Contents
2013
Volume: 33 Issue 11
49 Article(s)
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Atmospheric Optics and Oceanic Optics
Light Scattering Analysis of an Asymmetrical Two-Component Aerosol Particle Model
Zhang Xiaolin, Huang Yinbo, and Rao Ruizhong
Orientation-averaged optical characteristics of single aerosol particles are needed for precise modeling of radiative processes in the Earth′s atmosphere. Optical properties of internal-mixed urban aerosols with the sulfate coated on black carbon are studied based on discrete dipole approximation for the size parameterOrientation-averaged optical characteristics of single aerosol particles are needed for precise modeling of radiative processes in the Earth′s atmosphere. Optical properties of internal-mixed urban aerosols with the sulfate coated on black carbon are studied based on discrete dipole approximation for the size parameters from 0.1 to 25. Effects of the internal topology on particulate properties are also performed by changing the position of black carbon. Significant influences are observed for the extinction, scattering, backscattering efficiency factors, asymmetry parameters, extinction-to-backscattering ratios and single scattering albedos of the internal-mixed particles. These influences are relatively small for the size parameter less than 1 while those are large for size parameter more than 1. Meanwhile only the scattering phase function in Rayleigh scattering region and linear polarization in Rayleigh scattering region except the scattering angles near 0° and 180° are almost irrespective of the black carbon position. Smaller black carbon corresponds to weaker effects of black carbon positions on the extinction, scattering and backscattering efficiency factors. Shorter distance of black carbon from the boundary of mixtures with the same size parameter is accompanied by larger single scattering albedos and lower absorption efficiency factors associated with the lensing effect. Small black carbon or large size parameter has the more evident lensing effect related to internal-mixed particles with short distance of black carbon from the center of mixtures with the same size..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1101001 (2013)
Second-Order Statistics for Wave Reflected by a Plane Mirror with a Finite Aperture
Wang Liguo, Wu Zhensen, and Wang Mingjun
Based on complex Gaussian-function expansion method, the transmitting wave is decomposed into a series of Gaussian beam components. ABCD ray-matrix theory combined with Rytov approximation is used to derive the expressions of the mean intensity and the backscattering enhancement coefficient of the reflected wave from aBased on complex Gaussian-function expansion method, the transmitting wave is decomposed into a series of Gaussian beam components. ABCD ray-matrix theory combined with Rytov approximation is used to derive the expressions of the mean intensity and the backscattering enhancement coefficient of the reflected wave from a finite circular mirror in the atmospheric turbulence, which reveals the existence of the oscillation zone. The degree of coherence function and coherence length are calculated and the results prove that the turbulence in the oscillation zone has a larger effect on the wave front..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1101002 (2013)
Detectors
Study on Characteristic Performance of a MCP-Based Photon-Counting Imaging Detector
Ni Qiliang
A two-dimensional photon-counting imaging detector with induced charge wedge-strip anode in extreme ultraviolet (EUV) region is developed based on the maximal operating temperature of 70 ℃ for CE-3 EUV camera, which will be applied to the characteristic performance test at 70 ℃. The detector is mainly composed of microA two-dimensional photon-counting imaging detector with induced charge wedge-strip anode in extreme ultraviolet (EUV) region is developed based on the maximal operating temperature of 70 ℃ for CE-3 EUV camera, which will be applied to the characteristic performance test at 70 ℃. The detector is mainly composed of microchannel plate (MCP) stacks operating in pulse-counting mode, wedge-strip position-sensitive anode and correlative analog and data processing circuit. A three-electrode wedge-strip induced-charge position-sensitive anode with 1.5-mm period and 47-mm diameter active area is designed and fabricated, and front-end analog and data circuit with the maximum rate of 200 kHz is also developed. In order to obtain MCP stack′s steady gain and less background noise, the preconditioning of MCP stack including 380 ℃ bake-out for 18 h and 100 μA·h bake-in is done, background rate is measured before and after preconditioning, and the curve of MCP stack′s gain versus high voltage applied to MCP stack is obtained. Operating characteristics of the MCP detector including background rate, spatial resolution are also measured. The life-span of the detector is analyzed. The measured results show that the spatial resolution can reach 5.66 lp/mm, and background noise is less than 1 counts/(s·cm2), they can completely satisfy the requirement of moon-based EUV camera on the spatial resolution, background noise and life-span..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1104001 (2013)
Diffraction and Gratings
Transmission Bandpass Filters Based on Two-Dimensional Subwavelength Metallic Gratings
Zhou Wenchao, Wu Yihui, Hao Peng, Liu Guigen, and Li Kaiwei
In order to achieve the miniature and integration of the optical devices in multi-wavelength array detection, a novel transmission filter based on subwavelength metallic grating guided mode resonance is proposed. The resonance characteristics of the filters with symmetric and nonsymmetric waveguide structure are theoreIn order to achieve the miniature and integration of the optical devices in multi-wavelength array detection, a novel transmission filter based on subwavelength metallic grating guided mode resonance is proposed. The resonance characteristics of the filters with symmetric and nonsymmetric waveguide structure are theoretically analyzed. The effects of the grating structural parameters on the transmission spectrum are investigated in detail, such as filling factor, grating thickness, the sidewall angle, et al. And the optimal scope of the grating structure is also presented. Simulation results show that the peak position and the full width at half maximum (FWHM) of the filter are attributed to the grating period and the buffer layer. And the FWHM can be adjusted from 2 nm to 45 nm, the maximum transmittance increases to 81.7%. Besides, the transmission spectrum is independent on the polarization of the incident field due to the symmetry of the subwavelength metallic grating. The filters can satisfy the requirements of microfluidic and biosensing and so on..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1105001 (2013)
Fiber Optics and Optical Communications
Influence of Birefringence on Axial Strain Sensitivity of Birefringence Fiber Loop Mirror
Jiang Ying, Zeng Jie, Liang Dakai, Ni Xiaoyu, and Zhou Yabin
To investigate influence of birefringence on axial strain sensitivity of birefringence fiber loop mirror, change of axial strain sensitivity with birefringence is drawn by numerical simulation for the same strain dependent birefringence coefficient and different birefringences fibers. The simulation result shows that tTo investigate influence of birefringence on axial strain sensitivity of birefringence fiber loop mirror, change of axial strain sensitivity with birefringence is drawn by numerical simulation for the same strain dependent birefringence coefficient and different birefringences fibers. The simulation result shows that the axial sensitivity reduces with the increase of birefringence. The axial strain sensitivities of different birefringence fiber loop mirrors are compared by experiment. The curve of birefringence versus the axial strain sensitivity is fitted. The experimental fitting curve is in agreement with the simulation one. The result shows that the axial strain sensitivity can be improved by choosing a low birefringence fiber, but the birefringence can not be too low to measure axial strain because of generating weak interference spectrum..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1106001 (2013)
Design of Reflective All-Fiber Hydrogen Sensor
Zhou Feng, Qiu Sunjie, Luo Wei, Xu Fei, and Lu Yanqing
A new method by introducing a photonic crystal fiber (PCF) inline interferometer for hydrogen sensing is demonstrated. The sensing unit contains a piece of PCF, constituting a reflection-type hydrogen sensing system. One end and the outer face of the PCF are plated with a thin palladium film under vacuum conditions, whA new method by introducing a photonic crystal fiber (PCF) inline interferometer for hydrogen sensing is demonstrated. The sensing unit contains a piece of PCF, constituting a reflection-type hydrogen sensing system. One end and the outer face of the PCF are plated with a thin palladium film under vacuum conditions, while the other end connects to the optical path. Therefore, a set of all-fiber hydrogen sensor is accomplished. Hydrogen concentration from 0 to 5% is detected in the experiment and the related interferometric resonant wavelength shift is recorded. The maximum wavelength shift is over 1.2 nm. Compared with hydrogen sensors based on fiber Bragg grating, the sensitivity of the experiment has great improvement. The whole system not only has an all-fiber optical path without any bulk-optic components, but also owns a high sensitivity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1106003 (2013)
Polarization Mode Dispersion Monitoring Technique Based on Radio Frequency Power Spectrum
Huang Haili, Xi Lixia, Zhang Xiaoguang, Zhao Donghe, and Zhang Xia
Polarization mode dispersion (PMD) is a key technology in optical performance monitoring (OPM). A PMD monitoring method based on measuring the frequency of the minimum power of radio-frequency (RF) spectrum is proposed. By cascading a polarization maintaining optical fiber (PMF) with large differential group delay (DGDPolarization mode dispersion (PMD) is a key technology in optical performance monitoring (OPM). A PMD monitoring method based on measuring the frequency of the minimum power of radio-frequency (RF) spectrum is proposed. By cascading a polarization maintaining optical fiber (PMF) with large differential group delay (DGD) and a polarization controller (PC) at the receiver, the PMD can be monitored in low frequency of RF spectrum, and relevant theoretical analysis and numerical simulation are also proceeded. The results demonstrate that this method can monitor first order PMD precisely with low monitoring error in ±3 ps. In addition, it is insensitive to the optical signal-to-noise ratio (OSNR), chromatic dispersion (CD) and transmission rate. Varying the DGD in the PMF at the receiver, this method has different monitoring ranges and sensitivities..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1106004 (2013)
A Method for Evaluating the Disturbance in Distributed Vibration Sensor Based on Wavelet Information Entropy
Feng Xin, Zeng Zhoumo, Feng Hao, and An Yang
A processing algorithm combined with wavelet analysis and information entropy theory is proposed to settle the problem of average and difference methods′ not being effective enough to evaluate the vibration events in phase-sensitive optical time-domain reflectometer (OTDR) vibration sensing system. Based on a well-deveA processing algorithm combined with wavelet analysis and information entropy theory is proposed to settle the problem of average and difference methods′ not being effective enough to evaluate the vibration events in phase-sensitive optical time-domain reflectometer (OTDR) vibration sensing system. Based on a well-developed discussion on the features of acquired signal and wavelet information entropy method, the effect the length of window and step on processing result is revealed. Meanwhile, an adoption of weighting algorithm is proposed for further optimization. Experiments prove that this method performs well in distinguishing noise from disturbance, and can recognize exterior interference in a rapid, accurate way as well as pinpoint the interference location, which can enhance the performance of phase-sensitive OTDR system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1106005 (2013)
Geometric Optics
Effect of Polarization Aberration on the Image Quality of Schmidt Prism
Lu Jinjun, Yang Kai, Sun Xueping, Zhu Weibing, and Lü Hua
In order to analyze the effect of Schmidt prism′s polarization aberration on the imaging quality with the widely used un-polarized light, based on diffraction intensity distribution of polarized light vector and by using two incoherent superposition integral methods, the same diffraction patterns as un-polarized light In order to analyze the effect of Schmidt prism′s polarization aberration on the imaging quality with the widely used un-polarized light, based on diffraction intensity distribution of polarized light vector and by using two incoherent superposition integral methods, the same diffraction patterns as un-polarized light passing through the Schmidt prism are obtained. According to the equation of diffraction pattern, the polarization aberration consists of doubling of the image after the un-polarized passing through Schmidt prism and they are symmetrical. Analysis results of the central intensity ratio, resolution and the surface deformation defined in this paper show that the imaging quality of Schmidt prism is severely affected by the polarization aberration. B, one of the Jones matrix factors, as the structure characteristic of prism parameters, influences and determines the quality of imaging prism. The value of B indicates the size of polarization aberration of Schmidt prism. Both theoretical analysis and experimental results show that, the best condition for correction of Schmidt prism polarization aberration is B=0..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1108001 (2013)
Imaging Systems
Fast Lithography Simulation for One-Dimensional Layout
Xie Chunlei, Shi Zheng, and Lin Bin
One fast lithography simulation methodology is proposed for one-dimensional layout, taking advantage from the characteristics of partial coherent system and one-dimensional pattern. The new methodology consists of look-up table based on one-dimensional basis pattern, the minimum look-up table and its boundary extensionOne fast lithography simulation methodology is proposed for one-dimensional layout, taking advantage from the characteristics of partial coherent system and one-dimensional pattern. The new methodology consists of look-up table based on one-dimensional basis pattern, the minimum look-up table and its boundary extension, and simulation of large scale layout without division. Simulation and experiment results show that comparing the new algorithm with conventional method, the building time of look-up table is reduced by more than 95%, the simulation speed for basic pattern improves by about 48% and the simulation speed for large scale layout improves by more than 70% based on high accuracy..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1111001 (2013)
Influence of the Axial Component of Mask Diffraction Spectrum on Lithography Imaging
Dong Lisong, Li Yanqiu, and Guo Xuejia
Traditional three-dimensional (3D) vector imaging models treat the electric field distribution in the entrance pupil of projector by transforming the distribution in the local coordinate or ignoring the axial component of the mask diffraction spectrum (MDS). The accuracy of the model with the latter should be discussedTraditional three-dimensional (3D) vector imaging models treat the electric field distribution in the entrance pupil of projector by transforming the distribution in the local coordinate or ignoring the axial component of the mask diffraction spectrum (MDS). The accuracy of the model with the latter should be discussed in immersion lithography. The traditional 3D vector imaging model and a modified 3D lithography imaging model which integrates all the vector effects of plane wave through the whole imaging system are introduced. Then the influence of the axial component of MDS on the lithography imaging performance is analyzed by the modified imaging model and the resist model of commercial software PROLITHTM. The results are discussed by using frequency spectrum analysis. The simulation results show that the accuracy of traditional 3D vector imaging model is degraded in hyper numerical aperture (NA) system for the axial component of MDS on the entrance pupil of projector cannot be ignored any more in immersion lithography. This demonstrates that only the modified 3D imaging model under partially coherent illumination condition can satisfy the requirement of hyper NA lithography simulation..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1111002 (2013)
Instrumentation, Measurement and Metrology
Design of Stoilov Algorithm Grating Parameter Optimization Based on Statistical Approach
Xu Xingfen, and Cao Yiping
In the phase measuring profilometry (PMP) three-dimensional measurement based on Stoilov algorithm, the four abnormal phenomena lead to the incorrect phase calculation or incorrect phase unwrapping, so the measured object can′t be reconstructed well. The proposed method based on the statistical approach can restrain thIn the phase measuring profilometry (PMP) three-dimensional measurement based on Stoilov algorithm, the four abnormal phenomena lead to the incorrect phase calculation or incorrect phase unwrapping, so the measured object can′t be reconstructed well. The proposed method based on the statistical approach can restrain the abnormal phenomena availably and make up Stoilov algorithm defect. Meanwhile, it is found that Soilov algorithm is sensitive to the period and contrast of sinusoidal gratings. The pixel of phase imaging will be mutant and the measuring precision is to be influenced when the light intensity varies severely. Therefore, a method of grating parameter optimization based on the statistical approach Soilov algorithm is proposed. The measuring precision can be improved by optimizing the period and contrast of sinusoidal gratings under the experimental simulation. Experimental result shows its feasibility and validity..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1112001 (2013)
TMT M3 System Seismic Analysis Based on Time History Method
Su Yanqin, Wang Fuguo, Zhang Jingxu, and Chen Baogang
In order to complete the seismic analysis of thirty meter telescope (TMT) tertiary mirror cell assembly (M3CA), seismic wave fitting software has been developed, seismic time histories are obtained through the software, and then seismic analysis has been done based on time history analysis. The software fit for the seiIn order to complete the seismic analysis of thirty meter telescope (TMT) tertiary mirror cell assembly (M3CA), seismic wave fitting software has been developed, seismic time histories are obtained through the software, and then seismic analysis has been done based on time history analysis. The software fit for the seismic wave is developed based on the theory of trigonometric series with random phase, amplitude correction is introduced to increase the fitting precision, the average difference between fitting seismic wave spectrum and design response spectrum is less than 4%; then, according to the design response spectrum with average return period of 200 years, seismic time histories are fitted; finite element method (FEM) analysis is carried out based on time history analysis method. The simulation results illustrate that the displacement of tertiary mirror relative to the cell is 1.881 mm; the maximum stress on the mirror is 0.27 MPa which occurs on lateral supporting position; the maximum stress of the support system is 310.54 MPa and appears on the lateral support rod. Compared with material characteristics, the maximum stresses are all within material stress limitation, which indicates that the security will be assured when 200-year return period earthquake happens. The program obtains a high fitting precision and various factors are considered. Combined with the finite element analysis, it will provide experience for seismic analysis of large photoelectric equipment..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1112002 (2013)
Image-Matching-Based Temperature Field Measurement of Heat Dispersing Surface of Air-Cooled Condenser
Chen Lulu, Li Xiaolu, He Tao, and Xu Lijun
Measurement of the temperature field of heat dispersing surface of air-cooled condenser (ACC) is the basis of researching its heat transfer mechanism and characteristics. An image-matching-based temperature field measuring method is presented. Four infrared thermal imagers are used to photograph the longitudinal range,Measurement of the temperature field of heat dispersing surface of air-cooled condenser (ACC) is the basis of researching its heat transfer mechanism and characteristics. An image-matching-based temperature field measuring method is presented. Four infrared thermal imagers are used to photograph the longitudinal range, while the horizontal range is photographed by moving cleaning stand. 124 infrared images with overlay area are photographed. Geometric distortion correction is applied to the infrared images, and irradiance imbalance is removed. Characterized by centers of base tubes, the phase correlation algorithm based on gray projection is used for registration. Entire registered image is obtained with registration error less than 1 pixel. Then, based on the average grayscale of limited numbers of rows or columns in joint seams, the registered image is smoothed. Continuous temperature field image of the overall heat dispersing surface can finally be obtained with the maximum spatial resolution four times higher than that of a single image. Each pixel represents 12 mm on the surface, and a temperature measurement accuracy of ±0.4 ℃ is achieved. Comprehensive and accurate temperature distribution information of ACC can be provided by this method for the operation optimization of air-cooling units..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1112003 (2013)
Temperature Measurement on High Speed Sliding Electrical Contact Based on Principle of Infrared Radiation
Zhang Yuyan, Wang Wei, Wang Zhenchun, Wen Yintang, and Zhan Zaiji
In the process of high speed sliding electrical contact, the contact surface will produce electric phenomenon such as joule heat, arc, etc., that will lead to contact temperature mutations. Temperature is one of the key factors of the materials′ conductivity and friction and wear. In order to measure the instant changeIn the process of high speed sliding electrical contact, the contact surface will produce electric phenomenon such as joule heat, arc, etc., that will lead to contact temperature mutations. Temperature is one of the key factors of the materials′ conductivity and friction and wear. In order to measure the instant changes in temperature of high speed sliding contact, a transient temperature measurement method is proposed. A measurement system is designed based on the principle of infrared radiation in view of the high voltage and large current environment. This system contains optical fiber temperature measuring probe, isolation module and high-speed data acquisition module. Calibration experiment is performed with blackbody furnace, and verification experiment on the performance of the system is performed in the high-speed sliding experimental machine. The results show that the system′s effective temperature range for non-contact measurement can be 600 ℃~2000 ℃, and it has high accuracy and short response time. It is suitable for transient high temperature measurement such as the special environment of high speed sliding electrical contact..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1112004 (2013)
Reliable Initial Guess Based on SURF Feature Matching in Digital Image Correlation
Zhang Huajun, Li Guihua, Liu Cheng, and Wang Dan
Since the digital image correlation (DIC) method based on the Newton-Raphson (N-R) method is sensitive to initial values, a reliable initial guess method which utilizes an image feature matching algorithm of speeded up robust features (SURF) is presented. The SURF algorithm can match the feature points of the images beSince the digital image correlation (DIC) method based on the Newton-Raphson (N-R) method is sensitive to initial values, a reliable initial guess method which utilizes an image feature matching algorithm of speeded up robust features (SURF) is presented. The SURF algorithm can match the feature points of the images before and after deformation, and get the coordinate positions. The deformation parameter of a point of interest is initially estimated from the affine transformation which corresponds to the subset region of matched feature points. By iterating and optimizing the estimated values, the displacement which makes the zero-mean normalized sum of squared difference (ZNSSD) minimized is obtained. In the experiment, both the presented method and scale-invariant feature transform (SIFT) algorithm are used in the deformation measurement of carp scales stretching. It is shown that the proposed initialization method is more sufficiently accurate and can enable the subsequent N-R method to converge quickly..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1112005 (2013)
Gloss Modification Model Design of SCE Measurement Based on D/8 Condition Color Spectrophotometer
Yuan Kun, Yan Huimin, Jin Shangzhong, Cen Songyuan, and Wang Jian
The geometric conditions of diffuse illumination, 8° observation, and specular light exclusion (SCE) are often employed to measure the surface color. The SCE condition is usually realized by setting light trap on the integrating sphere. Due to the size of the optical trap, different structures of the measurement iThe geometric conditions of diffuse illumination, 8° observation, and specular light exclusion (SCE) are often employed to measure the surface color. The SCE condition is usually realized by setting light trap on the integrating sphere. Due to the size of the optical trap, different structures of the measurement instrument will lead to inter-instrument disagreement among the measurement of sample with different gloss. The reason of inter-instrument disagreement caused by different measuring structures is analyzed in theory; a measuring structure is designed to measure the SCE and specular light inclusion (SCI) results simultaneously. The gloss value is calculated from the SCE and SCI results. A computing model is proposed to modify the SCE measuring result based on the gloss value, and experimental verification is also carried out. Experimental results show that the modified model effectively reduces inter-instrument disagreement caused by different measuring structures, and is very suitable for engineering applications..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1112006 (2013)
Subaperture Testing Technique of Aspheres Based on Counter-Rotating Phase Plates
Song Bing, Chen Shanyong, and Wang Guilin
Subaperture stitching interferometry in combination with null test can extend the lateral and vertical dynamic range of measurement, which is applicable to surface figure measurement for large aperture and high-departure aspheres. By employing a pair of counter-rotating Zernike phase plates as near-null optics, variablSubaperture stitching interferometry in combination with null test can extend the lateral and vertical dynamic range of measurement, which is applicable to surface figure measurement for large aperture and high-departure aspheres. By employing a pair of counter-rotating Zernike phase plates as near-null optics, variable aberration is generated to balance most of the aberration for subapertures at different locations on various aspheric surfaces. The residual aberration is hence reduced within the vertical dynamic measurement range of a standard interferometer. The subaperture aberration of two test aspheres is calculated to solve the phase function of the Zernike plates. Meanwhile, the four-step etching process and power carrier are introduced to double the efficiency of diffraction and isolate the disturbance orders of diffraction. Finally the flexibility of the near-null optics is well demonstrated by applying it to the convex hyperbolic secondary mirror of stratospheric observatory for the infrared astronomy (SOFIA) telescope and a concave asphere. All subaperture aberrations are successfully reduced by the near-null optics, which shows its good adaptability to surface shape..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1112007 (2013)
Lasers and Laser Optics
970 nm Hundred-Watt Level Diode Laser Source by Spectral Beam Combining with External Cavity Feedback
Zhang Jun, Peng Hangyu, Cao Junsheng, Wang Biao, Liu Yun, Qin Li, Fu Xihong, and Wang Lijun
Laser combining is the main way to develop the high power diode laser source. Traditional beam combining is used to increase the power but leads to a poor beam quality. Spectral beam combining with external cavity feedback improves the characteristics of the power and the beam quality by the way of combining diode laseLaser combining is the main way to develop the high power diode laser source. Traditional beam combining is used to increase the power but leads to a poor beam quality. Spectral beam combining with external cavity feedback improves the characteristics of the power and the beam quality by the way of combining diode laser oscillation with external optical system. By spectral beam combining with external cavity feedback based on a transmission grating, a diode laser source is developed with a continuous wave power of 140.6 W, a beam quality of 4.367 mm·mrad and a spectrum width of 36.60 nm. The whole spectrum is composed of 56 independent wavelength peaks, each one of which is only corresponding to one of the combining laser units, respectively. A feasible solution to obtain a good beam quality for high power diode laser source is demonstrated..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1114001 (2013)
Study on Optical and Thermophysical Properties of Aluminum under Nanosecond Laser Irradiation
Chang Hao, Jin Xing, and Chen Zhaoyang
In the process of laser ablation, the target′s absorption coefficient, thermal conductivity, density and surface reflectivity are dependent on its temperature. When the target surface temperature approaches the thermodynamic critical temperature Tc, the high-temperature part of the target transits from metal to nonmetaIn the process of laser ablation, the target′s absorption coefficient, thermal conductivity, density and surface reflectivity are dependent on its temperature. When the target surface temperature approaches the thermodynamic critical temperature Tc, the high-temperature part of the target transits from metal to nonmetal. The target is divided into two temperature regions (below and above 0.8Tc) and a model is built up to calculate the above physical parameters. The temporal and spatial distribution of temperature, absorption coefficient and thermal conductivity of Al target are obtained by a one-dimensional heat conduction equation. Ablation depth is calculated as a function of laser pulse energies. Numerical results are in good agreement with the experimental results, which validate the presented model..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1114002 (2013)
Machine Vision
Application of Adaptive Kalman Filter Algorithm in High Accuracy Star Spot Location
Liu Nannan, Xu Shuyan, Cao Xiaotao, and Wang Dong
Space survey camera image stabilization system demands high control accuracy and puts forward higher requirements on the guide star sensor. In order to improve the accuracy and bandwidth of guide star sensor, star spot location method combining prediction windowing and Kalman filter is presented. Using gyros to measureSpace survey camera image stabilization system demands high control accuracy and puts forward higher requirements on the guide star sensor. In order to improve the accuracy and bandwidth of guide star sensor, star spot location method combining prediction windowing and Kalman filter is presented. Using gyros to measure three-axis angular rate information, and establishing a prediction equation for the rough position of the star spot, the rough position of star spot is obtained. Windowing in a small neighborhood of the predicted spot on the CMOS detector can improve the operation speed. Using Kalman filter algorithm to correct the position of the star spot, the accurate position of star spot is finally obtained. Simulation results show that compared with traditional centroid method, image processing time per frame is reduced from 59 ms to 27 ms, and the standard deviation of star location result is reduced from 0.1 pixel to 0.04 pixel. The proposed method is an effective way to improve the speed and accuracy of the star spot location, providing certain value for the development of China′s space survey camera..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1115001 (2013)
Deep Space Exploration Panoramic Camera Calibration Technique Based on Circular Markers
Wu Fanlu, Liu Jianjun, Ren Xin, and Li Chunlai
Considering the difficulties in construction and on-site processing of outdoor three-dementional calibration target, and the low precision of chessboard target, a new camera calibration method based on circular markers is put forward to meet the high-precision of panoramic camera for deep space explorations. A large nuConsidering the difficulties in construction and on-site processing of outdoor three-dementional calibration target, and the low precision of chessboard target, a new camera calibration method based on circular markers is put forward to meet the high-precision of panoramic camera for deep space explorations. A large number of circular markers are distributed on the target in matrix form, one of which is taken as the origin of world coordinate system. Based on the camera model and collinearity of object point, camera origin, and image point, the optimal camera parameters are obtained with nonlinear optimization method, which use minimizing projection error as objective function. Experimental results show that this method with higher precision and better robustness is feasible and effective. The accuracy is better than 0.3 pixel. The distortion model is suitable and the projection error is better than 0.07 pixel..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1115002 (2013)
Unified Rotation-Based Self-Calibration Method for Cameras
Li Baoquan, Fang Yongchun, and Zhang Xuebo
A unified rotation-based self-calibration strategy, which can be applied to both central catadioptric cameras and pin-hole cameras, is proposed for camera intrinsic parameter self-calibration. The two types of cameras are described by a unified spherical projection model. It is proved that when the camera frame makes pA unified rotation-based self-calibration strategy, which can be applied to both central catadioptric cameras and pin-hole cameras, is proposed for camera intrinsic parameter self-calibration. The two types of cameras are described by a unified spherical projection model. It is proved that when the camera frame makes pure rotation, the distance between spherical projection points for any two static feature points remains unchanged, based on which, a set of constraint equations with respect to camera intrinsic parameters are designed. An optimization function is constructed and finally solved by numerical algorithms. Compared with existing methods, the proposed calibration scheme can be applied to both central catadioptric cameras and pin-hole cameras, and it does not need any complex matrix computation. Simulation and experimental results show that the proposed strategy presents such merits as good robustness regarding image noise and undesired small translation, easy implementation, and sufficiently high calibration precision..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1115003 (2013)
Two Parallel Planes Calibration for Two-Dimensional Object Vision Measurement
Liu Chang
A camera calibration method based on two calibration planes model is studied for the monocular vision measurement of planar object. It uses polynomials to describe the correspondence between the measurement plane coordinates and the image coordinates. The polynomial coefficients, which can be estimated by least square A camera calibration method based on two calibration planes model is studied for the monocular vision measurement of planar object. It uses polynomials to describe the correspondence between the measurement plane coordinates and the image coordinates. The polynomial coefficients, which can be estimated by least square method, implicitly include the camera parameters and distortion parameters. A dark area problem caused by polynomial expression of the correspondence between the two planes is studied. An image coordinates translation method is proposed to solve the problem. Considering the calibration board′s thickness, the board is put on two locations which are parallel to the measurement plane with different heights, and the relationship between the two calibration planes and the image plane is calibrated respectively. Given the perpendicular distances among the measurement plane and the two calibration planes, the real object size can be computed from perspective projection principle. The experimental results verify the effectiveness of the method..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1115004 (2013)
Materials
Field Distribution of Polarized Light of Defect Mode in One-Dimensional Doping Photonic Crystal
Liu Qineng
Using the boundary conditions of TM wave, the light field of TM wave in one-dimensional (1D) doping photonic crystal is deduced, and the light fields of defect modes of TE wave and TM wave in 1D doping photonic crystal are studied. The light fields of defect modes of TE wave and TM wave exhibit the characteristic of reUsing the boundary conditions of TM wave, the light field of TM wave in one-dimensional (1D) doping photonic crystal is deduced, and the light fields of defect modes of TE wave and TM wave in 1D doping photonic crystal are studied. The light fields of defect modes of TE wave and TM wave exhibit the characteristic of resonance in impurity layer, and the light fields decrease with the increase of the optical thickness in band gap..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1116001 (2013)
A New Self-Activated Laser Crystal Material
Ning Kaijie, Zhang Qingli, Chen Jiakang, Dou Renqin, Wang Xiaofei, Sun Dunlu, and Yin Shaotang
A new self-activated NdTaO4 (NTO) crystal with the size of 30 mm×60 mm is grown by Czochralski method, and its crystal structure is investigated by the Rietveld full-profile fitting method. The grown NTO crystal shows the monoclinic system, space group I2/a, and lattice constants and density are also given. The rA new self-activated NdTaO4 (NTO) crystal with the size of 30 mm×60 mm is grown by Czochralski method, and its crystal structure is investigated by the Rietveld full-profile fitting method. The grown NTO crystal shows the monoclinic system, space group I2/a, and lattice constants and density are also given. The room temperature absorption and emission spectra of NTO crystal are studied. The strong broadband absorption peaks at 808.5 nm and 885 nm and the obvious broadband emission at 1063.5 nm are suitable for the laser diode (LD) pumped tunable laser or ultrashort laser. The NTO crystal can be used as a high gain self-activated microchip laser medium..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1116002 (2013)
Theoretical Study of the Structural, Stability and Spectral Properties of Ca2Sin(n=1~9) Clusters
Zhang Shuai, Zhang Yingying, Zhang Ping, Li Genquan, Lü Linxia, and Lu Cheng
The geometries, stabilities, and spectral properties of Ca2Sin(n=1~9) clusters are systematically investigated by using first principles calculations based on the hybrid density functional theory at the B3LYP / 6-311G (d) level. The optimized geometries indicate that the most stable structures of Ca2Sin clusters are thThe geometries, stabilities, and spectral properties of Ca2Sin(n=1~9) clusters are systematically investigated by using first principles calculations based on the hybrid density functional theory at the B3LYP / 6-311G (d) level. The optimized geometries indicate that the most stable structures of Ca2Sin clusters are three-dimensional structures for n=3~9. On the basis of the obtained lowest-energy geometries, the size dependence of cluster properties, such as averaged binding energies, second-order energy differences, fragmentation energies, HOMO-LUMO gaps and spectral properties, are discussed. The calculated results show that the impurity Ca atoms in the Ca2Sin clusters enhance the chemical stability of the silicon framework. The magic clusters are found at n=5, 7 and 9. In addition, the spectral analysis indicates, the number of the infrared (IR) absorption peaks of Ca2Si5 and Ca2Si9 is more, but Ca2Si7 is less. The Raman absorption peak of Ca2Si5 is only one and appears in the low frequency band, on the contray, Ca2Si7 and Ca2Si9 have more Raman absorption peaks..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1116003 (2013)
Ultra-Violet Transmission and Structure of Lithium Aluminum Silicate-Phosphate Glasses
Cui Qiaoqiao, Ding Mingye, Ni Yaru, and Lu Chunhua
Silica glasses are often used as the window material of ultra-violet (UV) detector due to having a high UV transmittance. However, this glass is not allowed to connect with other materials directly for its lower thermal expansion coefficient, otherwise, the innerstress can damage the materials. Therefore, using SiO2, PSilica glasses are often used as the window material of ultra-violet (UV) detector due to having a high UV transmittance. However, this glass is not allowed to connect with other materials directly for its lower thermal expansion coefficient, otherwise, the innerstress can damage the materials. Therefore, using SiO2, P2O5, Al2O3, Li2O as the components, the optical glasses with the high UV transmittance (the maximum up to 56% at 200 nm wavelength), high thermal expansion coefficient and good stability is prepared. The local structure of glasses is studied by magic angle spinning nuclear magnetic resonance (MAS-NMR) and Fourier transform infrared spectroscopy (FTIR). The results show that Si atoms in the glasses are located in the 4-coordinated states and phosphate groups are similar with ultraphosphate groups Q3 originally. And with the Al2O3 content increased, there is a non-bridge oxygen (P-O…Li). At the same time, the average of Al coordination number gradually reduces. The formation of Si-O-P, Si-O-Al and P-O-Al bridge oxygens indicates that the cross-linking among the three components is caused to form a three-dimensional network structure. Moreover, the UV transmittance can be improved when increasing Si-O-Si bonds and decreasing Si-O-P bonds..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1116004 (2013)
Research and Design of L3 Square Air Holes Photonic Crystal Cavity
Han Lihong, Liu Liming, Guo Xuan, Yu Zhongyuan, Lin Benlong, Zhao Huijie, Liu Xi, Liu Yumin, and Lu Pengfei
According to the research of rectangular photonic crystal slab, an L3 square air holes photonic crystal cavity is proposed. The Q factors, mode volumes, and resonant frequencies of L3 square air holes photonic crystal cavities with different side lengths are discussed using finite difference time domain (FDTD) method. According to the research of rectangular photonic crystal slab, an L3 square air holes photonic crystal cavity is proposed. The Q factors, mode volumes, and resonant frequencies of L3 square air holes photonic crystal cavities with different side lengths are discussed using finite difference time domain (FDTD) method. Based on the results, an L3 square air holes photonic crystal cavity is proposed and a fairly high Q value of 27719 is obtained, with the mode volume of 0.4361(λ/n)3 and the resonant wavelength at 1543 nm. The Purcell factor of the L3 square air holes photonic crystal cavity is as high as 4767..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1116005 (2013)
Medical Optics and Biotechnology
Noninvasive Blood Glucose Sensing with Near-Infrared Spectroscopy Based on Interstitial Fluid
Wu Chunyang, Lu Qipeng, Ding Haiquan, and Gao Hongzhi
A new near-infrared noninvasive method of detecting the glucose from human skin tissue interstitial fluid is presented. The skin tissue structure is refined, and the papillary layer containing a small amount of blood separated from the lower area of the dermal layer and the surface layer are used as the main objects. TA new near-infrared noninvasive method of detecting the glucose from human skin tissue interstitial fluid is presented. The skin tissue structure is refined, and the papillary layer containing a small amount of blood separated from the lower area of the dermal layer and the surface layer are used as the main objects. The wrist curved side is selected as the detecting part. And the average probe depth, the main absorption position, the average photon path length, the outputting energy and the fraction of absorbed energy in each skin tissue layer are calculated by the Monte Carlo method based on the above. The results show that both the average probe depth and the main absorption area are located in the papillary layer. The average photon path length is long enough and less energy is absorbed by the stratum corneum and the dermis when the distance between detector and the source is 0.6 mm. Thus the optimum source-detector distance of 0.6 mm is determined and the optical fiber detector is designed. The uniqueness of the method is that the spectral information from the epidermis and papillary is captured without the interference from the rich blood containing lower dermis, which is good for the near-infrared noninvasive blood glucose detection and provides a theoretical basis for the follow-up work..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1117001 (2013)
Nonlinear Optics
Study on Weak Light Nonlinearities Improvement Based on Transmitted-Type Electromagnetically Induced Grating
Su Xuefeng, Zhuo Zhongchang, and Zhang Hanzhuang
A scheme is proposed to form a transmitted-type electromagnetically induced grating and enhance cross-phase modulation (XPM) and self-phase modulation (SPM) of a probe pulse field using a standing-wave field in a four-level system. The shorter the probe pulse is, the higher intensities of standing-wave field and probe A scheme is proposed to form a transmitted-type electromagnetically induced grating and enhance cross-phase modulation (XPM) and self-phase modulation (SPM) of a probe pulse field using a standing-wave field in a four-level system. The shorter the probe pulse is, the higher intensities of standing-wave field and probe pulse field required to achieve the same phase shifts of XPM and SPM nonlinearities are, comparing with a long pulse or continuous wave (CW). Because of standing-wave grating generated by counter propagating resonant coupling fields, the resonant probe field can be transparent in the coherence medium with a giant nonlinear refractive index when an additional off-resonant coupling field is added. Group velocity of the probe pulse can be controllable by both XPM and SPM nonlinearities..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1119001 (2013)
Optical Design and Fabrication
Optical Design of Harmonic Diffractive Infrared Dual-Band and Dual-Field System
Li Yan, Zhang Bao, Hong Yongfeng, and Zhao Chunlei
On the basis of harmonic diffractive element theory and zoom theory, a dual-band and dual-field infrared optical system employing harmonic diffractive element is designed. The optical configuration is based on the axial motion of a lens group along the optical axis for changing field of view. The image quality evaluatiOn the basis of harmonic diffractive element theory and zoom theory, a dual-band and dual-field infrared optical system employing harmonic diffractive element is designed. The optical configuration is based on the axial motion of a lens group along the optical axis for changing field of view. The image quality evaluation are listed. Evaluation results show that the system has five lens and realizes a zoom of 40~80 mm in dual-band, which satisfing 100% cold shield efficiency. The modulaiton transform function value is over 0.5 at the Nyquist frequency for the waveband of 3.7~4.3 μm and over 0.3 at the Nyquist frequency for the waveband of 8.7~11 μm. The system is characterized by dual-band, high resolution, miniaturization and simple structure..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1122001 (2013)
Polarization Analysis of a Real High Numerical Aperture Optical LithographyLuo Hongmei
[in Chinese], [in Chinese], [in Chinese], [in Chinese], and [in Chinese]
Based on the polarization transmission theory in optical system, the polarization analysis of a real high numerical aperture (NA) refractive optical lithography system is made, where the anti-reflection coating within current technology, the absorption in coating and base, and polarized illumination are taken into accoBased on the polarization transmission theory in optical system, the polarization analysis of a real high numerical aperture (NA) refractive optical lithography system is made, where the anti-reflection coating within current technology, the absorption in coating and base, and polarized illumination are taken into account to obtain a higher-reliability result. Several polarization parameters at every optical interface are calculated, such as transmission, reflection, absorptance and diattenuation, to achieve the effects of anti-reflection coating, absorption of the materials and polarized illumination on transmission performance and imaging performance. The results reveal that the anti-reflection coating can dramatically enhance the performance and stability of this sample system, while reducing the effects of varied polarized illumination to a negligible degree. Besides, the dramatic absorption in the base material plays a main role in the intensity loss, and the absorption has a small contribution to overall polarization effects..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1122002 (2013)
Optimization Design of Rigid Endoscope with High Definition and Large Depth of Field
Yu Lu, Cheng Dewen, Zhou Wei, Wang Yongtian, Liu Xiaohua, and Jin Guofan
A rigid endoscope with high definition is designed. In order to ensure the effective field of view and normal transmission path in the limited lenses with diameters of 2.7 mm, the incident height and exit angle on the relay lens of feature rays are controlled during the optimization. As a result, an entrance pupil of 0A rigid endoscope with high definition is designed. In order to ensure the effective field of view and normal transmission path in the limited lenses with diameters of 2.7 mm, the incident height and exit angle on the relay lens of feature rays are controlled during the optimization. As a result, an entrance pupil of 0.3 mm is achieved, with a resolution of higher than 21 lp/mm and an angular resolution of 8.45 C/(°) in the object space. Stray light caused by total reflection on the inner wall of the rod lens is avoided at the same time. The modulation transfer function (MTF) reaches diffraction limit and the values of all fields are higher than 0.3 at 120 lp/mm. By taking consideration of large depth of field (DOF), a system with multiple object distance configurations is set up before the optimization. After optimization with an eyepiece added, the MTF values of all fields are 0.1 at 3 lp/mrad, close to the resolution limit of human eye. Test results show that the resolution of fabricated system reaches theoretical design values..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1122003 (2013)
Optical Devices
Effect of Adjusting Force on Surface Figure of Optical Element in Axial Adjustment Mechanism
Guo Kang, and Gong Yan
Axial adjustment mechanism is applied in deep ultraviolet photolithography objective lens for aberration compensation. Since the surface accuracy of the optical element in the objective lens is rigorous, effect of the adjusting force on the surface figure of optical element in the axial adjustment mechanism cannot be iAxial adjustment mechanism is applied in deep ultraviolet photolithography objective lens for aberration compensation. Since the surface accuracy of the optical element in the objective lens is rigorous, effect of the adjusting force on the surface figure of optical element in the axial adjustment mechanism cannot be ignored. Regularity between the adjusting force and the surface figure of the optical element is investigated aiming at an axial adjustment mechanism with monolithic configuration. Finite element method is adopted to analyze the relationship between the adjusting force and the root-mean-square (RMS) value, Code V standard Zernike coefficients for the surface figure evaluation of the optical element. Methods for reducing the effect of the adjusting force on the surface figure of optical element are further proposed, which is adjusting force isolation and adjusting force absorption. The calculation results show that the RMS value and the Zernike coefficients linearly change with the adjusting force, and the adjusting force does not cause the existing aberration to transform into other types of aberrations, nor lead to a new generation of aberration. After flexible structure is introduced and set between the optical element and the support mount of the axial adjustment mechanism, the variation amplitude of RMS value reduces from 187% to less than 8%, which indicates that the effect of the adjusting force on the surface figure of optical element is effectively controlled..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1123001 (2013)
Optimized Analysis of Diffraction Efficiency for Liquid Crystal Optical Phased Array
Zhao Xiangjie, Liu Cangli, Zhang Dayong, and Luo Yongquan
Diffraction efficiency and scanning range determine the optical performance of liquid crystal optical phased array. To enhance the scanning range, it is necessary to fabricate high spatial resolution device. But due to the limitation of the nonlinear correlation effect, there is a tradeoff between the diffraction efficDiffraction efficiency and scanning range determine the optical performance of liquid crystal optical phased array. To enhance the scanning range, it is necessary to fabricate high spatial resolution device. But due to the limitation of the nonlinear correlation effect, there is a tradeoff between the diffraction efficiency and the scanning range. The key parameters influencing the diffraction efficiency of optical phased array are elucidated based on the mechanism of nonlinear correlation. The effect of the material parameters and device structural parameters on the diffraction efficiency is also investigated, and suggestion is given to enhance the diffraction efficiency. Furthermore, to reduce the effect of nonlinear correlation, optimization method is employed to adapt the voltages applied on each electrode to enhance the diffraction efficiency and proved to be in effect, which will contribute to enlarge the scanning range of optical phased array..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1123002 (2013)
Narrow-Band Filter of Surface Plasmon Based on Dual-Section Metal-Insulator-Metal Structure
Luo Xin, Zou Xihua, Wen Kunhua, Pan Wei, Yan Lianshan, and Li Xiaofeng
A narrow-band plasmonic filter based on dual-section metal-insulator-metal (MIM) structure is proposed, which consists of two metal layers and two insulator layer sections separated by a metal film. Each layer section contains four insulator periodic units structured by alternately stacking two insulators with differenA narrow-band plasmonic filter based on dual-section metal-insulator-metal (MIM) structure is proposed, which consists of two metal layers and two insulator layer sections separated by a metal film. Each layer section contains four insulator periodic units structured by alternately stacking two insulators with different refractive indices. In the filter, both long range surface plasmons (LRSPs) and short range surface plasmons (SRSPs) at different resonant wavelengths are stimulated under the condition of light injection. Some transmission peaks are formed at a specific wavelength where the resonance condition for the LRSPs or SRSPs is satisfied. The insertion of a metal film into the two insulator layer sections enables us to increase the coupling distance of both ends of the metal film and to reduce the 3 dB bandwidth of transmission peak. At the same time, the resonance wavelength of LRSPs (SRSPs) will be blue-shifted (red-shifted), so that the transmission peaks of LRSPs and SRSPs overlap at a specific wavelength, resulting in the generation of a narrow-band transmission peak with high peak-to-notch contrast ratio. The transmission characteristics of the proposed filter are numerically investigated by using the finite-difference time-domain (FDTD) method. A transmission peak with a 3 dB bandwidth of 9.2 nm and a peak-to-notch contrast ratio about 37.2 dB is confirmed in the 1.3 μm range. By further increasing the width of metal film to 55 nm, the 3 dB bandwidth can be reduced to 7.2 nm and the peak-to-notch contrast ratio can be increased to 40.1 dB. Therefore, excellent narrow-band filtering performance is obtained..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1123003 (2013)
Filter Properties of Circular Cavity Embedded with Cross Metallic Structure
Pang Shaofang, Zhang Zhongyue, and Qu Shixian
A circular resonator embedded with the cross structure based on the metal-insulator-metal surface plasmon polaritons (SPPs) waveguide is designed. The filter properties of this composite resonator are numerically investigated by the finite-difference time-domain method. The results show that the rotated cross structureA circular resonator embedded with the cross structure based on the metal-insulator-metal surface plasmon polaritons (SPPs) waveguide is designed. The filter properties of this composite resonator are numerically investigated by the finite-difference time-domain method. The results show that the rotated cross structure destroys the symmetry of the resonant mode of SPPs in the empty circular cavity, which results in novel filter function of the complex resonator. The filter function of a circular resonator embedded with the cross structure depends on the rotating angle of the cross structure. Compared to θ=0° case, when the cross structure rotate to a certain angle, there is only one transmission peak in the transmission spectra. In addition, the filter properties of the composite resonator are strongly dependent on the cross structure size. These results will be helpful for designing composite filters with specific usage..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1123004 (2013)
Physical Optics
Vectorial Structure Characteristics of Two Edge Dislocations in Gaussian Beams in Far Field
Tang Bihua, Luo Yamei, Xu Biao, and Zhu Yuan
Based on the methods of vector angular spectrum and stationary phase, the analytical expressions of the transverse electric (TE) and transverse magnetic (TM) terms and energy flux distributions of two edge dislocations in Gaussian beams in the far field are derived and used to analyze the phase singularities and energyBased on the methods of vector angular spectrum and stationary phase, the analytical expressions of the transverse electric (TE) and transverse magnetic (TM) terms and energy flux distributions of two edge dislocations in Gaussian beams in the far field are derived and used to analyze the phase singularities and energy flux distributions. The result shows that two edge dislocations appear in the electric field component on condition that two off-axis distances are equal to zero. The edge dislocations will vanish and optical vortices may take place when two off-axis distances are nonzero. Edge dislocations and optical vortices and energy flux distributions are symmetric about the origin. With increasing the off-axis distances, optical vortices and black nuclei in the energy flux distributions move toward the origin and coincide at the origin..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1126001 (2013)
Steering Asymmetric Spin Splitting in Photonic Spin Hall Effect by Orbital Angular Momentum
Zhang Jin, Luo Zhaoming, Luo Hailu, and Wen Shuangchun
Based on the angular spectrum theory of plane wave, the orbital angular momentum steer asymmetric splitting in photonic spin Hall effect (SHE) is studied. Taking the beam reflection at an air-glass interface for example, a propagation model describing the SHE of vortex beam is established, which clearly shows that the Based on the angular spectrum theory of plane wave, the orbital angular momentum steer asymmetric splitting in photonic spin Hall effect (SHE) is studied. Taking the beam reflection at an air-glass interface for example, a propagation model describing the SHE of vortex beam is established, which clearly shows that the transverse displacements of left-handed and right-handed circular polarization components are asymmetric with regard to the incident plane. Particularly, the displacement magnitudes and directions of the two spin components are significantly affected by the topological charge of vortex beam. The asymmetric splitting is steered by orbital angular momentum which can be regarded as integral transverse shifts of two spin components for the incident plane. The integral transverse shifts correspond to Imbert-Fedorov effects of linear polarization vortex beam. The physics nature of these phenomenon are attributable to the spin-orbit interaction and orbit-orbit conversion at the interface, and this is little different from its symmetric counterpart for Gauss beams. The results suggest that the orbital angular momentum of light provides an alternative degree of freedom for tuning the photonic SHE..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1126002 (2013)
Quantum Optics
Quantum Correlation Dynamics and Transfer Based on Weak Measurement
Du Shaojiang, Xia Yunjie, Man Zhongxiao, Zhang Yingjie, and Duan Deyang
Dynamics evolution of quantum correlation of two entangled qubits is investigated by using the techniques of weak measurement. The initial non-maximally entangled particles with entanglement sudden death happening are operated by pre-selection measurement, which not only improve the quantum correlations, but also can rDynamics evolution of quantum correlation of two entangled qubits is investigated by using the techniques of weak measurement. The initial non-maximally entangled particles with entanglement sudden death happening are operated by pre-selection measurement, which not only improve the quantum correlations, but also can reduce or even eliminate entanglement sudden death region; As for the evolution of non-maximally entangled initial state without entanglement sudden death, the weak measurement will degrade the intensity of quantum correlation of qubits. The operation of weak measurement can not enhance entanglement between particles but can optimize quantum discord when particles are initially in maximally entangled state. Weak measurement has little effect on the quantum correlation transfer procession and can postpone the decay of entanglement, and even can make entanglement transfer happen earlier. In addition, the relation of system dissipation rate and coupling strength between the cavity field and qubits can also affect its dynamical evolution, showing Markov and non-Markov processes..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1127001 (2013)
Remote Sensing and Sensors
Improved Dimensionality Reduction Algorithm of Large-Scale Hyperspectral Scenes Using Manifold
Zhang Jingjing, Zhou Xiaoyong, and Liu Qi
It is practicable for dimensionality reduction of hyperspectral scenes using manifold algorithm such as isometric mapping (ISOMAP) and local linear embedding (LLE). However the two classical manifold algorithm are not suitable for solving the large-scale hyperspectral scenes. We elaborate the problems encountered in apIt is practicable for dimensionality reduction of hyperspectral scenes using manifold algorithm such as isometric mapping (ISOMAP) and local linear embedding (LLE). However the two classical manifold algorithm are not suitable for solving the large-scale hyperspectral scenes. We elaborate the problems encountered in applying ISOMAP and LLE to dimensionality reduction of large-scale hyperspectral scenes, then an improved algorithm called IISOMAP-LLE, which is based on incremental isometric mapping (IISOMAP) and LLE, is proposed to represent the nonlinear structure of hyperspectral imagery that linear algorithm minimum noise fraction (MNF) could not discover. At last we demonstrate two experiments using large-scale AVIRIS and OMIS-II hyperspectral scenes to illustrate the approach. Experimental results prove that the IISOMAP-LLE not only is much better than linear algorithm MNF but also can avoid superiority decline of separability compared with MNF that encounterd in enhanced isometric mapping..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1128001 (2013)
Scattering
Intensity Distribution of Polarized Light Scattering for a Nucleated Cell
Ding Chizhu, Yang Kecheng, Li Wei, and Xia Min
A model is established as a spheroid with a concentric spherical core according to the morphology and size of marine microbes. The calculation of cells with different sizes and morphologies are implemented using the discrete dipole approximation (DDA) method. With the resulting Mueller matrices, the distributions of poA model is established as a spheroid with a concentric spherical core according to the morphology and size of marine microbes. The calculation of cells with different sizes and morphologies are implemented using the discrete dipole approximation (DDA) method. With the resulting Mueller matrices, the distributions of polarized light scattering intensity are analyzed. The results show that the polarized light scattering characteristics are sensitive to the orientation, shape, size and size of the nucleated cell. The study on polarized light scattering can be used in classification and research of marine microbes and other cells..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1129001 (2013)
Spectroscopy
Infrared Background Compression Method Based on Brightness Temperature Spectrum
Cui Fangxiao, and Fang Yonghua
Most pollutant gases have obvious absorbing or emitting features in the infrared band. Passive Fourier transform infrared (FTIR) remote sensing technology is used to detect and identify pollutant gases in a standoff distance. In the case of remote sensing pollutant gases on the mobile platform, the background is unknowMost pollutant gases have obvious absorbing or emitting features in the infrared band. Passive Fourier transform infrared (FTIR) remote sensing technology is used to detect and identify pollutant gases in a standoff distance. In the case of remote sensing pollutant gases on the mobile platform, the background is unknown and the spectrum includes interferents′ spectral features such as atmospheric gases, thus background compression method is needed to extract target spectral features. An infrared background compression method based on brightness temperature spectrum is proposed, in which the background radiance is referred as a slowly-varied baseline. The radiance transmitting simulation software named MODTRAN is used to simulate interferents′ spectral features such as atmospheric gases, and the infrared background compression is realized based on least-square fitting principle. The experiment takes ammonia as the target gas and the low altitude sky as the background. The results indicate that this method can effectively compress the background and interferents′ features, extract the ammonia′s spectral features and calculate the concentration-path-length..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1130001 (2013)
Research on the Effect of Light Intensity Modulation on the Line Shape of the Second Harmonic in the Wavelength Modulation Technology
Hu Yajun, Zhao Xuehong, Zhang Rui, Guo Yuan, and Wang Yan
Since the light intensity is modulated in the wavelength modulation spectroscopy (WMS) in the trace gas detection based on tunable diode laser absorption spectroscopy (TDLAS), the output signal can be accompanied by the residual amplitude modulation (RAM), which can affect the line shape of the detection signal and theSince the light intensity is modulated in the wavelength modulation spectroscopy (WMS) in the trace gas detection based on tunable diode laser absorption spectroscopy (TDLAS), the output signal can be accompanied by the residual amplitude modulation (RAM), which can affect the line shape of the detection signal and the noise to a certain extent. Theoretical model and analysis of the second harmonic signal of arbitrary large modulation amplitude based on Fourier analysis are presented, and the theoretical explanations about the distortion of the absorption lines are given. The effect of linear intensity modulation and non-linear modulation on the spectral distortion is analyzed, and the basic reasons of the asymmetry of the second harmonic and the noise are given. Considering the intensity amplitude modulation, the experiment of the the second harmonic detection of NH3 based on the TDLAS is conducted and the effect of the modulation amplitude on the distortion of absorption lines is evaluated. The experimental results confirm the theoretical analysis..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1130002 (2013)
A New Reduction Technique for Thermospheric Wind and Temperature Measurement with Fabry-Perot Interferometer
Wang Hong, Liu Xuebin, Feng Yutao, and Bai Qinglan
The principle of measuring thermospheric wind and temperature by Fabry-Perot interferometer (FPI) is elaborated, the transfer function of FPI and the analytical response expression to the incident line is studied. Referring to the basic principle of traditional wind and temperature retrieval method with FPI, a new matrThe principle of measuring thermospheric wind and temperature by Fabry-Perot interferometer (FPI) is elaborated, the transfer function of FPI and the analytical response expression to the incident line is studied. Referring to the basic principle of traditional wind and temperature retrieval method with FPI, a new matrix reduction technique is proposed. This technique is based on the decompose and approximate mathematics to obtain the matrix form of analytical response expression, then a least-squares technique is employed to get the thermospheric wind and temperature. Simulation results show that when the guessed wind is less than 150 m/s and the guessed temperature is less than 80 K, the error range is ±3 m/s for wind and ±10 K for temperature. The matrix technique not only retains the accuracy of a full Fourier Series Representation method, but also avoids instrument calibration and wavelength translation, which makes it simple and fast..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1130003 (2013)
Thin Films
Design and Preparation of Ultraviolet Signal Acquisition Filter Film in Optical Warning System
Kou Yang, Fu Xiuhua, Liu Feng′e, Liu Dongmei, and Tang Haolong
According to the requirement of ultraviolet (UV) warning system, based on the structure of Fabry-Perot (F-P) narrowband filter, by analysing film systems theory, the research of material evaporation process, adjustment and optimization of the ion source parameters, using the combination of different film system design,According to the requirement of ultraviolet (UV) warning system, based on the structure of Fabry-Perot (F-P) narrowband filter, by analysing film systems theory, the research of material evaporation process, adjustment and optimization of the ion source parameters, using the combination of different film system design, the UV filter film which can collect the UV signal effectively is designed and prepared. The peak transmittance of this film in UV is 17.96%, half-peak bandwidth is 20 nm. The filter can collect the UV signal more accurate and ultraviolet and visible band are inhibited effectively, so the background noise can be controlled at a low level. The cut-off degree is less than -30 dB. This film can filter natural light and collect the UV signal effectively in the UV warning system, and it has a significant contribution to improve the overall accuracy of the system..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1131001 (2013)
Influence of Sample Thickness on the Magnetic-Field-Induced Birefringence of the Nanostructured Magnetic Fluids
Wang Ning, Pu Shengli, and Wang Haotian
The influence of sample thickness of different concentration magnetic fluid on the magnetic-field-induced birefringence is studied. Experimental results show that the birefringence of magnetic fluid sample decreases with the thickness of magnetic fluid with certain concentration. The variation of birefringence with theThe influence of sample thickness of different concentration magnetic fluid on the magnetic-field-induced birefringence is studied. Experimental results show that the birefringence of magnetic fluid sample decreases with the thickness of magnetic fluid with certain concentration. The variation of birefringence with the externally magnetic field strength is different for samples with different thicknesses. For the thin sample, its birefringence increases gradually with the magnetic field and then saturates at relatively high magnetic field. For the thick sample, the birefringence varies non-monotonously or oscillates with the externally magnetic field. The magnetic fluid concentration has obvious influence on the thickness-dependence of the birefringence. The higher the concentration, the smaller the thickness of the sample for the occurrence of non-monotonous or oscillating variation of birefringence with magnetic field. The underlying physical mechanisms are clarified. The transition magnetic field is defined and employed to analyze the corresponding phenomena quantitatively..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1131002 (2013)
X-Ray Optics
X-Ray Spectrum Estimation Method from Scanning Data of Computed Tomography Phantoms
Zhang Huitao, and Zhang Peng
X-ray spectrum plays an important role in dual spectral X-ray computed tomography (CT) imaging, CT beam hardening correction, quantitative CT analysis and so on. The conventional methods estimate the spectrum from a set of transmission data measured directly for different thicknesses of step-wedge phantoms. A novel estX-ray spectrum plays an important role in dual spectral X-ray computed tomography (CT) imaging, CT beam hardening correction, quantitative CT analysis and so on. The conventional methods estimate the spectrum from a set of transmission data measured directly for different thicknesses of step-wedge phantoms. A novel estimation method of X-ray spectrum is proposed. The proposed method has two features. First, the dependence of the transmission intensity on the thickness of attenuation materials from the CT data of simple phantoms is restored. This not only simplifies the phantom production and the measurement process, but also can restore a more accurate dependence of the transmission intensity on the thickness of materials. Second, an alternative iteration algorithm for the spectrum estimation based on the parameter spectrum model is developed, in which the effect of the anode material is considered. The algorithm can relieve ill-posedness and instability for solving the spectrum estimation problem, by using the parameter X-ray spectrum model as constraint condition. The results of numerical experiments with several simulation data suggest that the proposed method is capable to reconstruct X-ray spectra more accurately and robustly for both bremsstrahlung and characteristic photons, compared with some transmission measurement methods..
Acta Optica Sinica
- Publication Date: Jan. 01, 1900
- Vol. 33, Issue 11, 1134001 (2013)
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