (SPDT) technique is widely employed in ultra-precision machining of optics. However, the inherent tool marks with strong periodicity induce scattering effects of turned surfaces, significantly deteriorating the optical performances. To suppress the scattering and accordingly achieve optical surface with high quality, the bonnet polishing method is adopted herein to actively modify structures of the residual tool marks. Taking advantage of the Taguchi experiments where the roughness and the power spectral density (PSD) of the polished surface are served as the improving criteria, the optimal polishing parameters are obtained. Polishing experiment is conducted on a fine turned surface by adopting the optimal parameters. The results indicate that the roughness Ra reduces from 3.81 nm to 1.42 nm and the PSDs of surface errors in all the spatial frequencies are also significantly reduced. In addition, the inherent scattering fringes of the original surface are well eliminated, demonstrating the efficiency of the polishing method as well as the optimization method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 322001 (2015)
Analysis and Design of Unobscured Flat-Field Two-Mirror Telescopic Objective with Wide Field of View and Large Relative Aperture
Zhou Zhengping, Zhao Zhicheng, Jin Yangming, and Shen Weimin
According to the performance and application of the hyperspectral imager with wide field of view and large relative aperture, a simple two-mirror fore objective with biased field of view consisting of one convex and one concave mirror is studied and designed. Based on its Gaussian optics and astigmatism analysis with YAccording to the performance and application of the hyperspectral imager with wide field of view and large relative aperture, a simple two-mirror fore objective with biased field of view consisting of one convex and one concave mirror is studied and designed. Based on its Gaussian optics and astigmatism analysis with Young′ s formulas and under the normalization condition with respect to the optical system′s focal length，the vertex curvature radius of the convex mirror should be chosen within the interval of [2.5 mm, 3.24 mm). The approach to determine its initial structural parameters which meet with expected performance and the corresponding results are presented. As an example, a fore two-mirror imagery telecentric objective with biased field of view for nonobscuration is optimally designed. Its working wavelength ranges from 0.4 to 1.0 mm, and its relative aperture and its linear field of view is respectively up to 1/1.8 and 40°. Both of mirrors are oblate ellipsoid surface with only conic coefficient. The designed lens has many advantages of simple and compact construction，near diffraction-limited imaging quality，imagery telecentricity, high speed and collection power，and wide and flat field of view. It will become the ideal fore objective of imaging spectrometers with high and spectral resolution and high signal-to-noise..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 322002 (2015)
Optimized Design of Infrared Opto-Mechanical Systems Based on the Spontaneous Emission Suppression
Zhou Jun, Li Juan, Wang Qingfeng, Xu Minda, and Zhang Congyue
For the low background detecting infrared opto-mechanical systems, the signal is very weak and the spontaneous emission of the system has a large impact. This paper discusses the optimized design of infrared opto-mechanical systems based on the spontaneous emission suppression. The refraction-reflection system, coaxialFor the low background detecting infrared opto-mechanical systems, the signal is very weak and the spontaneous emission of the system has a large impact. This paper discusses the optimized design of infrared opto-mechanical systems based on the spontaneous emission suppression. The refraction-reflection system, coaxial reflection system and off-axis reflection system are compared on the spontaneous emission suppression in the way of effective emissivity and equivalent blackbody radiation temperature(EBRT). We find that the reflection system is better than refraction-reflection system and the off-axis reflection system is the best. From the change of equivalent blackbody radiation temperature, the paper introduces choosing the wavelength range, the optimized design of opto-mechanical structure and the surface processing. It is concluded that the even longer wavelength detecting has clearly advantage in the low background and it is better that the reflective surfaces and black surfaces has reasonable layout. The impact of refrigeration to the opto-mechanical systems suppressing the spontaneous emission is discussed. We find that refrigeration system can suppress spontaneous emission obviously, while the efficiency is worse when the refrigeration temperature is lower. So the crucial surfaces refrigeration can be adopted..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 322003 (2015)
Experimental Study of Wavefront Sensorless Adaptive Optics Based on Deformable Mirror Eigen Modes
Yu Ji, and Dong Bing
The wavefront correction methods in wavefront sensorless adaptive optics can be classified into two groups: model-free optimization algorithms and modal-based optimization algorithms. In this paper, the feasibility of optimization algorithm based on deformable mirror (DM) eigen modes is verified by the experiments. ExpThe wavefront correction methods in wavefront sensorless adaptive optics can be classified into two groups: model-free optimization algorithms and modal-based optimization algorithms. In this paper, the feasibility of optimization algorithm based on deformable mirror (DM) eigen modes is verified by the experiments. Experimental results show that the correction accuracy of algorithm using DM eigen modes is higher than that of using Lukosz modes because the mode fitting error can be avoided. Since the correction amount of each DM eigen mode can be estimated independently, a proper mode number is chosen according to the spatial frequency contents in initial wavefront aberration to improve the correction speed. Compared with the commonly used stochastic parallel gradient descent (SPGD) algorithm, the correction accuracy of modal-based algorithm is nearly the same as it, but the correction speed is improved by one order of magnitude..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 322004 (2015)
Optical Design of High-Efficiency Ripple Plate Illuminator for EUV Lithography
Liang Xinli, Li Yanqiu, and Mei Qiuli
A high- efficiency ripple plate illumination system for extreme ultraviolet (EUV) lithography is proposed. A cylindrical mirrors array is used as ripple plate mirror to simplify the system. By analyzing the characteristics of reflection on ripple plate, we design a relay system with a modified compound parabolic concenA high- efficiency ripple plate illumination system for extreme ultraviolet (EUV) lithography is proposed. A cylindrical mirrors array is used as ripple plate mirror to simplify the system. By analyzing the characteristics of reflection on ripple plate, we design a relay system with a modified compound parabolic concentrator and two conic mirrors to reduce the efficiency loss caused by excessive number of reflective mirrors. Compared with the traditional EUV lithography illumination system, it greatly improves the system′ s efficiency. A design example for a numerical aperture (NA) 0.33 projection objective is given and the efficiency of the illuminator is 39.7% while the slit non- uniformity of the scanning energy distribution is 2.7% in a prescribed arc area, which proves the feasibility of the design..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 322005 (2015)
Optimized Design and Research of Secondary Optics in Concentrating Photovoltaic Module
Yang Guanghui, Liu Youqiang, Yao Shun, Guo Limin, Chen Bingzhen, and Wang Zhiyong
In concentrating photovoltaic module, employment of secondary optics can be effective in increasing the acceptance angle and incident light, as well as improving the energy uniformity of focal spot. A design of reflective secondary optics for concentrating photovoltaic module is presented. The 3D model of this design iIn concentrating photovoltaic module, employment of secondary optics can be effective in increasing the acceptance angle and incident light, as well as improving the energy uniformity of focal spot. A design of reflective secondary optics for concentrating photovoltaic module is presented. The 3D model of this design is established by Solidworks software and important parameters such as inclination angle and component height get optimized using Zemax software. According to the design and simulation results, several secondary glass prisms with different parameters are fabricated and tested in combination with Fresnel lens and multi-junction solar cell. The sun-simulator I-V test results show that the combination has the highest output power when secondary optics height is 6mm and upper circle diameter is 7 mm. The output power can reach 720 mW, which improves 16% compare to without secondary optics. It shows that secondary optics is very important in concentrating photovoltaic module..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 322006 (2015)
Manufacture of Silicon Modification Layer on Silicon Carbide Surface by Magnetorheological Finishing
Bai Yang, Zhang Feng, Li Longxiang, Zheng Ligong, and Zhang Xuejun
Magnetorheological finishing (MRF) process is adopted to overcome the drawback of traditional polishing method in final finishing of SiC after silicon modified and removing the debris of optical surface in final finishing with high efficiency and fast convergence. The requirements of magnetorheological (MR) polishing fMagnetorheological finishing (MRF) process is adopted to overcome the drawback of traditional polishing method in final finishing of SiC after silicon modified and removing the debris of optical surface in final finishing with high efficiency and fast convergence. The requirements of magnetorheological (MR) polishing fluid are proposed according to the actual polishing situation. The rheological characteristic and dispersion stability are tested, which verify that the prepared MR polishing fluid possesses good performance. A silicon modified reactbonded coaxial asphere mirror with diameter of 130 mm (effective sub-aperture is 120 mm) is polished with two iteration in three hours approximately. The root-mean-square (RMS) of the surface accuracy is improved from 0.051λ (λ=632.8 nm) to 0.012λ rapidly and the surface roughness Ra reaches 0.618 nm. The results proves that the prepared MR polishing fluid can satisfy the polishing requirement of modification layer on silicon carbide and MRF possesses outstanding advantages in final finishing of silicon modified mirror..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 322007 (2015)
Optical Devices
Retroreflective Performance Analysis of Cube Corner Membrane Structure
Luo Han, and Yuan Changying
Compared with the traditional glass beads embedded type membrane structure, cube corner type membrane structure has higher efficiency of retroreflection, it is the foundation of designing and producing diamond grade reflective film. In order to meet different application requirements, we need to apply some change on thCompared with the traditional glass beads embedded type membrane structure, cube corner type membrane structure has higher efficiency of retroreflection, it is the foundation of designing and producing diamond grade reflective film. In order to meet different application requirements, we need to apply some change on the structure of the basic cube corner array, so as to increase the effective incident angle range, and to reduce anisotropy of retroreflection coefficient. Establishing the connection of membrane structure and the performance of the retroreflection is of great significance to improve the structure design of retroreflection material, which shortens the design and exploitation process. A program is written in order to calculate the retroreflectance of cube corner retroreflective sheeting. This program is based on ray tracing technology, primary light loss in the process of transmission(effective projection section, reflection and refraction loss)as well as the polarization effect is taken into account in this program. The retroreflection performance of several types of cube corner structures are anlalyzed by using the program, thus the reliability of the program is examined. It is also proved that the application of this program in the simulation can greatly improve the accuracy and efficiency than usual result..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 323001 (2015)
Study on the Heat Sink Structure and Heat Transfer Effect of Liquid Cooling System for High Power LEDs
Tian Lixin, Wen Shangsheng, Huang Weiming, Xia Yunyun, and Yao Rihui
To design the heat sink of liquid cooling system effectively and improve the comprehensive performance of heat transfer for high power LEDs, the LED maximum temperature and thermal resistance of three types of heat sinks are numerically investigated. The mechanism of heat transfer is analyzed by using the field synergyTo design the heat sink of liquid cooling system effectively and improve the comprehensive performance of heat transfer for high power LEDs, the LED maximum temperature and thermal resistance of three types of heat sinks are numerically investigated. The mechanism of heat transfer is analyzed by using the field synergy principle, and the variation of the Nusselt number and friction factor are examined with Reynolds number. And using the thermal enhancement factor to express the comprehensive performance of heat transfer between the heat transfer performance and flow resistance. The results show that the LED maximum temperature and thermal resistance using the rectangular fin with the inclined angle of 30° is lowest, the heat transfer enhancement is highest, and rhombic fin is followed, vertical parallel fin is worst. The rectangular fin with the inclined angle of 30° and rhombic fin have the higher flow resistance when they have the higher heat transfer performance, because of the oblique angle. Considering the heat transfer performance and flow resistance, rhombic fin has the highest comprehensive performance of heat transfer..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 323003 (2015)
Quantum Optics
Teleportation for Atomic State Based on Disentanglement-Free State
Wang Zhongjie, Ruan Fei, and Fang Xu
Quantum teleportation is easily effected by noisy environment. In order to decrease this adverse effect induced by the amplitude- damping noisy environment, a scheme for quantum teleportation is proposed based on disentanglement- free state and quantum error- avoiding codes. In this scheme, a kind of disentanglement- fQuantum teleportation is easily effected by noisy environment. In order to decrease this adverse effect induced by the amplitude- damping noisy environment, a scheme for quantum teleportation is proposed based on disentanglement- free state and quantum error- avoiding codes. In this scheme, a kind of disentanglement- free four- qubit state is used as the quantum entanglement channel, and single qubit of the teleportated quantum information is encoded into two qubits. This scheme has the advantages that quantum teleportation has full fidelity and the success probability for this teleportation scheme is 100% . The study has important applications in improvement of quantum communication..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 327001 (2015)
Remote Sensing and Sensors
Study on Inverting Soil Moisture Content Based on the Field Bidirectional Reflectance Information with the Reflection Model
Lü Yunfeng, Sun Zhongqiu, and Zhao Yunsheng
In order to invert the soil moisture content and analyze the influence of soil moisture content on the bidirectional reflectance, the parameters of bidirectional reflectance model are obtained based on the multi-angle hyper spectral data in the field, and the soil moisture content using the calculated values is inverteIn order to invert the soil moisture content and analyze the influence of soil moisture content on the bidirectional reflectance, the parameters of bidirectional reflectance model are obtained based on the multi-angle hyper spectral data in the field, and the soil moisture content using the calculated values is inverted. The relationship between model parameters in three wavelengths and different directions and moisture content is analized, the differences of inverting soil moisture content results based on model in different directions are found, and the inverting accuracy is stablest at 865 nm. The result suggests that based on the bidirectional reflectance distribution characteristics, the soil moisture content can be inverted with high accuracy. At the same time, the effect of the directional reflectance on the inversion accuracy should also be considered..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 328001 (2015)
MTF Computing Method of Remote Sensing Image after Removing the Effects of Atmospheric Adjacency Effect
Li Haiwei, Zhang Hao, Chen Zhengchao, and Yuan Juan
Taking into account the effect of remote sensing images blurred by the atmospheric, the effect of atmospheric modulation transfer function (MTF) is removed by correcting the adjacent effects in atmospheric correction on the basis of traditional knife- edge method, and the MTF is calculated on a real surface reflectanceTaking into account the effect of remote sensing images blurred by the atmospheric, the effect of atmospheric modulation transfer function (MTF) is removed by correcting the adjacent effects in atmospheric correction on the basis of traditional knife- edge method, and the MTF is calculated on a real surface reflectance images. The result which objectively reflects the MTF of the sensor is better than conventional methods and is closer to the laboratory measurements. In addition, the effects of the aerosol optical thickness on the MTF measurement through the simulation experiments are analyzed, the experimental results show that the proposed method is more suitable for on-orbit MTF measurement than the traditional knife-edge method, and more objectively reflect the real imaging sensor..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 328002 (2015)
Investigation on Image Formation of Wide Swath Synthetic Aperture Ladar Using Non-Symmetric Beam-Pattern Illumination
Wu Jin, Zhao Zhilong, Duan Hongcheng, Wu Shudong, and Huang Wenwu
Synthetic aperture ladar (SAL) can achieve long distance objects high resolutions imaging. However, the mapping bandwidth is generally small, which probably limits its applications in land surveillance. In order to solve the problem, practical imaging range of a wide swath SAL is suggested and a wide swath SAL using noSynthetic aperture ladar (SAL) can achieve long distance objects high resolutions imaging. However, the mapping bandwidth is generally small, which probably limits its applications in land surveillance. In order to solve the problem, practical imaging range of a wide swath SAL is suggested and a wide swath SAL using non-symmetric beam-pattern illumination with short azimuth size and long range size is investigated in detail. By wave optics diffraction theory, detailed theoretical descriptions of the image formation theory on the wide swath SAL as well as the mathematical simulations are given. The results show that due to the characteristic of short optical wavelength, the conventional image formation theory used in SAL data processing is approximately applied in wide swath SAL using non- symmetric beam- pattern illumination, that is, range compression by Fourier transformation and azimuth image focusing by matched filtering..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 328003 (2015)
Raman Lidar for Atmospheric Temperature, Humidity and Aerosols up to Troposphere Height
Wang Yufeng, Gao Fei, Zhu Chengxuan, He Tingyao, and Hua Dengxin
In order to achieve measurement of atmospheric temperature, water vapor (relative humidity) and aerosol simultaneously, a Raman lidar system has been developed, and a high-performance spectroscopic box composed of dichroic mirrors and narrow-band interference filters is used to separate the different-wavelength lidar rIn order to achieve measurement of atmospheric temperature, water vapor (relative humidity) and aerosol simultaneously, a Raman lidar system has been developed, and a high-performance spectroscopic box composed of dichroic mirrors and narrow-band interference filters is used to separate the different-wavelength lidar return signal and to extract the interested return signal with high efficiency. The method is proposed for profiling the atmospheric water vapor density, temperature and aerosol extinction coefficient, and thus the profile of relative humidity is obtained. Preliminary experiments are carried out for simultaneous atmospheric parameter detection in Xi′an under clear and cloudy conditions, the vertical profiles of water vapor density, temperature, relative humidity and aerosol extinction coefficient are analyzed, and the variation in water vapor in the clouds and the inversion layer is obtained. The observed results show that under the conditions of integration time of 15 min and laser energy of 150 mJ, the effective simultaneous detection range for temperature and relative humidity achieves up to 16 km under clear condition, the temperature inversion layer is obtained in the lower atmospheric layer and at the top of the cloud layer, and synchronization increasing trend is found between water vapor density and relative humidity within the high cloud layer and water vapor layer. The obtained results are better consistent with radiosonde data in terms of the water vapor density, temperature and relative humidity profiles, which verifies the reliability of the Raman lidar to achieve real-time multi-parameter measurement up to troposphere height, and long-term observation and studies can be conducted to provide reliable data for research of climate change and haze process..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 328004 (2015)
Effect of Thermal Stress and Residual Gas Pressure on the Thermal Response of Optical Fiber Fabry-Perot Pressure Sensor
Wu Zhenhai, Liu Tiegen, Jiang Junfeng, Liu Kun, Wang Shuang, Yin Jinde, Zou Shengliang, Qin Zunqi, and Wu Fan
A new model for optical fiber Fabry-Perot (F-P) pressure sensor with thermal stress and residual gas pressure is presented, then their impacts on thermal response of the F-P sensor are analyzed. It shows that the linear relationship between the change of cavity length and temperature has changed when thermal stress andA new model for optical fiber Fabry-Perot (F-P) pressure sensor with thermal stress and residual gas pressure is presented, then their impacts on thermal response of the F-P sensor are analyzed. It shows that the linear relationship between the change of cavity length and temperature has changed when thermal stress and residual gas pressure are considered. In the condition that the applying outer pressure is 100 kPa, the thermal stress plays a major influence on the sensor when the initial residual gas pressure is less than 0.87 kPa, otherwise the residual gas pressure plays the major influence on the sensor. Three kinds of optical fiber F-P sensors with different residual gas pressures are produced, then the experimental system in the temperature range from -20 ℃ to 70 ℃ is built. The result shows that the cavity length and the thermal sensitivity varying with the temperature from the experimental data agrees well with the theoretical analysis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 328005 (2015)
Reviews
Measurement of Flexoelectric Coefficient Based on the Dynamic Response of Liquid Crystal
Xing Hongyu, Ye Wenjiang, Cai Minglei, Liu Xiaomeng, Zhang Zhidong, and Xuan Li
Based on the self-assembly experimental installation, the influence of flexoelectric effect on the dynamic response of strong anchoring hybrid aligned nematic (HAN) liquid crystal is studied. The positive and negative monopulse with pulse width of 250 ms and adjustable amplitude are applied to HAN cell during experimenBased on the self-assembly experimental installation, the influence of flexoelectric effect on the dynamic response of strong anchoring hybrid aligned nematic (HAN) liquid crystal is studied. The positive and negative monopulse with pulse width of 250 ms and adjustable amplitude are applied to HAN cell during experiment. The results show that the dynamic response of liquid crystal is different from the pulse with the same amplitude, as well as from the positive pulse or negative pulse with different amplitudes. Through comparing the experimental curves of the dynamic response of liquid crystal for different positive pulses 3 V, 4 V, 5 V, 6 V with the corresponding theoretical curves with the flexoelectric effect considered, the sum of flexoelectric coefficient of liquid crystal material E7 is e11+e33=4.0×10-11 C/m, which is in agreement with the experimental measurement value reported in the literature..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 323002 (2015)
Spectroscopy
Research on Volatiles of Bulbus Allii Macrostemonis from Different Areas and Different Original Plants Based on Headspace and SERS
Zhang Chuanyun, Si Minzhen, Li Lun, and Zhang Deqing
The volatiles of Bulbus Allii Macrostemonis from different areas and different original plants have been studied by headspace combined with surface- enhanced Raman scattering (SERS) using nano- silver colloid as substrate. Volatile SERS spectra of Allium macrostemon Bunge from four different areas and Allium chinense fThe volatiles of Bulbus Allii Macrostemonis from different areas and different original plants have been studied by headspace combined with surface- enhanced Raman scattering (SERS) using nano- silver colloid as substrate. Volatile SERS spectra of Allium macrostemon Bunge from four different areas and Allium chinense from Chuxiong are very similar and well repeated. The peaks at 375, 635, 673, 712, 781, 893, 1025, 1086, 1222, 1322, 1629 cm-1 in their volatile SERS spectra match well with each other. The volatile SERS spectra are compared respectively with the volatile SERS spectra of liquid allyl methyl sulfide, 1- propanethiol and their mixture. The results show that the volatile SERS spectra of Allium macrostemon Bunge and Allium chinense are basically consistent with that of the mixture of liquid allyl methyl sulfide and 1- propanethiol. It illustrates that volatiles of Allium macrostemon Bunge from different areas and Allium chinense from Chuxiong contain allyl methyl sulfide and 1- propanethiol. All results have revealed that the headspace combining with SERS technology can be directly used to study volatiles of Bulbus Allii Macrostemonis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 330001 (2015)
Study on Quantitative Analysis of SDBS and Betaine Complex System in Polluted Water by Excited Spectroscopy
Shi Dongpo, Yin Xianqing, Zheng Yancheng, Chen Wu, Fu Jiaxin, and Ren Zhaohua
It is hard to determine the concentration of sodium lauryl benzenesulfate (SDBS) or betaine in their complex system due to the strong interference between SDBS and betaine. A new method is developed for reducing the interactions between SDBS and betaine by adding β-cyclodextrin (β-CD) in their aqueous complex solution.It is hard to determine the concentration of sodium lauryl benzenesulfate (SDBS) or betaine in their complex system due to the strong interference between SDBS and betaine. A new method is developed for reducing the interactions between SDBS and betaine by adding β-cyclodextrin (β-CD) in their aqueous complex solution. Several factors such as the effect of β-CD on quantitative analysis of SDBS, the anti-interference ability of β-CD as well as the effect of interactions between SDBS and betaine are investigated. The results indicate that the effect of the interactions between SDBS and betaine on determination of SDBS/betaine complex system can be greatly reduced by adding β-CD, thus, the determination precision of SDBS and betaine can be greatly improved. The recovery rates of SDBS and betaine are respectively reduced from 103.9%~105.9% and 103.4%~174.9% to 101.8%~ 102.3% and 102.3%~102.8% in their aqueous complex solution. Besides, the experimental results further show that the SDBS and betaine complex in environmental water can also be analyzed by the method. The results of nuclear magnetic resonance hydrogen spectrum (1H-NMR) analysis and Fourier transform infrared spectroscopy (FT-IR) analysis show that the stale β-CD—SDBS inclusion can be formed by entering of SDBS molecules from the narrow or broad mouth of β-CD. The interference between SDBS and betaine can be reduced by β-CD because of the formation of β-CD and SDBS inclusion complex..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 330002 (2015)
Thin Films
Preparation and Characteristic of Oxide Capping-Layer on Extreme Ultraviolet Reflective Mirrors
Wang Xun, Jin Chunshui, Li Chun, and Kuang Shangqi
The development of industrial applications of extreme ultraviolet lithography (EUVL) severely based on surface oxidation and carbon contamination on using extreme ultraviolet (EUV) reflective mirrors. The capping layer coating on the Mo/Si multilayer is a promising method to improve the stability and service life of thThe development of industrial applications of extreme ultraviolet lithography (EUVL) severely based on surface oxidation and carbon contamination on using extreme ultraviolet (EUV) reflective mirrors. The capping layer coating on the Mo/Si multilayer is a promising method to improve the stability and service life of the reflective mirrors. The capping layer is prepared by direct current reactive magnetron sputtering. The "hysteresis loop”of oxygen flow and sputtering voltage is established, the required oxygen flow for different oxides is accurately grasped. Choosing the RuO2 and TiO2 as the capping layer materials; the different film characteristics in each state is analyzed. For TiO2 films, crystal phase, surface roughness, cross section uniformity and chemical composition are evaluated. 97.2% TiO2 content (mass fraction) of Ti-oxide is obtained; reflectivity of Mo/Si multilayer with 2 nm TiO2 as capping layer is controlled in 5%; surface roughness less than 100 pm, dense and uniform amorphous TiO2 films is fabricated to make this capping layer achieve the basic requirements of EUV..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 35, Issue 3, 331001 (2015)
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