Contents
2012
Volume: 32 Issue 10
47 Article(s)
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Atmospheric Optics and Oceanic Optics
A MODTRAN-Based Double-Lookup-Tables Retrieval Algorithm for Water Vapor Amount of Hyperspectral Data
Tao Dongxing, Zhao Huijie, and Jia Guorui
Assuming that surface reflectance changes linearly with wavelength in the near-infrared band and the impact of path radiance is considered. An algorithm based on radiative transfer model MODTRAN, which gets the column water vapor amount using two lookup-tables (LUTs) is developed. Cubic interpolation method is used to Assuming that surface reflectance changes linearly with wavelength in the near-infrared band and the impact of path radiance is considered. An algorithm based on radiative transfer model MODTRAN, which gets the column water vapor amount using two lookup-tables (LUTs) is developed. Cubic interpolation method is used to reduce the water vapor amount step in LUTs. Using the LUTs through a stepwise-search method, water vapor amount distribution image can be gained from hyperspectral data. It shows that the radiance gotten by cubic spline interpolation only has 0.1% error compared with MODTRAN simulated radiance. Water retrieval is performed to two scenes of airborne visible/infrared imaging spectrometer (AVIRIS) data, and two water vapor amount distribution images are obtained. Reflectance data are obtained using the images through atmosphere correction. Water vapor amount distribution images change smoothly without bright or dark spots in them, and there is no peaks or valleys in the water vapor absorption band of reflectance spectra. It is proved that the algorithm is valid..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1001001 (2012)
Detectors
Study of Unusual Response Mechanism to PV HgCdTe Linear Array Detector by Hard Light
Qiu Weicheng, Wang Rui, Jiang Tian, Xu Zhongjie, and Cheng Xiang′ai
The photovoltaic HgCdTe detectors with capacitive transimpedance amplifiers (CTIA) readout circuit is irradiated by various in-band lasers. All is found that the nonirradiated detection units′ basal signals have responded, when the incident laser power density increases about to 10-2 W/cm2. The responded value initiallThe photovoltaic HgCdTe detectors with capacitive transimpedance amplifiers (CTIA) readout circuit is irradiated by various in-band lasers. All is found that the nonirradiated detection units′ basal signals have responded, when the incident laser power density increases about to 10-2 W/cm2. The responded value initially decreases and then increases, and the noise increases with the power density increasing. With further investigation, it is demonstrated that the paradoxical responded phenomenon is primarily caused by the public P pole structure of linear array detectors and the public Vref voltage structure of circuits..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1004001 (2012)
Influence of Motion Status on Multispectral Optical Characteristics of Satellites
Wang Fugang, Zhang Wei, Wang Hongyuan, and Hou Qingyu
The background characteristics, materials characteristics, structure characteristics and orbit characteristics of the satellite are comprehensively considered to study the influence of motion status of satellite on its multispectral optical characteristics. The motion status of the satellite can be classified into spinThe background characteristics, materials characteristics, structure characteristics and orbit characteristics of the satellite are comprehensively considered to study the influence of motion status of satellite on its multispectral optical characteristics. The motion status of the satellite can be classified into spin-stabilized, three-axis stabilized and “tumbling” status. Based on optical radiation theory, the calculation model of multispectral characteristics of satellites is built for three kinds of motion status combined with the performance parameters of the detector. Taking HY-1 satellite and SJ-2 satellite as examples, the simulation on influence of motion status on multispectral optical characteristics of satellites is made. The results show that satellites with different motion status exhibit remarkable different multispectral characteristics, which provides a certain reference for detection and identification of satellites..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1004002 (2012)
Diffraction and Gratings
Design of Double-Layer Coupling Gratings for Full-Color Helmet Mounted Display
You Meng, Huang Zhanhua, and Cai Huaiyu
In the design of full-color waveguide holographic head-up display, the color is always uneven or the structure is over-complex. A novel double coupling grating structure is designed and optimized with embedded layers of different refractive indexes and thicknesses. Based on rigorous coupled-wave analysis (RCWA), the caIn the design of full-color waveguide holographic head-up display, the color is always uneven or the structure is over-complex. A novel double coupling grating structure is designed and optimized with embedded layers of different refractive indexes and thicknesses. Based on rigorous coupled-wave analysis (RCWA), the calculations show that the structure can achieve a more uniform color imaging in the primary field of view. It′s simplified and reliable for mass production. The double-grating is designed with central wavelength of 470 nm and 632 nm, respectively, to compensate the diffraction energy. After optimization, when the incident angle changes during the range from -11° to 11°, the diffraction efficiency (DE) of the RGB wavelengths is greater than 85% in the primary field of view and the maximum efficiency differs by less than 5%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1005001 (2012)
Fiber Optics and Optical Communications
Low-Loss Splicing Based on the Technique of Mode-Field Matching by Fusion Taper Rig
Yang Qing, Shi Jielong, Sun Weisheng, and Huang Tubin
The low-loss splicing technique between photonic crystal fibers (PCF) and normal single-mode fibers (SMF) is a critical problem that should be solved before the application of PCF. A new method to realize low loss splicing based on the new technique of mode field matching by fusion taper rig is proposed. The preprocessThe low-loss splicing technique between photonic crystal fibers (PCF) and normal single-mode fibers (SMF) is a critical problem that should be solved before the application of PCF. A new method to realize low loss splicing based on the new technique of mode field matching by fusion taper rig is proposed. The preprocessing that changes the mode-field diameter (MFD) is first done by fusion taper rig. Using traditional arc-fusion method combined with fusion taper rig, the experimental study on splicing loss between different PCF and SMF is performed. During the experiment, mode field matching between different PCF and SMF is observed by changing fusion taper rig′s parameters. The splicing loss can drop to below 0.3 dB by optimizing the discharge parameters, and then satisfy the application requirement. In return, the optimal sets of fusion splice parameters are determined and low-loss, high-strength splicing between the PCF and SMF is achieved. This method can provide the reference for other similar splicing between PCF and SMF..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1006001 (2012)
Theoretical and Experimental Investigation of Fiber Bragg Gratings Written in Multilayer Single Mode Fibers
Zheng Jingjing, Wen Yinghong, Qi Chunhui, Pei Li, Wei Huai, Ning Tigang, and Jian Shuisheng
The optical properties of gratings written in nonperiodical multilayer fibers are investigated both theoretically and experimentally. The coupled-mode theory for gratings is extended to be applicable to the fibers with more than one photosensitive layers. The experimental results of fiber Bragg gratings written in laboThe optical properties of gratings written in nonperiodical multilayer fibers are investigated both theoretically and experimentally. The coupled-mode theory for gratings is extended to be applicable to the fibers with more than one photosensitive layers. The experimental results of fiber Bragg gratings written in laboratory-fabricated ordinary and Er3+ doped multilayer single mode fibers confirm that such gratings possess the common characteristics of the gratings written in ordinary one-layer-core fibers, which indicates that in a device using multilayer fiber as its critical part, gratings written in the multilayer fibers are able to fulfill the requests for grating parts. The experimental results also suggest that the inter-layer stress in core area may be a major cause of photosensitive compensation for hydrogen-loaded Er3+ doped multilayer fiber..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1006002 (2012)
Optical Principle Research of Space Laser Communication Network
Jiang Huilin, Hu Yuan, Ding Ying, Fu Qiang, Zhao Yiwu, Dong Keyan, Song Yansong, and Lou Yan
With urgent demand of the high-resolution observation technology development and the high data rate transmission of information, the research of high-rate laser communication networking technology is imminent. Basic requirement and technical difficulties on the space laser communication networking in realization are anWith urgent demand of the high-resolution observation technology development and the high data rate transmission of information, the research of high-rate laser communication networking technology is imminent. Basic requirement and technical difficulties on the space laser communication networking in realization are analyzed. The new networking optical principle is proposed. A technological solution is studied, which can be used for laser communication through multiple targets at the same time, and an optical antenna of multi-mirror combination is designed based on the paraboloid of revolution, relay optical system, receiving and transmission system and acquisition, pointing, tracking (APT) system. It provides a new technical way for space laser communication network..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1006003 (2012)
Adaptive Step-Size Constant-Modulus Algorithm for High-Speed Optical Coherent Communication System
Di Xuejing, Tong Cheng, Zhang Xia, Zhang Xiaoguang, and Xi Lixia
In coherent detection of a high-speed optical communication system, blind equalization is a common technique to recover transmitted symbols, and one of the most widely used algorithms is constant-modulus algorithm (CMA). But on one hand, it can not converge fast and precisely enough; on the other hand, it can be caughtIn coherent detection of a high-speed optical communication system, blind equalization is a common technique to recover transmitted symbols, and one of the most widely used algorithms is constant-modulus algorithm (CMA). But on one hand, it can not converge fast and precisely enough; on the other hand, it can be caught in singularity problem while operating on a polarization division multiplexed system. A modified CMA, which is adaptive step-size CMA, is proposed. The performance of the proposed algorithm is numerically tested in a 112 Gb/s polarization division multiplexed 16 quadrature amplitude modulation (QAM) optical coherent system. Compared with conventional CMA, the convergence rate of the modified CMA is 20 times faster, and the variance of the error function is 0.7 dB lower. Besides, the modified CMA can overcome the singularity problem quite well. Without considering the singularity problem, the optical signal noise rate (OSNR) penalty is 15 dB lower than that of conventional CMA..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1006004 (2012)
Optical Millimeter-Wave Sub-Carrier Generation Based on Optical Parametric Loop Mirror
Li Hengwen, Jiang Yang, Xu Jing, Zhou Zhuya, and Wang Shunyan
Based on a fiber optical parametric loop mirror (OPLM) and a fiber Bragg grating (FBG), a scheme of 60 GHz optical millimeter-wave sub-carrier generation is analyzed and demonstrated. The conclusion indicates that OPLM can be used to achieve high-order harmonic and pump filter of photonic microwave signals at the same Based on a fiber optical parametric loop mirror (OPLM) and a fiber Bragg grating (FBG), a scheme of 60 GHz optical millimeter-wave sub-carrier generation is analyzed and demonstrated. The conclusion indicates that OPLM can be used to achieve high-order harmonic and pump filter of photonic microwave signals at the same time, then optical millimeter-wave subcarrier can be obtained by leaving only the high harmonics. In the experimental demonstration, utilizing 5 GHz baseband signal, high-order harmonic generation and separation of the pump can be achieved by modulating the nonlinear and four-wave mixing and filtering in OPLM. Eventually, the required 60 GHz optical millimeter-wave sub-carrier signals can be realized successfully. Which shows good performance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1006005 (2012)
Ultra-Wideband Filtering Characteristics of Chirped Long-Period Fiber Gratings with Apodization Optimization
Yang Ying, and Gu Zhengtian
Based on the coupled-mode theory and transfer matrix method, the ultra-wideband filtering characteristics of chirped long-period fiber gratings (LPFG) are analyzed. When the resonant peaks corresponding to different order cladding modes overlap with each other, the transmission spectral bandwidth of chirped LPFG can exBased on the coupled-mode theory and transfer matrix method, the ultra-wideband filtering characteristics of chirped long-period fiber gratings (LPFG) are analyzed. When the resonant peaks corresponding to different order cladding modes overlap with each other, the transmission spectral bandwidth of chirped LPFG can expand to 500 nm, so this chirped LPFG can be used as ultra-wideband band-stop filters. With the increasing of mode order, chirp coefficient, grating length, grating period and refractive index modulation, the transmission spectral bandwidth increases monotonically, but the transmission spectral bandwidth decreases with the increasing of the fiber cladding radius. The refractive index apodization is proposed to inhibit the side-lobes of the transmission spectra. It provides a new method for the design of wideband filters..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1006006 (2012)
Fourier Optics and Signal Processing
Virtual Optical Image Encryption Based on Interference
Qin Yi, Zhang Shuai, Gong Qiong, Li Genquan, and Lü Xiaodong
A virtual optical encryption system is proposed. The system adopts the basic structure of in-line digital holography and the original image is taken as the object to be recorded. Two dependent random phase masks, which act as the encryption and decryption keys, are employed in both the reference light path and the inteA virtual optical encryption system is proposed. The system adopts the basic structure of in-line digital holography and the original image is taken as the object to be recorded. Two dependent random phase masks, which act as the encryption and decryption keys, are employed in both the reference light path and the interference field. The complex field in the hologram plane is the encryption result. The statistical properties of this technique is analyzed. It is shown that the encoding converts the input signal to stationary white noise if the scale coefficient is properly selected. Computer simulations prove the encryption effects and its robustness against brute-force attacks. The influence of noise and additional parameters on the decryption results is studied. The encryption system is not so robust to noise attack, but it is highly sensitive to additional parameters..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1007001 (2012)
Holography
Investigation on Phase Unwrapping in Dual-Wavelength Digital Holography
Wang Yujia, Jiang Zhuqing, Gao Zhirui, Cai Wenyuan, and Wu Jiangtao
Two individual digital holograms are recorded by using two different wavelengths, respectively, and two phase images for the wavelengths are obtained after numerical reconstruction. Subtraction of the two phase images corresponding to two wavelengths can yield a new phase image for the beat wavelength. The final phase Two individual digital holograms are recorded by using two different wavelengths, respectively, and two phase images for the wavelengths are obtained after numerical reconstruction. Subtraction of the two phase images corresponding to two wavelengths can yield a new phase image for the beat wavelength. The final phase image is free of 2π discontinuities after dual-wavelength phase unwrapping. This method is explored by numerical simulation, and then a dual-wavelength digital holographic experimental setup is constructed. In the experiment, two lasers of different wavelengths of 660 nm and 671 nm are used to make phase contrast imaging to a standard quartz flake and a plano-concave lens. Continuous phase images are obtained by dual-wavelength phase unwrapping method. The experimental results are in good agreement with the numerical simulation. The effectiveness of dual-wavelength phase unwrapping is demonstrated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1009001 (2012)
Image Processing
Aero-Optical Imaging Deviation under the Small-Incidence-Angle Condition
Zhang Shijie, Li Junshan, Sun Lihui, and Hu Shuangyan
The non-uniform flow field around the vehicle flying at a high speed bends the incident ray and imposes an imaging deviation on the imaging plane. The relation between the deflection angle and the refractive index gradient is derived theoretically, and a new method is proposed to compute the deflection angle when the rThe non-uniform flow field around the vehicle flying at a high speed bends the incident ray and imposes an imaging deviation on the imaging plane. The relation between the deflection angle and the refractive index gradient is derived theoretically, and a new method is proposed to compute the deflection angle when the ray is passing through the discrete refractive index field with a small incidence angle. Then fluid-dynamics computations under different flying conditions have been completed. After that the mean density field is converted into the refractive index field. Ray tracing is performed to obtain the deflection angle and the gradients along the propagation path. The results show that the computed results by our method are well consistent with those by the Runge-Kutta and the Snell method when the incidence angle is less than 30°; and at the same altitude, the imaging deviation does not grow as the flying speed increases under the small incidence-angle condition, but remains stable; the deflection angle is determined by the positive as well as the negative refractive index gradient region, and the negative refractive index gradient region may reduce the imaging deviation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1001002 (2012)
Imaging Systems
Influence of Structural Defect of Square-Hole Micro Channel Plate on Imaging Quality
Li Xu, He Fei, Li Da, and Chen Bo
As a new X-ray imaging system, more and more attention has been paid to the square-hole micro channel plate (MCP) which has the properties of large field of view, high resolution, and collection of enormous radiation to be collimated or focused. However, during the fabrication and process of the MCP, it is hard to avoiAs a new X-ray imaging system, more and more attention has been paid to the square-hole micro channel plate (MCP) which has the properties of large field of view, high resolution, and collection of enormous radiation to be collimated or focused. However, during the fabrication and process of the MCP, it is hard to avoid generating structural defects in the square holes which greatly influent the imaging quality. The standard square-hole MCP model and MCP models with different structural defects are first set up with the software Tracepro, and then the simulative images of these models are simulated by ray trace method of Monte Carlo. Then the influences of structural defects of Taper type, Twist type and Nonsquare type on imaging quality are analyzed. Based on above simulations, the four samples of MCP are imaged in visible bands with a Nickel-Tungster source. The experimental results are consistent with the simulated images, proving that the simulations are correct. The experimental results show that, all of the three defects can result in area increase and intensity decrease of the central bright spot with expect that the third defect can divide the focused rays into two beams which forms four focus and makes the degradation of energy more serious and thus more seriously influence the imaging quality compared with the other two defects. This paper provides an important basis for the future researches on curved MCP and X-ray optical system based on MCP..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1011001 (2012)
Long Wave Infrared Scene Simulation Research Based on Zero Stadia of Landmark
Hu Haihe, Bai Tingzhu, Guo Changgeng, Han Qiang, Sun Yujie, Cui Jianping, and Zhang Luosha
In order to simulate landmark long wave infrared scene image, according to the variation law of earth surface temperature with time, combining the parameters, such as weather condition, background material, thermal feature parameters, thermal situation and so on, the factors which affect the variation process of earth In order to simulate landmark long wave infrared scene image, according to the variation law of earth surface temperature with time, combining the parameters, such as weather condition, background material, thermal feature parameters, thermal situation and so on, the factors which affect the variation process of earth surface temperature, such as sun radiation, sky long wave radiation, air temperature, earth surface heat conduction, are analyzed. The equation based on the thermal balance theory and heat conduction process is founded, then the temperature variation about some usual earth surfaces in a day is figured out, and the temperature is proposed to be simultaneously used in the corresponding infrared texture image derived from the same visual texture image. By considering the computation model including self radiation, reflected radiation of the scenery, the related earth surface infrared scene with infrared texture detail is created. The results indicate that the method can simulate infrared scene with reality and is valid to simulate landmark long wave infrared feature..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1011002 (2012)
High Resolution Open-Loop Adaptive Optics System for Retinal Imaging Based on Liquid Crystal Spatial Light Modulator
Qi Yue, Kong Ningning, Li Dayu, Xia Mingliang, and Xuan Li
An open-loop adaptive optics system with liquid crystal spatial light modulator and Shark-Hartmann wavefront sensor is constructed. The system is designed according to zero diopter. Compared with the static target, the stability of the pupil increases obviously while staring at the dynamic target during the experiment.An open-loop adaptive optics system with liquid crystal spatial light modulator and Shark-Hartmann wavefront sensor is constructed. The system is designed according to zero diopter. Compared with the static target, the stability of the pupil increases obviously while staring at the dynamic target during the experiment. The impact of individual differences on human eyes has been reduced effectively. The focal plane of the light source can be axial shifted to ensure it can reach the photoreceptors layer of the retina with the help of trial lens. The fundus is illuminated by polarized light and the energy efficiency increases by 20%. The control flow of the system is optimized and the continuous working frequency of the system is above 20 Hz. Four volunteers are participated in the experiments. Both of them obtain the clear photoreceptor images after corrections..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1011003 (2012)
Instrumentation, Measurement and Metrology
An Accurate Method of Measuring Azimuth Based on Sine Wave Magneto-Optic Modulation
Yang Zhiyong, Zhou Zhaofa, Huang Xianxiang, and Zhang Zhili
To solve the problem that the measurement precision of traditional azimuth measurement system based on sine wave magneto-optic modulation polarized light is low, a new model of measuring azimuth is presented to improve the measurement precision. The principle of traditional azimuth measurement system based on sine waveTo solve the problem that the measurement precision of traditional azimuth measurement system based on sine wave magneto-optic modulation polarized light is low, a new model of measuring azimuth is presented to improve the measurement precision. The principle of traditional azimuth measurement system based on sine wave magneto-optic modulation polarized light is analyzed. As the signal from modulator is expressed with the omitted high-order term Bessel function expansions, the method error and truncation error are detected. A new model which does not include theoretic error is presented, and the new model expressed in simplex trigonometric function is established. Simulation results show that the system measurement precision of the new model is obviously higher than the traditional one. It provides a certain reference to apprehend the system principle and improve the system measurement precision..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1012001 (2012)
Crosstalk Analysis and Cancellation Method Study in Stereoscopic Displays
Xia Zhenping, Li Xiaohua, Cui Yuan, and Chen Lei
With the increasing application of stereoscopic displays, the performance of stereoscopic displays attracts more and more attention. Crosstalk is one of the main perceptual factors influence image quality and visual comfort. To eliminate the crosstalk of liquid crystal based stereoscopic displays, based on a novel imagWith the increasing application of stereoscopic displays, the performance of stereoscopic displays attracts more and more attention. Crosstalk is one of the main perceptual factors influence image quality and visual comfort. To eliminate the crosstalk of liquid crystal based stereoscopic displays, based on a novel image processing crosstalk cancellation method is proposed. The proposed method reduces crosstalk from the aspect of the observer, and the light measured when the non-observed channel has the same gray level as the observed channel is defined as the ideal light output of the channel under test. The light output characteristic of specific stereoscopic display is measured using time average luminance meter and look up table is derived for crosstalk reduction. The theoretical calculation results show that the proposed method reduces crosstalk by 75% in average. Besides, the proposed method makes full use of the light leaked from the other eye view, which improves the luminance by about 12% according to the experiment. The proposed method can be applied both on time-multiplexed and on spatial-multiplexed stereoscopic display technologies and is easily implemented..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1012002 (2012)
Track-Before-Detect Algorithm Based on Probability Hypothesis Density Smoother
Lin Zaiping, Zhou Yiyu, An Wei, and Xu Yang
Track-before-detect (TBD) technology based on the probability hypothesis density (PHD) filter can effectively solve the problem of tracking number-varying dim multi-target. The main limitation of the standard PHD-TBD algorithm is the estimation error of target numbers influenced by the measurement noise remarkably. An Track-before-detect (TBD) technology based on the probability hypothesis density (PHD) filter can effectively solve the problem of tracking number-varying dim multi-target. The main limitation of the standard PHD-TBD algorithm is the estimation error of target numbers influenced by the measurement noise remarkably. An improved PHD-TBD algorithm based on the smooth is proposed. The algorithm can overcome the influence of noise in a certain extent by updating the weight of particle using forward recursion and backward smooth, and then a steady estimation of target numbers is obtained. In addition, the simulation results demonstrate that the proposed algorithm can effectively and stably estimate the number of targets and their positions comparing with the standard one..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1012003 (2012)
Self-Check Target for Shock-Wave Experiment with Radiation Drive Source
Wang Feng, Chen Ming, Peng Xiaoshi, Liu Shenye, Xu Tao, and Wei Huiyue
The shock-wave velocity can be obtained with two-sensitivity method on the measurement of shock-wave velocity with imaging velocity interferometric system for any reflector (VISAR) . Since the decision difference for shock-wave velocity, the velocity curve may be not unique. This problem will be serious due to the effeThe shock-wave velocity can be obtained with two-sensitivity method on the measurement of shock-wave velocity with imaging velocity interferometric system for any reflector (VISAR) . Since the decision difference for shock-wave velocity, the velocity curve may be not unique. This problem will be serious due to the effect of speckle and decrease of fringe pattern. The new method for target design is provided. After comparing the area of shock-wave velocity and the thickness of transparent window, the shock-wave velocity can be confirmed. And the uncertainty of VISAR system can be achieved which is agreement with the theoretical prediction. This method, which presents the shock wave velocity and uncertainty of VISAR, provides the new way for accurate diagnosis by VISAR system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1012004 (2012)
Integrated Optics
Analysis on Performances of Several Polymer Bent Waveguide Based on Asymmetric Ridge Waveguide
Gao Yuan, Zhang Xiaoxia, and Liao Jinkun
In order to reduce length of the branch waveguide in Mach-Zehnder (M-Z) electro-optic modulator, the organic polymer ridge waveguide with asymmetric structure is applied in S-bend waveguide. Using the semi-vector finite-difference beam propagation method (FD-BPM), the transition loss of TM00 optical field is systematicIn order to reduce length of the branch waveguide in Mach-Zehnder (M-Z) electro-optic modulator, the organic polymer ridge waveguide with asymmetric structure is applied in S-bend waveguide. Using the semi-vector finite-difference beam propagation method (FD-BPM), the transition loss of TM00 optical field is systematically studied in three conventional bend waveguides, namely sine-bend, arc-bend and cosine-bend, under different parameters, which is compared with the S-bend waveguide using symmetric ridge waveguide structure. The research results show that the lengths of sine, arc and cosine branch waveguides could be reduced by 40%, 30% and 25% respectively in the same transmission loss conditions, when the structure parameters are core height h=1.5 μm, ridge width w=4 μm, branch height G=11 μm and ridge height is 0.3 μm, in the case of short core width s≥2 μm. The results will have some reference value to the design of optical waveguide in M-Z modulator..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1013001 (2012)
Machine Vision
Infrared Dim Small Target Detection Based on Morphological Band-Pass Filtering and Scale Space Theory
Cheng Gong, Guo Lei, Han Junwei, and Qian Xiaoliang
A novel approach is proposed to detect infrared dim target from cluttered background by using morphological band-pass filtering and scale space theory. The infrared image is pre-processed by means of morphological band-pass filter, which results in regions of interest (RoI) containing dim small targets. Then, differencA novel approach is proposed to detect infrared dim target from cluttered background by using morphological band-pass filtering and scale space theory. The infrared image is pre-processed by means of morphological band-pass filter, which results in regions of interest (RoI) containing dim small targets. Then, difference-of-Gaussian function is adopted to obtain scale space of pre-processed infrared image. Scale space maximum detection is then performed to generate candidate targets with their positions and scales. Infrared dim small target detection is achieved by using thresholding signal-to-clutter ratio of candidate targets. Experimental results on real-world infrared images and comparisons with state-of-the-art methods can demonstrate the effectiveness and robustness of the proposed approach..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1015001 (2012)
Calibration for Gaze Tracking System Based on Binocular Stereo Vision
Wen Qingchuan, Da Feipeng, and Fang Xu
To solve the limitation in the gaze tracking system using active infrared light, a gaze tracking system under the condition of natural light allowing the human head moves freely is constructed. Binocular stereo vision method is employed to obtain the characteristic parameters of eyes, and then the sight line can be estTo solve the limitation in the gaze tracking system using active infrared light, a gaze tracking system under the condition of natural light allowing the human head moves freely is constructed. Binocular stereo vision method is employed to obtain the characteristic parameters of eyes, and then the sight line can be estimated. The head pose can be estimated by using headset calibration board and the error caused by head moving can be reduced. Then a calibration method of individual parameters in gaze tracking system is proposed. This method assumes the optical axis is coincided with the line of sight. Then the center and radius of eyeball, the angle between eye optical axis and visual axis can be calculated. The optimal parameters can be obtained by employing the nonlinear optimization algorithm to process the initial estimate values. Experiment results verify that the proposed method is almost unconstrained, and the estimation accuracy of sight line is high. So this method can satisfy the need of gaze tracking system in many cases..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1015002 (2012)
Materials
Optical Properties and Fluorescence Modification of the Sandwich Structure Composed of Ultra-Thin Gold films, Light-Emitting Layers and Photonic Crystals
Chen Yuanhao, Liu Guiqiang, Gong Lixia, Tang Falin, Li Lei, and Huang Kuan
Sandwich structures composed of an ultra-thin gold film, a light-emitting layer and a three-dimensional (3D) photonic crystal (PC) are fabricated by the vertical deposition method and spin-coating method. Attenuated total reflection measurements show that the 3D PC plays a crucial role in the formation of significant oSandwich structures composed of an ultra-thin gold film, a light-emitting layer and a three-dimensional (3D) photonic crystal (PC) are fabricated by the vertical deposition method and spin-coating method. Attenuated total reflection measurements show that the 3D PC plays a crucial role in the formation of significant optical properties. For the sandwich structure with a high-quality 3D PC, two reflection troughs are clearly observed at the incidence angles of 48° and 63°, while the reflection troughs disappear in the attenuated total reflection curves of the sandwich structures for those with a low-quality 3D PC. Compared with the two-layer structures of ultra-thin gold film and light-emitting layer, pronounced changes are found in the curves of the fluorescence properties of the sandwiches, the single emitting peak at 600 nm of quantum dots (QDs) is split into two peaks, and the intensity of peak positioned at 600 nm is weaker than that positioned at 620 nm by 30%..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1016001 (2012)
Analysis of Ultraviolet Radiation Characteristics of Solid Propellant Rocket Motor Exhaust Plume
Guo Aiyan, Bai Tingzhu, Hu Haihe, and Tang Yi
To study the effect of propellant type and content of aluminum powder on the ultraviolet radiation of solid rocket motor plume, a plume ultraviolet radiation model is build, using two-dimensional flow-field and three-dimensional radiation transfer calculation, taking thermal emitting, CO+O chemiluminescence, OH radicalTo study the effect of propellant type and content of aluminum powder on the ultraviolet radiation of solid rocket motor plume, a plume ultraviolet radiation model is build, using two-dimensional flow-field and three-dimensional radiation transfer calculation, taking thermal emitting, CO+O chemiluminescence, OH radical chemiluminescence, Al2O3 particles of different crystalline states and diameters into consideration. The ultraviolet radiation distributions of double base, modified double base and composite propellant rocket motor plume are calculated, and the effect of aluminum powder content on plume ultraviolet radiation is analyzed, taking composite propellant as an example. This study can provide reference for the judgment of missile type in the process of early warning, as well as improvement of missile ultraviolet stealth performance..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1016002 (2012)
Properties of All-Optical Switch Based on Two-Dimensional Nonlinear Photonic Crystals
Yang Hui, Wang Zhiyong, Zhang Wei, and Wang Wenchao
To obtain an optimum structure of all-optical switch, based on 90° photonic-crystal bend waveguide, an improved photonic crystal structure with Kerr nonlinear dielectric rods is introduced. By means of finite difference time domain (FDTD), the numerical analysis shows that this switch can achieve the following perTo obtain an optimum structure of all-optical switch, based on 90° photonic-crystal bend waveguide, an improved photonic crystal structure with Kerr nonlinear dielectric rods is introduced. By means of finite difference time domain (FDTD), the numerical analysis shows that this switch can achieve the following performance: bandwidth (about 50 nm), high extinction ratio (>40 dB), threshold power density (5.2 W/μm). At the same time, it can also implement fundamental logical functions..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1016003 (2012)
Preparation of Ge30Sb8Se62 Chalcogenide Glass and Designing for a Low-Loss Hollow-Core Photonic Crystal Fiber at 10.6 μm
Liu Yongxing, Zhang Peiqing, Xu Yinsheng, Wang Xunsi, Dai Shixun, Nie Qiuhua, and Xu Tiefeng
Chalcogenide glass photonic crystal fiber is expected to have important applications in the field of mid-infrared laser transmission. The Ge30Sb8Se62 chalcogenide glass with excellent transparency in mid-infrared region is prepared. Based on this chalcogenide glass, a band-gap photonic crystal fiber is designed, which Chalcogenide glass photonic crystal fiber is expected to have important applications in the field of mid-infrared laser transmission. The Ge30Sb8Se62 chalcogenide glass with excellent transparency in mid-infrared region is prepared. Based on this chalcogenide glass, a band-gap photonic crystal fiber is designed, which suits high power laser transmission. With plane wave expansion method and finite element method, photonic band gap, mode-field area and confinement loss of the designed photonic crystal fiber are systematically studied. By optimizing the structural parameters of fiber, photonic crystal fiber with confinement loss less than 0.1 dB/m and effective mode-field area larger than 100 μm2 at 10.6 μm is obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1016004 (2012)
Medical Optics and Biotechnology
Monte Carlo Simulation of Light Propagation Along the Pericardium Meridian Line at the Wrist
Jiang Yifan, Chen Changshui, Liu Rongting, and Liu Songhao
The characteristic of light transportation along the pericardium meridian line and its surrounding areas at the wrist is studied by using Monte Carlo method. Three simplified models for Monte Carlo simulation are built based on the anatomical structure. The light propagation along the pericardium meridian line, the tenThe characteristic of light transportation along the pericardium meridian line and its surrounding areas at the wrist is studied by using Monte Carlo method. Three simplified models for Monte Carlo simulation are built based on the anatomical structure. The light propagation along the pericardium meridian line, the tendon and the non-meridian line nearby are simulated separately. The simulation results show strong accordance with the previous experimental results that the light propagation along the pericardium meridian has an advantage over its surrounding areas at the wrist. Luminous flux in different layers on the three paths are calculated, and the results show that the optical transmission characteristics in this region is mainly affected by its underlying structure and its underlying tissue composition. Besides, light transportation in the underlying tissue of the pericardium meridian line also has an advantage and the advantage transmission significantly correlates with the closed anatomical structure of the underlying tissue..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1017001 (2012)
Tumor Suppressor Gene p53 of Single Cell Fourier Transform Infrared Microspecroscopy
Yan Jingwen, Jiang Shiping, and Chen Liang
In order to explore the capability of Fourier transform infrared microspecroscopy in discriminating single gene difference in single cell, synchrotron Fourier transform infrared microspecroscopy is used to measure single cell spectra of colorectal cancer cells with and without tumor suppressor gene p53, respectively. WIn order to explore the capability of Fourier transform infrared microspecroscopy in discriminating single gene difference in single cell, synchrotron Fourier transform infrared microspecroscopy is used to measure single cell spectra of colorectal cancer cells with and without tumor suppressor gene p53, respectively. With comparison of spectra of these two types of cancer cells, absorption intensities and frequencies of lipids, proteins and nucleic acids are evidently different. The absorption bands of single cell without p53 are weak and almost all the peaks drift to higher wavenumbers. Absorption intensity ratio of amide I/amide II increases significantly in the cell without p53, indicating the secondary structures of proteins change. The fitting analysis of amide I absorption band reveals that contents of α helix and random coil in secondary structures of proteins in cell with p53 gene are lower than that in cell without p53, and contents of turns and atypical helix are higher in cell with p53. However, content of β-sheet in both cell is very similar. The results demonstrate that the absence of single gene p53 can affect metabolism activity, which can be clarified by synchrotron Fourier transform infrared microspecroscopy at molecular level..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1017002 (2012)
Microscopy
Multiple Variational Field-of-View Multifocal Multiphoton Fluorescence Microscope
Li Zhen, Qu Junle, Shao Yonghong, and Gao Zhi
A novel multifocal multiphoton excited fluourescence microscopy (MMM) is presented. The required focus array can be produced in multiple interesting subregions through uploading the accurate phase pattern to the spatial light modulator (SLM) with the software. The focus array can be scanned with a two-mirror galvo scanA novel multifocal multiphoton excited fluourescence microscopy (MMM) is presented. The required focus array can be produced in multiple interesting subregions through uploading the accurate phase pattern to the spatial light modulator (SLM) with the software. The focus array can be scanned with a two-mirror galvo scanner by scanning the single beam that is incident on the SLM. The two photon fluorescence signal is recorded directly with an electron-multiplying CCD in parallel. The two photon fluorescence images in the whole field-of-view are obtained under the different modes such as 10×10 and 50×50 arrays, and the multiple subregions of interest are addressably excited simultaneously. Compared with the other MMMs, our MMM has a good flexibility without sacrificing of the imaging speed and spatial resolution and also without hardware changes..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1018001 (2012)
Optical Design and Fabrication
Theoretical Calculation of Telescope Primary Mirror′s Thermal Field and Seeing Analysis of Primary Mirror
Zhang Jun, Xian Hao, He Yuanxing, and Rao Changhui
A temperature field theoretical model of classical telescope primary mirror is presented. Analytical solution is gotten by separation of variables and Green′s function method. It is easy to get the temperature difference between primary mirror work surface and ambient air with the analytical solution of the temperatureA temperature field theoretical model of classical telescope primary mirror is presented. Analytical solution is gotten by separation of variables and Green′s function method. It is easy to get the temperature difference between primary mirror work surface and ambient air with the analytical solution of the temperature field. A quantitative analysis of the primary mirror seeing is addressed. The relationship between primary mirror seeing and the size of primary mirror is studied in two different materials (fused silica and BK7) and two different kinds of mirror (traditional mirror and thin mirror) in two definite conditions with analytic solution. For 4 m traditional mirror and thin mirror, the relationship between primary mirror seeing and descending slope of the ambient air temperature is also presented. The quantitative analysis is helpful for estimating primary mirror seeing. The analytical solution of primary mirror is also valuable in designing telescope primary mirror for calculating thermal stress and thermal strain..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1022001 (2012)
A High Flux Solar Simulator Based on an Array of Non-Coaxial Ellipsoidal Reflector
Ren Lanxu, Wei Xiudong, Niu Wenda, Wang He, Xu Wenbin, Xiao Jun, and Lu Zhenwu
To get a high-flux and high-uniformity spot in the target of solar simulator, the design and optimization of reflector are needed. Using non-coaxial ellipsoidal reflector to improve the quality of spot, the flux uniformity of spot is improved obviously. By using Monte-Carlo ray tracing method, a high flux concentratingTo get a high-flux and high-uniformity spot in the target of solar simulator, the design and optimization of reflector are needed. Using non-coaxial ellipsoidal reflector to improve the quality of spot, the flux uniformity of spot is improved obviously. By using Monte-Carlo ray tracing method, a high flux concentrating solar simulator is designed. The target of 80 mm diameter can receive 10 kW radiative power on the second focal plane. The symmetry and uniformity of radiative spot are good, and the transfer efficiency of system from source to target is 23.81%. The average flux is 2 MW/m2 in the 80 mm diameter target and the flux can get 3.64 MW/m2 in the 50 mm diameter target which corresponds to a theoretical stagnation temperature of 2800 K. Non-coaxial ellipsoidal reflector is used to manufacture a solar simulator making up of supply control system, cooling system, xenon lamps and a condenser system. The focusing spot of solar simulator obtained in experiment test accords with the model spot by optical design simulation software TracePro..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1022002 (2012)
A Switch Zoom Design for Reflective Laser Beam Expander
Jia Yong, and Gao Yunguo
Reflective beam expanders are widely used for high-power laser launchers. However, compared with refractive expander, it is harder to realize zoom effects because of off-axis. This paper focuses on a new program, using one piece of main mirror and two different secondary mirrors to change the magnification of expandersReflective beam expanders are widely used for high-power laser launchers. However, compared with refractive expander, it is harder to realize zoom effects because of off-axis. This paper focuses on a new program, using one piece of main mirror and two different secondary mirrors to change the magnification of expanders, and a system is designed to expand a CO2 laser beam from 54 mm diameter to 81 mm (1.5×) and 162 mm (3.0×) in the state of off axis. The simulation results indicate that this kind of design is of great practicality with almost the same modulation transfer function (MTF) curves as a maladjusted telescope, having the same order of magnification with commonly used expanders. After compensating the defocus amount, the system′s imaging achieves the diffractive limit..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1022003 (2012)
Design of Extra Wide Short Wave Infrared Spectral Imager′s Fore-Optics
Zhong Xing, and Jin Guang
To increase working efficiency of airborne short wave infrared (SWIR) push-broom spectral imagers and acquire wider coverage, a fore-optics with 90° field of view (FOV) is researched. A new-style tilted component reflective system is put forward to avoid descending of transmittance at long waveband in traditional To increase working efficiency of airborne short wave infrared (SWIR) push-broom spectral imagers and acquire wider coverage, a fore-optics with 90° field of view (FOV) is researched. A new-style tilted component reflective system is put forward to avoid descending of transmittance at long waveband in traditional refractive SWIR fore-optics working in 1～2.5 μm. Three-order aberrations correction of tilted component system is briefly introduced. Based on initial configuration solving, a 15 mm focal length, 1/3.5 relative aperture, 90° FOV reflective fore-optics with tilted components is designed, whose distortion is optimized while remain telecentric. Its average modulate transfer function (MTF) at Nyquist frequency is more than 0.68, and relative illumination of margin field achieves 88%. Besides, there is no transmittance descending caused by material absorption. Push-broom image with fore-optics′ distortion is simulated. The optical design can be applied in SWIR spectral imagers with wide FOV and enhance system′s detection sensitivity extremely..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1022004 (2012)
Light Field Microscope to Achieve Three-Dimensional Real-Time Naked-Eye Display
Dai Zhihua, Xu Yuping, Bu Jing, Yang Yong, Zhao Xing, and Yuan Xiaocong
Combining light field microscope and naked-eye three-dimensiional display technique, a new method to realize real-time naked-eye observation of micro-specimen in a light field microscope is proposed. The sub-image array obtained by a light field microscope is projected on the focal plane of microlens array directly. ObCombining light field microscope and naked-eye three-dimensiional display technique, a new method to realize real-time naked-eye observation of micro-specimen in a light field microscope is proposed. The sub-image array obtained by a light field microscope is projected on the focal plane of microlens array directly. Observers can see two perspective views of the specimen at the same time in a certain region and feel stereo effect because of binocular. The proposed method has advantageous properties including simple configuration, no requirement of coherent light source and allowing many people observing at the same time without wearing special glasses, and thus it has an important prospect of application..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1022005 (2012)
Freeform Reflector Design for Rectangular Illuminance Distribution Based on Differential Geometry
Liu Zhengquan, Sun Yaojie, and Lin Yandan
A freeform reflector design method, which is mainly based on a first-order linear partial differential equation, is proposed for uniform rectangular illuminance distribution in the field of LED illumination. The interaction between the freeform surface and the light beam is depicted based on theory of the differential A freeform reflector design method, which is mainly based on a first-order linear partial differential equation, is proposed for uniform rectangular illuminance distribution in the field of LED illumination. The interaction between the freeform surface and the light beam is depicted based on theory of the differential geometry and Snell′s law. The energy topological relation between the Lambertian luminaire and the illuminated rectangular surface is established according to the LED luminous intensity distribution. The method deducts a first-order linear partial differential equation with some boundary conditions to represent the freeform reflector. The boundary conditions and the partial differential equation are solved by the Runge-Kutta method and finite difference method, respectively. The numerical results are validated in the form of raytracing, which reveal that the luminous flux efficiency is about 94%, the transverse uniformity of illuminance on the target surface is 0.9 and the longitudinal uniformity of illuminance on the target surface is 0.8. The numerical computation time is less than 1 s..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1022006 (2012)
Design of Quasi-Phase Photon Sieve
Tang Yan, Hu Song, Zhu Jiangping, and He Yu
A design of quasi-phase photon sieve is proposed. The pinholes of the quasi-phase photon sieve distributed in black and white plate zones have different ratios of diameter to zone width to obtain π phase shift, so that all of them have positive contribution to the field value at the desired focal point. The quasi-phaseA design of quasi-phase photon sieve is proposed. The pinholes of the quasi-phase photon sieve distributed in black and white plate zones have different ratios of diameter to zone width to obtain π phase shift, so that all of them have positive contribution to the field value at the desired focal point. The quasi-phase photon sieve does not need to process the rest and reduce the technology difficult of traditional phase photon sieve. Compared with the traditional photon sieve, the quasi-phase one with the same specific minimum feature size has bigger numerical aperture and smaller focal spot size. Furthermore, compared with the multi-region photon sieve, with the same specific minimum feature size and numerical aperture, the quasi-phase photon sieve has smaller focal spot size and better focus characteristics. The quasi-phase photon sieve provids a new way for the design of photon seieve with high humerical aperture..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1022007 (2012)
Optical Devices
Application of Focusing Capillary in Extreme Ultraviolet Collimator
Zhou Yuanyuan, Zhou Sizhong, and Deng Ying
Through using focusing capillary, the extreme ultraviolet (EUV) light source of collimator is channelled out of flange, and the light beam′s divergence angle is controlled to match the collimator′s aperture angle. This article analyzes and calculates the case of directly using a light source to illuminate target disk aThrough using focusing capillary, the extreme ultraviolet (EUV) light source of collimator is channelled out of flange, and the light beam′s divergence angle is controlled to match the collimator′s aperture angle. This article analyzes and calculates the case of directly using a light source to illuminate target disk and the light beam cannot cover the diameter of the effective primary mirror. Focusing capillary can make the light beam cover the aperture angle of collimator and the two states of the EUV collimator with and without capillary are tested.The results show that using focusing capillary can expand light beam′s divergence angle. Besides, the maximum number of photons without capillary is close to 1×105 and the maximum number of photons with capillary can reach 1×104. The testing data show that the EUV focusing capillary′s transmission efficiency can achieve 10% to meet technical index of EUV collimator..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1023001 (2012)
Quantum Optics
Quantum Properties in the System of Atoms Interacting with Weak Coherent Cavities Fields
Lu Daoming
Quantum properties of the system comprising two two-level atoms and resonant interaction with two coupled cavities which are in weak coherent states initially are studied. The atomic dipole squeezing is investigated. The results obtained using the numerical method show that atomic dipole squeezing is weakened with the Quantum properties of the system comprising two two-level atoms and resonant interaction with two coupled cavities which are in weak coherent states initially are studied. The atomic dipole squeezing is investigated. The results obtained using the numerical method show that atomic dipole squeezing is weakened with the increase of the coupling constant of the coupled cavities. On the other hand, atom-atom entanglement is also weakened with the increase of the coupling constant of the coupled covities, and this result is contrary to that of the case that the coupled cavities are in vacuum state initially..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1027001 (2012)
Ion Heating by Thermal Noise of Planar Grooved Ion Chip
Ji Weibang, Cheng Huadong, and Liu Liang
The ion heating by voltage fluctuation noise in grooved planar ion trap is investigated. The direct method is used to calculate the ion heating and the length scale is obtained. The variation of length scale with ratio between width of groove and radio frequency electrode varied is calculated by using finite element meThe ion heating by voltage fluctuation noise in grooved planar ion trap is investigated. The direct method is used to calculate the ion heating and the length scale is obtained. The variation of length scale with ratio between width of groove and radio frequency electrode varied is calculated by using finite element method. And then the ion heating by resistance thermal fluctuation of control electrodes is also calculated by using fluctuation dissipation theorem. The spectral density of electric field fluctuation in x and y direction and better value of α are obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1027002 (2012)
Spectroscopy
Theory and Method for Designing Field-Widened Prism of Spatial Heterodyne Spectrometer
Feng Yutao, Bai Qinglan, Wang Yongmei, Hu Bingliang, and Wang Shu′na
It is one of the most important methods to use field-widened prism to increase the throughput or sensitivity for spatial heterodyne spectrometer. This paper borrows idea from the basic principle of traditional Fourier transform spectrometer with field-widened and combines the characteristics of spatial heterodyne spectIt is one of the most important methods to use field-widened prism to increase the throughput or sensitivity for spatial heterodyne spectrometer. This paper borrows idea from the basic principle of traditional Fourier transform spectrometer with field-widened and combines the characteristics of spatial heterodyne spectroscopy, a method based on numerical reduction to design the field-widen prism of spatial heterodyne spectrometer is proposed. The optimum apex angle of field-widened prism and the maximum field are analyzed with certain Littrow angles and scene wave-numbers. The results indicate that numerical induction method can find the optimum solution of prism apex angle by judging the effect of all orders of field angle on the phase difference. Compared with the results obtained by theoretical deduce method, the maximum field angle along dispersive principal cross section increases by 10%~30%, and the numerical induction method is simple and obvious, the influencing factors on the maximum field angle can be analyzed in the process of optimizing field-widened prism angle..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1030001 (2012)
Application of Correlative Analysis with an Alterable and Scannable Window in Spectral Automatic Recognition Laser-Induced Breakdown Spectroscopy
Liu Lituo, Liu Jianguo, Zhao Nanjing, Wang Yin, Wang Chunlong, Shi Huan, Ma Mingjun, Chen Dong, Zhang Yujun, and Liu Wenqing
The width of spectral line acquired by laser induced breakdown spectroscopy (LIBS) is narrow. Spectrometer exists wavelength shift as the temperature of external environment is changing. The discrete digital spectral data is influnced by noise, spectral overlap, and continued background emission. The signal has distortThe width of spectral line acquired by laser induced breakdown spectroscopy (LIBS) is narrow. Spectrometer exists wavelength shift as the temperature of external environment is changing. The discrete digital spectral data is influnced by noise, spectral overlap, and continued background emission. The signal has distortion and deformation. The method of spectral line recognition in current spectrometer software is maily the principle of proximity which results in high error rate and depends on people′s observation. Considering this problem, based on the study of characteristic of LIBS, A method of correlative analysis with an alterable and scannable window (CAASW) is presented in spectral automatically recognition of laser-induced breakdown spectroscopy. In experiment, using soil sample, the process of the method is analyzed and the results are evaluated. Compared with the spectral recognition software of spectrometer, the CAASW is more exact and less time spending, and it can recognize spectral lines automatically..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1030002 (2012)
Thin Films
Optical Characteristics of Silicon Thin Film in Short-Wave Infrared Band and 1.30 μm Bandpass Optical Filter
Duan Weibo, Zhuang Qiuhui, Li Daqi, Chen Gang, Yu Deming, and Liu Dingquan
Silicon material can be used as optical thin films in short-wave infrared (1~3 μm) range, because of its characteristics such as high refractive index, good transparence, easy to match with other layers. Using advanced Sellmeier model, the optical characteristics of silicon thin films have been fitted and calculated. BSilicon material can be used as optical thin films in short-wave infrared (1~3 μm) range, because of its characteristics such as high refractive index, good transparence, easy to match with other layers. Using advanced Sellmeier model, the optical characteristics of silicon thin films have been fitted and calculated. Based on the result, silicon and silicon dioxide are selected as layer materials, and a bandpass filter is designed and fabricated. The center wavelength is about 1.30 μm; the filter with 2 cavities has 32 nm bandwidth and 85.8% transparence at the peak. Combining silicon layers′ high absorption at wavelengths smaller than 1.0 μm, the cut-off range can cover the spectrum range smaller than 1.75 μm..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1031001 (2012)
Design and Fabrication of the Multilayer Film of Enhancing Spectral-Purity in Extreme Ultraviolet
Zhu Wenxiu, Jin Chunshui, Kuang Shangqi, and Yu Bo
Extreme ultraviolet lithography (EUVL) has been regarded as a promising lithographic technology for the 22 nm hp node. It takes advantage of the light of extreme ultraviolet (EUV) whose wavelength is 13.5 nm. But in the 160~240 nm band, laser produced plasma light source spectral intensity, photoresist sensitivity and Extreme ultraviolet lithography (EUVL) has been regarded as a promising lithographic technology for the 22 nm hp node. It takes advantage of the light of extreme ultraviolet (EUV) whose wavelength is 13.5 nm. But in the 160~240 nm band, laser produced plasma light source spectral intensity, photoresist sensitivity and the reflectivity of multilayers are relatively large in the EUVL. The exposure of photoresist will reduce the lithographic quality in the out-of-band. It demonstrates that both theoretically and experimentally, coating the SiC layer on the Mo/Si multilayer can effectively suppress the out-of-band radiation. Designing and fabricating ［Mo/Si］40 SiC multilayers take advantage of X-ray diffraction, spectroscopic ellipsometry, vacuum ultraviolet (VUV) spectrophotometer to determine the thickness and optical constants of thin films and the reflectivity of multilayers. The reflectivity of the out-of-band reduces to 1/5, while the reflectivity of in-band only 5% reduction..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1031002 (2012)
Measurement of Group Delay Dispersion of Dispersive Mirror Based on White-Light Interference
Li Chengshuai, Shen Weidong, Zhang Yueguang, Fan Huanhuan, and Liu Xu
A novel white-light interferometric method based on window Fourier transform and cubic spline interpolation algorithm is proposed for accurate measurement of group delay dispersion of dispersive mirror applied in ultrafast laser system. Numerical simulations indicate that the proposed method exhibits precision up to 0.A novel white-light interferometric method based on window Fourier transform and cubic spline interpolation algorithm is proposed for accurate measurement of group delay dispersion of dispersive mirror applied in ultrafast laser system. Numerical simulations indicate that the proposed method exhibits precision up to 0.58 fs2. After analyzing the effect of Gaussian noise and averaging effect of light intensity on the test accuracy of the above method, home-made Gires-Tournois interferometer mirrors and chirped mirrors are measured. The experimental results demonstrate that group delay dispersion errors are less than 10 fs2 in a wide spectral range. It is concluded from numerical simulations and experimental results that the proposed method can obtain phase information of thin films correctly and quickly, and it is more precise and practical than other algorithms..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1031003 (2012)
Model of Stress Evolution in Polycrystalline Oxide and Composite Thin Films
Li Jingping, Fang Ming, He Hongbo, Shao Jianda, Fan Zhengxiu, and Li Zhaoyang
A model in terms of relaxation process of film structure is developed for stress evolution in polycrystalline thin films. And the growth stress model of composite films is given by linear combination. HfO2 film, SiO2 film and a composite film are prepared by electron-beam evaporation. And stress evolution is obtained bA model in terms of relaxation process of film structure is developed for stress evolution in polycrystalline thin films. And the growth stress model of composite films is given by linear combination. HfO2 film, SiO2 film and a composite film are prepared by electron-beam evaporation. And stress evolution is obtained by in situ wafer curvature measurement. All experimental results are analyzed through model fitting..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1031004 (2012)
Determination of Chemical Bond of Tetrahedral Amorphous Carbon Films by an Ellipsometry Approach
Li Xiaowei, Zhou Yi, Sun Lili, and Wang Aiying
Tetrahedral amorphous carbon (ta-C) films under different substrate negative bias are prepared by a home developed filtered cathodic vacuum arc (FCVA) technology with double bend shape. The film thickness is measured by a combined spectrophotometry and spectroscopic ellipsometry (SE) approach; the chemical bonds includTetrahedral amorphous carbon (ta-C) films under different substrate negative bias are prepared by a home developed filtered cathodic vacuum arc (FCVA) technology with double bend shape. The film thickness is measured by a combined spectrophotometry and spectroscopic ellipsometry (SE) approach; the chemical bonds including sp2C and sp3C are gained by the fitted ellipsometry method. Furthermore, the accuracy of ellipsometry results is evaluated by comparing with those of X-ray photoelectron spectroscopy (XPS) and Raman spectra. The results indicate that the minimum thickness of ta-C film of 33.9 nm is obtained when the bias voltage is -100 V; with the increase of bias voltage, the optical gaps and the content of sp3C atomic bond decrease, while the sp2C content increases correspondingly. By comparison with the results of XPS and Raman spectra, it is found that when the optical constants of sp2C model are represented by the glassy carbon and the fitting wavelength ranges are chosen from 250 to 1700 nm, the best fitting result of atomic bonds of ta-C films can be deduced by the ellipsometry method. Therefore, it could be said that the elliposometry method is a quite promising method to characterize the atomic bonds of ta-C films including sp2C and sp3C, as a new nondestructive, fast, quantitative and easy way..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 32, Issue 10, 1031005 (2012)
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