Journals >Acta Photonica Sinica
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2010
Volume: 39 Issue 12
34 Article(s)
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Research Article
Thermal Characteristic of VCSEL with AlN Film Passivation Layer
MA Xiang-zhu, ZHANG Si-yu, ZHAO Bo, LI Hui, HUO Jin, and QU YI
In this paper, the internal thermal field and heat flow vector distributions of high power vertical-cavity surface-emitting semiconductor lasers (VCSELs), which is based on AlN film and SiO2 film passivation layers, were analyzed using ANSYS finite-element software. The simulation results proved that the AlN film passiIn this paper, the internal thermal field and heat flow vector distributions of high power vertical-cavity surface-emitting semiconductor lasers (VCSELs), which is based on AlN film and SiO2 film passivation layers, were analyzed using ANSYS finite-element software. The simulation results proved that the AlN film passivation layer has better features than the SiO2 film passivation layers, and can make the device work in a more stable status, which also improves the device characteristics. Through the simulation, it was found that the Rthjc of VCSEL in AlN film was 3.12 K/W and the Rthjc of VCSEL in SiO2 film was 4.77 K/W. Comparison with the experimental values that the AlN film of 3.59 K/W and the SiO2 film of 4.82 K/W shows that simulation results are in good agreement with the experimental results. The proposed research works prove that the AlN film passivation layer has better thermal features than SiO2 film passivation layer..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2113 (2010)
Effects on Two-Dimensional Electrophoresis Seperation of Panax Ginseng Proteins by Gradient Polyacrylamide Gels
SUN Li-wei, LEI Xiu-juan, MA Rui, CHEN Jia-qing, JIANG Rui, and ZHAO Da-qing
In order to promote the research and analysis of panax ginseng proteins through the high quality and resolution 2-DE maps of panax ginseng，a two dimensional electrophoresis technology by gradient polyacrylamide gels is presented. In this work, total sample proteins are firstly extracted from the ginseng root, and then In order to promote the research and analysis of panax ginseng proteins through the high quality and resolution 2-DE maps of panax ginseng，a two dimensional electrophoresis technology by gradient polyacrylamide gels is presented. In this work, total sample proteins are firstly extracted from the ginseng root, and then are seperated by IEF and 12.5% humogeneous polyacrylamide gel and 10%~12.5%, 12.5%~15%, 10%~15% gradient polyacrylamide gels. After all images are scaned and analyzed by Image Scanner and Image Master 2D Platinum version 6.0 system, the optional concentration of gradient polyacrylamide gel is obtained. A lot of low abundance protein spots and large molecular weight spots are observed in 10%~15% gradient polyacrylamide gel map, which indicate that the seperation efficiency of gradient gel is highly improved. The results establish the fundation of high quality 2-DE maps of panax ginseng, andprovide a tool for the proteomic analysis of other Araliaceae plants..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2118 (2010)
Monitoring Method for Brain Edema Based on Near-infrared Spectroscopy
LIU Xing, LI Wei-tao, QIAN Zhi-yu, and ZHANG Jian-hua
A noninvasive monitoring method for brain edema based on near infrared photoelectric detection technology is proposed. The measurement principles and system composition of the monitoring instrument are studied. The light source of the instrument is 760 nm and 850 nm dual-wavelength LED, which is driven by constant currA noninvasive monitoring method for brain edema based on near infrared photoelectric detection technology is proposed. The measurement principles and system composition of the monitoring instrument are studied. The light source of the instrument is 760 nm and 850 nm dual-wavelength LED, which is driven by constant current source module. The light signal, scattered from the tissue, is detected by OPT101. Then the signal is processed by phase-locked amplifier and filter circuit. The filtered data are sampled by data acquisition card and processed in the LabVIEW environment in computer. The proposed system can monitor the changes in the brain of hemoglobin on real time. The system is used to monitor the changes of light intensity and blood oxygen content of the model of brain edema in mouse. The relationship between the changes of light intensity and oxygen parameters and brain edema is studied. The experimental results show that the near infrared photoelectric detection technology can be used as the noninvasive monitoring method for brain edema..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2123 (2010)
A Method to Improve Spectral Resolution for the Static Fourier Interferometer
ZHAO Jun-qi, and LIU Zhi-chao
In order to improve spectrum resolution with the same size of the static Fourier transform interferometer, an orthogonal-wedge static Fourier transform interferometer is designed, which is made up by the two orthogonal-wedge for continuous optical path difference. According to the derivation of the optical path differeIn order to improve spectrum resolution with the same size of the static Fourier transform interferometer, an orthogonal-wedge static Fourier transform interferometer is designed, which is made up by the two orthogonal-wedge for continuous optical path difference. According to the derivation of the optical path difference function with the tradition static Fourier transform interferometer and the orthogonal-wedge static Fourier transform interferometer, the structure of the two orthogonal-wedge is designed to increase the effective distance of detection for improving spectrum resolution of static interferometer. The simulation results show that the maximum optical path difference of the orthogonal-wedge interferometer is 0.323 4 mm, which is four times better than the traditional interferometer with 0.080 8 mm (optical path difference). Experimental results show that the orthogonal-wedge interferometer has the distortion of the interference fringes as a result of its detection principle, so it needs to be removed and filtering of the edge of the interference fringes. Using the WQF520 type spectrometer to comparative experiment for 800nm laser, the orthogonal-wedge interferometer error is less than 1 nm. This method can effectively improve the spectral resolution of the static Fourier transform interferometer..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2129 (2010)
Determination of Cr and Ba in Soil Using Laser Induced Breakdown Spectroscopy with Artificial Neural Networks
SHEN Qin-mei, ZHOU Wei-dong, and LI Ke-xue
A laser-induced breakdown spectroscopy (LIBS) technique based on artificial neural networks (ANN) is proposed for high accuracy elemental quantitative analysis. A combination method of laser induced breakdown spectroscopy with an artificial neural networks is employed to predict the concentrations of Cr and Ba in soil A laser-induced breakdown spectroscopy (LIBS) technique based on artificial neural networks (ANN) is proposed for high accuracy elemental quantitative analysis. A combination method of laser induced breakdown spectroscopy with an artificial neural networks is employed to predict the concentrations of Cr and Ba in soil samples. A back-propagation algorithm with momentum coefficient and adaptive learning rate is used and served as a calibration strategy for LIBS. The quantitative results and relative standard deviation of repeated predictions are obtained. The results are compared with those obtained by conventional calibration curve methods. The results presented demonstrate that the combination method of LIBS with ANN performs better than conventional calibration curve methods in quantitative detection of Cr and Ba in soil with improved accuracy and measurement precision in terms of relative standard deviation. Furthermore, it is an excellent method for LIBS quantitative detection for heavy metal in soils..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2134 (2010)
Design of Multiple DOF Fine Tuning Mechanism for 45° Tilting Mirror
ZHANG Li-min, and WU Yuan-hao
Aiming at overcoming difficulties in requirements satisfaction of the tolerance by simple connecting the optical components with their mechanical supports in the acurate-fine optical system, which means it will cost extremely expectation to the accuracy of mechanical process and adjustments,a fine tuning supporting mecAiming at overcoming difficulties in requirements satisfaction of the tolerance by simple connecting the optical components with their mechanical supports in the acurate-fine optical system, which means it will cost extremely expectation to the accuracy of mechanical process and adjustments,a fine tuning supporting mechanism to the 45° tilting mirror which can split or deflect the beam in optical system is presented. By employing multiple DOF tuning mechanism, it can set the 2-D tilt and take displacements in the direction normal to beam path at the same time. Flexible element is designed to improve the adjusting accuracy to the magnitude of second. Dovetail groove rail displacement technique is considered to save the cost of fund and time in machining process, and its displacement rang is 0~10 mm. Detailed analysis and discussions are presented in the key part of the mechanism by finite element analysis software. The whole research technique can be a fine reference to the optic-mechanical system of the same kinds and has great application value in beam setting of optical system..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2139 (2010)
Novel Long Wavelength Infrared Diffractive/Refractive Athermal Optical System
GAO Hong-yun, CHEN Meng-wei, YANG Ying-ping, CHEN Che, and ZHENG Pan
To improve performance of a large area high resolution optical system, a novel infrared diffractive-refractive hybrid system in 8~12 μm with 16° FOV is designed based on the thermal properties of the diffractive lens and the theory of athermalization. The effective focal length and back working distance of the sysTo improve performance of a large area high resolution optical system, a novel infrared diffractive-refractive hybrid system in 8~12 μm with 16° FOV is designed based on the thermal properties of the diffractive lens and the theory of athermalization. The effective focal length and back working distance of the system are respectively 100 mm and 133 mm,while the F number is 1.9. The system is composed of three lenses, which used only two materials of Ge and ZnSe, including a conic surface and a diffractive surface.The results show that the hybrid system possesses better athermal performances and high image quality in －30 ℃~70 ℃.Additionally, the system has a compact structure, lightweight, which make the system can satisfy the necessary specifications of modern optical instruments..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2143 (2010)
Simultaneous Measurement of Multi-solute Concentrations in Mixed Solution Using Fiber Fabry-Perot Resonator Interference Transmission Wavelengths
JIN Qing-li, HUANG Xiao-hong, WANG Zhen-guo, YAN Li-fen, and ZHANG Dong
In order to simultaneously detect the multi-solute concentrations in mixed solution, system for measuring the multi-solute concentrations in mixed solution using optical Fiber Fabry-Perot Resonator(FFPR) is proposed. The relation between FFPR interference transmission wavelength and concentrations of the mixed solutionIn order to simultaneously detect the multi-solute concentrations in mixed solution, system for measuring the multi-solute concentrations in mixed solution using optical Fiber Fabry-Perot Resonator(FFPR) is proposed. The relation between FFPR interference transmission wavelength and concentrations of the mixed solution is analyzed theoretically. The measuring system consists of an InGaAs LED, fiber coupler, FFPR sensor, opto-electrical convertor, amplifier and spectrometer. The analytical equation between concentrations and interference transmission wavelengths is standardized by measuring the samples contain ethanol and glycerin. The action script 2.0 is used as the programming language according to the mathematical relation. The real-time variation of the concentration change is monitored by the PC..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2147 (2010)
Real Envelope Imaging Algorithm for Inverse Synthetic Aperture Imaging Lidar
ZANG Bo, GUO Rui, TANG Yu, and XING Meng-dao
Limited by laser modulation technology and the phase information that is easily damaged by atmospheric turbulence, it is difficult to obtain the 2-D high-resolution image using traditional coherent integration algorithms for Inverse Synthetic Aperture Imaging Lidar (ISAIL). To solve this problem, a real envelope imaginLimited by laser modulation technology and the phase information that is easily damaged by atmospheric turbulence, it is difficult to obtain the 2-D high-resolution image using traditional coherent integration algorithms for Inverse Synthetic Aperture Imaging Lidar (ISAIL). To solve this problem, a real envelope imaging algorithm was proposed based on inverse Radon transform. Using the proposed method, the ISAIL system can transmit noncoherent laser pulses and high-quality image can also be obtained under the condition of atmospheric turbulence with low pulse repetition frequency. The ISAIL imaging experiment with numerical data validates the feasibility and effectiveness of the proposed method..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2152 (2010)
Kirkpatrick-Baez Mirror Imaging Simulation and Comparison with Fresnel Zone Plate Imaging
WANG Jing-yu, CHEN Xin-gong, and WANG Xiao-fang
The imaging characteristics of a Kirkpatrick-Baez (KB) mirror were studied using a home-developed code.The numerical recipe of the code was based on coordinate transformation of ray tracing.The spatial resolution and the field of view were obtained.For given parameters,the properties of the KB mirror imaging were compaThe imaging characteristics of a Kirkpatrick-Baez (KB) mirror were studied using a home-developed code.The numerical recipe of the code was based on coordinate transformation of ray tracing.The spatial resolution and the field of view were obtained.For given parameters,the properties of the KB mirror imaging were compared to that of a Fresnel zone plate (FZP),and the application range of the two imaging techniques was given.The KB mirror has a relatively high efficiency.Its spatial resolution is 0.71 μm in the centre of the field of view,but decreases to 6 μm as the object position deviates from the field-of-view center by ±200 μm,thus it is suitable for small field-of-view imaging.The FZP can realize a higher spatial resolution up to 0.39 μm and the resolution almost unchanges within ±13 mm field of view,which can be applied to large field-of-view,high-resolution X-ray imaging.imaging..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2158 (2010)
Redundancy Encoding Method for Three-dimensional Shape Measurement Based on Binary Spatio-temporal Encoded Illumination
XUE Kang, and LI Yong
Abstract:In three-dimensional shape measurement, some regions of the objects are unable to be decoded or decoded incorrectly, using binary spatio-temporal encoded illumination due to occlusion, shadow and low-pass filter characteristic of the optical systems etc. To mitigate the problem, a redundancy encoding method waAbstract:In three-dimensional shape measurement, some regions of the objects are unable to be decoded or decoded incorrectly, using binary spatio-temporal encoded illumination due to occlusion, shadow and low-pass filter characteristic of the optical systems etc. To mitigate the problem, a redundancy encoding method was proposed. Two adjacent sections were encoded with the same code and distinguished with their temporal coordinates. According to the redundancy encoding method, measurement results can be checked and some sections can be recovered from incomplete codewords during decoding. Compared with the original method, more valid points were obtained and the reliability of the decoding results were improved with proposed method, which presents more information for error correction..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2163 (2010)
Digital Holographic Technique with Large Viewing Angle Based on Image Filter
DENG Li-jun, WANG Hui, and MA Li-hong
To generate digital holograms with a large viewing angle, a digital holographic technique based on filter imaging is proposed. Using the off-axis image plane holography, a low-pass filter is placed at the spatial frequency plane of the 4F coherent imaging system, in order to make the object wave (satisfied CCD resolutiTo generate digital holograms with a large viewing angle, a digital holographic technique based on filter imaging is proposed. Using the off-axis image plane holography, a low-pass filter is placed at the spatial frequency plane of the 4F coherent imaging system, in order to make the object wave (satisfied CCD resolution ratio) interfere with the reference wave, and the loss-pass filter and imaging areas are controlled to record the sub-holograms for different spectra in turn. In digital holographic reconstruction, all sub-holograms are carried on numerical Fourier transform, and the corresponding spectra are reconstructed which are also stitched to form a whole spectrum of object wave. Then, a large viewing angle reconstruction image can be obtained by digital holography. The proposed technique is applied to the three-dimensional profile measurement of a sewing needle, and the experimental results prove the accuracy of this technique..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2168 (2010)
A Novel Method for Projection Gray Sinusoidal Grating Fabrication
CHENG Ping, ZHANG Chao, ABLIZ Abdugheni, CHEN Xiang-dong, and WU Ben-ke
Traditional methods are difficult to fabricate the gray sinusoial grating in structured-light three-dimension projection measuring system, and if replaced by Ronchi grating will affect the measurement accuracy. A novel method for gray sinusoidal grating plate fabrication is presented. Through the analysis of transmittaTraditional methods are difficult to fabricate the gray sinusoial grating in structured-light three-dimension projection measuring system, and if replaced by Ronchi grating will affect the measurement accuracy. A novel method for gray sinusoidal grating plate fabrication is presented. Through the analysis of transmittance curve of holographic silver halide plate, the reason that sinusoidal interference pattern of contrast degree for 1 can not be linearly recorded and transformed is pointed out. A new method of linear recording is proposed,which provides a pre-exposure uniformly incoherent light bias point. The experimental results show that the sinusoidal interference fringes record of symmetrical two-beam can be obtained by the spatial filtering method, and the linear and high contrast record of sinusoidal interference fringe can be achieved by exposure controlled accurately in the linear region of the holographic silver halide plate..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2174 (2010)
Computer Generated Holography Based on 3-D Fourier Spectra
LIU Dao-jin, and HUANG Su-juan
A new method was proposed to synthesize computer-generated hologram of three-dimensional object. According to the principles of paraboloid of revolution in three-dimensional Fourier space, spectra information of three-dimensional object was gathered. A series of projection images of three-dimensional object was recordeA new method was proposed to synthesize computer-generated hologram of three-dimensional object. According to the principles of paraboloid of revolution in three-dimensional Fourier space, spectra information of three-dimensional object was gathered. A series of projection images of three-dimensional object was recorded by circular scanning method, then the information of the projection spectra in several semi-circles form was extracted and encoded into computer-generated hologram based on conjugate-symmetric extension. In the traditional method, the spectrum information is extracted in a circular form from each projection. In the case of an equal number of projections, the proposed method can extract more spectrum information. So it can effectively improve utilization of each projection, and the quality of reconstructed image from computer-generated hologram. Experimental results validate the proposed method and its good performance..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2178 (2010)
Spectral Fine Structure, Local Structure and Jahn-Teller Effect of α-Al2O3 Crystal Doped with Ni2+
YIN Chun-hao, JIAO Yang, SHEN Gan, LI Fu-qiang, and ZHU Shan-shan
The completely diagonalized Hamiltonian matrixes of order 45 of 3d2/3d8 ion configurations in the trigonal symmetry sites were established by means of crystal field theory and irreducible representation method. The Hamiltonian matrixes include four kinds of microscopic magnetic interactions: spin-orbit interaction, spiThe completely diagonalized Hamiltonian matrixes of order 45 of 3d2/3d8 ion configurations in the trigonal symmetry sites were established by means of crystal field theory and irreducible representation method. The Hamiltonian matrixes include four kinds of microscopic magnetic interactions: spin-orbit interaction, spin-spin interaction, spin-other-orbit interaction and other-orbit-other-orbit interaction. The spectral fine structure and crystal local structure of Ni2+∶α-Al2O3 crystal were calculated by the Hamiltonian matrixes. Meanwhile, the four kinds of interactions and their effects to the spectral fine structure and the Jahn-Teller effect were also analyzed. The calculated values were conformed with the experimental values. The results show that doping Ni2+ ions cannot change the symmetry, and it was discovered and explained the existence mechanism of Jahn-Teller effect in spectral fine structure of α-Al2O3 doped with Ni2+..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2183 (2010)
Soft X-ray Streak Camera with Dynamic Range of 2000 and Picosecond Temporal Resolution
LIAO Hua, HU Xin, YANG Qin-lao, NIU Li-hong, ZHANG Jin-song, and ZHOU Jun-lan
A new streak camera with more wider dynamic range and picosecond temporal resolution for soft X-ray was developed. The photocathode′s working area is 30 mm in diameter, and its focusing voltage is reduced to 8 kV to prevent electrical discharge. A post-accelaration system was introduced into the image tube for improvinA new streak camera with more wider dynamic range and picosecond temporal resolution for soft X-ray was developed. The photocathode′s working area is 30 mm in diameter, and its focusing voltage is reduced to 8 kV to prevent electrical discharge. A post-accelaration system was introduced into the image tube for improving the phosphor screen′s quantum efficiency largely, and an external image intensifier with wide dynamic range was adopted. Experimental evaluation was carried out by means of a picosecond laser, and the results show that the dynamic range of more than 2000 can be achieved..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2190 (2010)
Shaft Design and Errors Analysis of the Composite Optical Encoder
LIANG Li-hui, WAN Qiu-hua, and SHE Rong-hong
To improve the composite precision optical encoder,a large hollow shaft precision shaft was designed using the close packing ball bearing and the close-packing arranging bearing,and errors of the shaft were analyzed.With this method,the radial shaft precision shaft is δ<3 μm,which solves the poor accuracy problem ofTo improve the composite precision optical encoder,a large hollow shaft precision shaft was designed using the close packing ball bearing and the close-packing arranging bearing,and errors of the shaft were analyzed.With this method,the radial shaft precision shaft is δ<3 μm,which solves the poor accuracy problem of the large hollow shaft shafting and improves the composite encoder angle measurement accuracy.The experimental results show that the proposed design can meet the composite optical encoder whose accuracy σ <2″..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2194 (2010)
Monte Carlo Simulation on LEDs Graded-Refractive-Index-Encapsulation
YU Ren-yong, JIN Shang-zhong, LIANG Pei, CEN Song-yuan, and WANG Le
Light propagation in nanoparticle-loaded encapsulants is simulated based on the method of Monte Carlo, referring to the multilayer graded refractive index structure for LED encapsulants. And the influence of scattering coefficient on transmittance is analyzed. The results show that the transmittance decreases with scatLight propagation in nanoparticle-loaded encapsulants is simulated based on the method of Monte Carlo, referring to the multilayer graded refractive index structure for LED encapsulants. And the influence of scattering coefficient on transmittance is analyzed. The results show that the transmittance decreases with scattering coefficient. For a given number of layers, the encapsulants will yield maximum transmittance if the refractive index value of each layer is optimized. The nanoparticle-loaded encapsulant consists of multiple layers with refractive-index values that gradually decrease, transmittance will be higher than in traditional non-graded encapsulants, and will improve light extraction efficiency of LED..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2200 (2010)
Influence of Reflector Shape on the Intensity Modulation of Fiber Optical Distance Sensors
SHAN Ming-guang, PENG Huan, ZHONG Zhi, and GUO Li-li
To study the impact of reflector shape on the performance of a reflective intensity-modulated fiber optical distance sensor with single mode illumination, a theoretical model was established based on the assumption that the single mode fiber output light field is the modified approximate Gaussian distribution. By introTo study the impact of reflector shape on the performance of a reflective intensity-modulated fiber optical distance sensor with single mode illumination, a theoretical model was established based on the assumption that the single mode fiber output light field is the modified approximate Gaussian distribution. By introducing the reflector shape factor, the influence discipline of the reflector shape factor on the intensity modulation characteristics was analyzed. Simulation results indicate that for concave reflector, as the radius of curvature increases, the sensitivity of the back slope becomes larger and the linear range of the back slope becomes smaller while those of the front slope remain almost unchanged. However, for convex reflector, as the radius of curvature increases, the sensitivity of the back slope becomes smaller and the linear range of the back slope becomes larger while those of the front slope also remain almost unchanged. As the radius of curvature increases, the effect of the nonplanar reflector becomes weaker until it disappears..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2204 (2010)
Calculation of Terahertz Pulse Propagation and Detection in〈331〉 ZnTe Single Crystal
WANG Reng, LIN Xing-chao, ZHANG Li-ping, ZHANG Ke-feng, JIAO Cui-ling, LU Ye, SHAO Xiu-hua, LU Rong, GE Jin, HU Shu-hong, and DAI Ning
The THz pulses generation of 〈331〉-oriented ZnTe as emitter via its optical rectification were reported. Compared with 〈110〉、〈111〉-oriented ZnTe crystal, the 〈331〉-oriented ZnTe could even emit THz pulse. When the crystal oriented angle was 00 or 1800, the THz pulse amplitude from 〈331〉-oriented could be equal to 〈111〉The THz pulses generation of 〈331〉-oriented ZnTe as emitter via its optical rectification were reported. Compared with 〈110〉、〈111〉-oriented ZnTe crystal, the 〈331〉-oriented ZnTe could even emit THz pulse. When the crystal oriented angle was 00 or 1800, the THz pulse amplitude from 〈331〉-oriented could be equal to 〈111〉-oriented, higher than 〈110〉-oriented. The THz pulses detection performance of 〈331〉-oriented ZnTe as detector was calculated via the electro-optical effect. The theoretical calculation from 〈331〉 ZnTe emitter demonstrated a direct way to optimize the working efficiency of a terahertz emitter..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2209 (2010)
Design and Analysis of Lunar-based Tracking Turntable for Earth Observation
LI Zhao-hui, and CHEN Bo
Aiming at the mechanical condition during the moon landing, complex environment lunar surface features, and strict weight requirements, a tracking turntable for lunar-based earth observation was designed which consists of two main components: horizontal shaft & elevation actuator modules, and vertical shaft & aAiming at the mechanical condition during the moon landing, complex environment lunar surface features, and strict weight requirements, a tracking turntable for lunar-based earth observation was designed which consists of two main components: horizontal shaft & elevation actuator modules, and vertical shaft & azimuth actuator modules. In addition, Hour sensors were selected as the rotation position detector of elevation and azimuth shafts, and the pointing accuracy is better than 0.1°. An effective tracking turntable design configuration, optimized structure of supporter and selection of material were performed based on the finite element analysis method, and the stiffness of axis system and transmission accuracy of actuator module were analyzed to obtain the trade-off design with better capabilities of deep space environmental adaptability. To qualify the design for the specific mission requirements, the vibration and thermal vacuum tests were carried out with the result of 41 Hz eigenfrequencies and the required running temperature changing range (—40℃~+80℃). The experimental results show that the proposed design has advantages of compact volume, light weight and high reliability..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2215 (2010)
Computer-aided Alignment of Off-axis Aspheric Mirrors in Null Testing
CHEN Qin-fang, LI Ying-cai, MA Zhen, LI Xu-yang, and GUO Yong-xiang
Abstract:Based on the principle of null lens,a new method of error-separation was proposed in null testing.A mathematic model was developed to separate misalignment-induced aberration from the test result.The method was used in the simulations of an off-axis aspheric mirror.The wavefront aberration induced by misalignmAbstract:Based on the principle of null lens,a new method of error-separation was proposed in null testing.A mathematic model was developed to separate misalignment-induced aberration from the test result.The method was used in the simulations of an off-axis aspheric mirror.The wavefront aberration induced by misalignment is 0.0026λRMS (λ=632.8 nm) after the alignment,compared with 0.2332λRMS before the alignment,which reflects that this method has high accuracy and can improve the efficiency of the null test..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2220 (2010)
Robust Background Subspace Based Anomaly Detection Algorithm for Hyperspectral Imagery
PU Xiao-feng, LEI Wu-hu, HUANG Tao, and WANG Di
In RX anomaly detection algorithm, when backgroud being contaminated from anomaly pixels, the local backgroud covariance matrix estimation can not reflect backgroud distribution accurately, which results in low detection capacity. To overcome this problem, a new method based on the robust background subspace was proposIn RX anomaly detection algorithm, when backgroud being contaminated from anomaly pixels, the local backgroud covariance matrix estimation can not reflect backgroud distribution accurately, which results in low detection capacity. To overcome this problem, a new method based on the robust background subspace was proposed. Utilizing the spatial rank depth, the position of every sample relative to the distribution space of whole background samples could be measured. Samples which locating at the edge of the distribution space were regarded as anomaly, and being mapped into the distribution space. In this way, the local background covariance matrix was estimated, and the principal component analysis as background space was obtained which can characterize background more accurately. An anomaly detection model was constructed on this subspace using mahalanobis distance. The effectiveness of the proposed method is validated by experimental results from simulated and real data..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2224 (2010)
Optical System Design of an Integrated Dual-line Array Stereoscopic Mapping Camera
YAO Gang, FU Dan-ying, and HUANG Ying
To conform the design requirements of optical system for dual-line array stereoscopic mapping camera, an off-axis three-mirror reflective system was designed and its image quality was analyzed. The MTF of the optical system is near 0.6 (at 50 lp/mm), relative distortion is less than 3×10－4，and the calibrated absolTo conform the design requirements of optical system for dual-line array stereoscopic mapping camera, an off-axis three-mirror reflective system was designed and its image quality was analyzed. The MTF of the optical system is near 0.6 (at 50 lp/mm), relative distortion is less than 3×10－4，and the calibrated absolute distortion is less than 20 μm. The optical design was optimized to meet the nominal optical performance. At the same time, in order to meet the dimensional requirements，mechanics constraints and low mass required for space application, a new layout of optical systems was adopted, which has the unique merits of miniaturization and lightening. The optical systems could be assembled in the same mechanical structure，of which the primary mirrors were assembled and aligned on the same deck with the required intersection angle，so it has advantages of highly structure stabilization and environment adaptability..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2229 (2010)
Surface Plasmon Polaritons of the Metamaterial Symmetric Five-layered Structures
ZHANG Hui-fang, ZHAO Yu-jing, TAO Feng, REN Hai-hong, WANG Yan, BAI Li-hua, DAI Ye, and YAN Xiao-na
The surface plasmon polaritons (SPPs) properties of symmetric five-layered structures composed of three kinds of materials:left-handed material (LHM),negative dielectric permittivity material (NDPM),and dielectric are investigated.The existence regions,dispersion relations,and excitation of the p and s polarized SPPs iThe surface plasmon polaritons (SPPs) properties of symmetric five-layered structures composed of three kinds of materials:left-handed material (LHM),negative dielectric permittivity material (NDPM),and dielectric are investigated.The existence regions,dispersion relations,and excitation of the p and s polarized SPPs in several types of symmetric five-layered structures are studied in detail. It is shown that the properties of SPPs in different frequency regions are strongly dependent on the composite materials and their sequencing of the symmetric five-layered structures. It is also found that more layers lead to more surface dispersion branches,and more surface polarization modes in pass-band frequency.The intensified transmission can be realized when p and s polarized SPPs resonance.The possibility of exciting and observing SPPs by Attenuated Total Reflection (ATR) technique is also discussed..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2234 (2010)
Design of Ceramic Multilayer Packing Board for Innovative Multi-channel Long Wave Photoconductive Linear Device
WU Wen, and LIU Da-fu
An optimum packaging structure of photoconductive infrared detector which is a 7-channel device and made in the form of linear array was proposed. After a brief introduction to the basic elements in dewar assembly, the development of dewar assembly at home and abroad was reviewed by examining the assembly design. BasedAn optimum packaging structure of photoconductive infrared detector which is a 7-channel device and made in the form of linear array was proposed. After a brief introduction to the basic elements in dewar assembly, the development of dewar assembly at home and abroad was reviewed by examining the assembly design. Based on the review of previous work, the performances of three different designs were compared: the first design provided direct electronic feed-through and contacted points with a number of cables and wire feeds, yet fails to a significant increase in the size of the device; the second one adopted Ceramic Pin Grid Array as the package, however this design was unavailable due to the lack of the optimal contact points; the third design absorbed the idea of “time-sharing” with both thick film and thin film technology. Furthermore, the third one of an innovative cabling solution enabled the infrared detect or to offer high performance and good response speed by using flexible cables..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2241 (2010)
Fast Correlation Matching Based on Fast Fourier Transform and Integral Image
YIN Song-feng, WANG Yi-cheng, CAO Liang-cai, JIN Guo-fan, and LING Yong-shun
In order to overcome the computation complexity of traditional correlation matching algorithm, a fast correlation matching algorithm is proposed based on fast Fourier transform and integral image. By analyzing and simplifying the equation of correlation coefficient, fast Fourier transform is employed to calculate the cIn order to overcome the computation complexity of traditional correlation matching algorithm, a fast correlation matching algorithm is proposed based on fast Fourier transform and integral image. By analyzing and simplifying the equation of correlation coefficient, fast Fourier transform is employed to calculate the correlation between the template image and the base image, and integral image is employed to compute the window integral of the gray value of the base image and its energy. The computation complexity of the proposed algorithm is approximately independent on the size of the template image and thus is greatly decreased, without changing the results of traditional correlation matching. Experimental results for image matching under different illumination conditions and object tracking in complex situations show that the proposed algorithm is robust to interferences, and its implementation efficiency is 1 to 2 order times faster than traditional correlation matching algorithm..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2246 (2010)
Remote Sensing Image Compression Based on Reversible Integer Time Domain Lapped Transform
WANG Lei, WU Jia-ji, and BAI Jing
A reversible non-multiplying integer time domain lapped transform was introduced, and a new progressive lossy-to-lossless compression system was designed based on this transform technique. Completely lossless compression images and high-quality lossy reconstructed images could be obtained from a single code-stream usinA reversible non-multiplying integer time domain lapped transform was introduced, and a new progressive lossy-to-lossless compression system was designed based on this transform technique. Completely lossless compression images and high-quality lossy reconstructed images could be obtained from a single code-stream using the proposed compression system. RTDLT improved the transform efficiency of DCT by adding pre-and-post-filters, and it couldrealize reversible integer transform by multi-lifting based on matrix factorization. Simulation results show that RTDLT-based compression system obtains comparable or even higher compression ratio in lossless compression than that of JPEG2000 and HD-Photo, better rate-distortion performance in lossy compression in most cases, and also gratify subjective visual quality..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2251 (2010)
Target and Target Shadow Segmentation of Synthetic Aperture Radar Image Based on the Pseudo Wigner distribution Decomposition
LIU Cong, LI Yan-jun, and ZHANG Ke
In order to sovle the problem of expensive cost and the interference of cross terms in two-dimensional (2D) Wigner-Ville distribution (WVD) category, a novel target and target shadow segmentation method of synthetic aperture radar (SAR) images based on the two-dimensional Pseudo Wigner-Ville distribution (PWVD) decompoIn order to sovle the problem of expensive cost and the interference of cross terms in two-dimensional (2D) Wigner-Ville distribution (WVD) category, a novel target and target shadow segmentation method of synthetic aperture radar (SAR) images based on the two-dimensional Pseudo Wigner-Ville distribution (PWVD) decomposition were proposed. Firstly, 2D local energy maps of every pixel of original SAR image were obtained through local 2D-PWVD transform to SAR image. Then, the resultant data which are 2D local energy maps of every pixel of original SAR image could be arranged as N energy maps which are the same size with original SAR image. Finally, the different processing methods to the resultant data in frequency dimension were adopted according to different energy maps. The marker region image of target and target shadow was formed through adding the filtered energy maps.The segmentation experiment for MSTAR chips were taken using the proposed method.The comparisons between segmentation images of our method and segmentation images of the algorithm based on distance or azimuth of max energy, and between segmentation images of our method and segmentation images of the compounding segmentation algorithm based on two-parameter CFAR and Markov Random Field were carried out. The results show that the segmentation images by the presented algorithm preserve the abundant detail information of original images..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2257 (2010)
Properties Investigation of Laser-induced Plasma Sound Waves in Liquids
LI Sheng-yong, RAO De-hu, SHEN Zhong-hua, and NI Xiao-wu
By the piezoelectric transducer hydrophone, laser-induced plasma sound waves in liquids were measured through experiments. Wavelet transform was applied to analyze the spectra characteristics of these signals acquired at different laser energy,different metal solid boundary and different laser wavelength.The results shBy the piezoelectric transducer hydrophone, laser-induced plasma sound waves in liquids were measured through experiments. Wavelet transform was applied to analyze the spectra characteristics of these signals acquired at different laser energy,different metal solid boundary and different laser wavelength.The results show that laser-induced plasma sound waves frequency range is 0~150 kHz,and changes of the laser energy, the metalboundary underwater and the laser wavelength have little effect on distribution of frequency of waves.Most energy of plasma sound waves is concentrated at the a6 level,and the proportion of the whole energy decreases with the increase of ionization energy of metal.The main frequency of sound waves is within 0~10 kHz,and the frequency peak is 5 kHz..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2263 (2010)
3D Points Cloud Object Recognition Based on Surface Segmentation
WEI Yong-chao, LIU Chang-hua, and DU Dong
A 3D point cloud object recognition algorithm was studied based on the local descriptor. The information of vector and shape index value of the point cloud were calculated, and then according to the shape index, feature points were extracted. Based on the Euclidean distance and vector angle, points cloud were segmentedA 3D point cloud object recognition algorithm was studied based on the local descriptor. The information of vector and shape index value of the point cloud were calculated, and then according to the shape index, feature points were extracted. Based on the Euclidean distance and vector angle, points cloud were segmented into different patches centered on feature points. From the Equidistant partition on each patch, 3D European-style concentric circles were obtained. The vector angle and geodesic distance variation on the sample points of each circle were important information, so the description of three-dimensional objects could be transformed into two two-dimensional curves, the normal vector curves and the geodesic distance curves. One model objects database would be established firstly. Through comparison of the descriptions of tested object with the model database, some potential recognition results could be found. With the finally iterative closest point algorithm, the final recognition result would be obtained. Experimental results with real objects, and time consuming comparison with other algorithms were presented to demonstrate the effectiveness of the proposed algorithm..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2268 (2010)
Digital Processing of Wake Images Based on MATLAB
CUI Hong, CHANG Yang, and ZHANG Jian-sheng
The working principles and methods of wake images digital processing system were introduced. The gray-scale transformation, filtering, Canny marginalization, binary transformation and histogram transformation of two wake flow images were carried on, the speed of which are 30 km/h and 40 km/h respectively, using MATLAB The working principles and methods of wake images digital processing system were introduced. The gray-scale transformation, filtering, Canny marginalization, binary transformation and histogram transformation of two wake flow images were carried on, the speed of which are 30 km/h and 40 km/h respectively, using MATLAB software, experimental results were analyzed,and the speed of the ship wake edge angle, edge curvature and histogram peak change were obtained. The research results provide a basis for wave images entering the informationization system..
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2274 (2010)
[in Chinese]
[in Chinese]
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2279 (2010)
[in Chinese]
[in Chinese]
Acta Photonica Sinica
- Publication Date: Aug. 24, 2021
- Vol. 39, Issue 12, 2298 (2010)
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