2019
2019
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Record 241 of
Title:Physical simulation of micro-nano satellite photoelectric tracking by reaction wheel
Author(s):Tao, Junming(1,2); Liu, Jun(2); Li, Zhiguo(2); Li, Xin(2); Cheng, Zhiyuan(2)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 48 Issue: 10 DOI: 10.3788/IRLA201948.1013003 Published: October 25, 2019Abstract:To verify the feasibility of tracking moving targets of micro-nano satellite using reaction wheel as actuator to adjust attitude, the physical simulation system of micro-nano satellite photoelectric tracking based on single-axis air-bearing platform was designed. Firstly, in order to improve the accuracy of physical simulation system, the disturbance torques of reaction wheel and air-bearing platform were analyzed separately; Secondly, aiming at disturbance torques and asymmetry of acceleration and deceleration time constants of reaction wheel itself, a flywheel control strategy combining gain scheduling and moment compensation was designed; Then, the tracking control system of analog micro-nano satellite was designed by using double closed-loop with velocity-forward control structure; Finally, in order to test the tracking performance of the simulation system, the tracking experiment of one-dimensional target with sinusoidal motion was completed. The experiment shows that the tracking accuracy reaches 0.4° for sinusoidal moving targets with maximum velocity of 9 (°)/s and maximum acceleration of 4.5 (°)/s2, which demonstrates that the micro-nano satellite using reaction wheel as actuator can track moving targets by attitude maneuver. ? 2019, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20194807747251 -
Record 242 of
Title:Simultaneous super-resolution reconstruction based on plane array staring remote sensing images
Author(s):Yang, Rui(1,2); Liu, Zhaohui(1); She, Wenji(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 48 Issue: 1 DOI: 10.3788/IRLA201948.0126002 Published: January 25, 2019Abstract:A group of images for one scene can be obtained by plane array staring remote sensing system. So researchers often use multi-frame image super-resolution reconstruction to produce images with higher spatial resolution. However, most of reports regard super-resolution reconstruction as an isolated part ignoring that geometric parameters of imaging system have the ability to optimize the reconstruction model. Therefore, the influence of attitude angle on resolution changes in different directions was analyzed particularly. Meanwhile, the corresponding anisotropic blur estimation was presented to improve the accuracy of discrimination model. Because of the matching parameter as a significant role in super-resolution reconstruction, for improving the accuracy of the matching parameter estimation and decreasing the global initial matching error caused by the system, the algorithm of simultaneously optimizing super-resolution image and matching parameters based on maximum a posteriori estimation was proposed. This method takes advantage of the useful information of imaging system and improve the robustness of matching parameter by synchronous optimizing. The experimental results demonstrate that the method of our paper is better than existed algorithms in detail information and definition observing by eyes. In addition, the mean square error was reduced 0.3 times, and the information entropy was increased 1.2 in average. ? 2019, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20191106621846 -
Record 243 of
Title:Electrically tunable temporal imaging in a graphene-based waveguide
Author(s):Xie, Peng(1,2,3,4); Wen, Yu(5); Wan, Zishen(2,4); Wang, Xinyu(1,3); Liu, Jiarui(6); Yang, Wenqiang(1,3); Li, Xiaofeng(1); Wang, Yishan(1,3)Source: Japanese Journal of Applied Physics Volume: 58 Issue: 5 DOI: 10.7567/1347-4065/ab0c52 Published: 2019Abstract:We propose an electrically tunable temporal imaging system (TIS) based on four-wave mixing in a dispersion engineered graphene-based waveguide, which could realize a magnification factor of 1000× for a signal consisting of two 100-fs-wide pulses separated by 500 fs and a large working bandwidth of about 700 nm. The TIS was analyzed by solving the couple-mode equations in detail. It was demonstrated that the working wavelength range could be tuned via a small disturbed bias voltage applied to the graphene layer without changing the geometric structure of the waveguide. These results provide attractive insights for potential applications in integrated optics and optical communications. ? 2019 The Japan Society of Applied Physics.Accession Number: 20192507079903 -
Record 244 of
Title:Research on sub-micron measurement methods of M55J carbon fibre/cyanate ester composites
Author(s):Li, Yan(1,2); Ge, Wenjie(1); Jiang, Wenge(3)Source: Journal of Engineering Volume: 2019 Issue: 23 DOI: 10.1049/joe.2018.9225 Published: December 1, 2019Abstract:In view of the axial dimensional stability of the main loaded cylinder of the space camera, the thermal expansion characteristics of the carbon fibre M55J/cyanate ester (CE) composite were studied. In this paper, the coefficient of thermal expansion (CTE) of four kinds of carbon fibre composites used in aerospace are analysed and measured in both directions. The results show that the CTE of M55J/CE composite is negative, which cannot be achieved by carbon/epoxy composite. According to this characteristic, the layering mode of M55J/CE laminates was optimised, The CTE of M55J/CE laminates was analysed by the finite element method. Then the loaded cylinder was developed using the optimal ply program. Two different measuring methods, ‘Heating blanket/Three-coordinate measurement’ and ‘High–low temperature chamber/submicrometer displacement detector measurement method’ were proposed to measure the CTE of the loaded cylinder, and the advantages and disadvantages of the two measuring methods are also analysed. The test results were compared, which verified the credibility of the measurement method and data, The test results of ‘High–low temperature chamber/Submicrometer displacement detector measurement method’ were closer to the laminate, which laid the foundation for engineering applications. ? 2019 Institution of Engineering and Technology. All rights reserved.Accession Number: 20200608138558 -
Record 245 of
Title:Practical superoscillation element design for far field non-scanning superresolution imaging
Author(s):Xie, Qingkun(1,2); Jiang, Yanru(1,2); Qu, Enshi(1); Ren, Liyong(1)Source: Proceedings of SPIE - The International Society for Optical Engineering Volume: 10840 Issue: DOI: 10.1117/12.2506724 Published: 2019Abstract:Superoscillation is a promising method to realize superresolution imaging. Nevertheless, in the point spread function (PSF) of previous superoscillation imaging systems, compared to the several orders of magnitude higher intensity in side-lobes, the extremely small intensity in the focal-spot is a severe constraint for practical applications. In this paper, we creatively segment the conventional superoscillation lens into two simple-fabrication portions to generate the superoscillation optical field and realize superresolution imaging in a local field of view (LFOV). We then analyze the contribution of different portions of the entrance pupil to the system's resolution and propose a novel superoscillation element (NSOE) design to effectively reduce the intensity of side-lobes. We end by reporting our recent results on the imaging of complex targets, and the validity and potential applications of superresolution imaging is well demonstrated. ? 2019 SPIE.Accession Number: 20190706497324 -
Record 246 of
Title:Polarization properties of calibration reflector system in the polarization-modulated space laser communication
Author(s):Chen, Guoqing(1,2); Xue, Bin(1); Yang, Jianfeng(1); Zhao, Yiyi(1); Wang, Xingfeng(1,2); He, Jiawei(1,2)Source: Optics Communications Volume: 430 Issue: DOI: 10.1016/j.optcom.2018.06.058 Published: 1 January 2019Abstract:S-polarization light and p-polarization light are mutually cross orthogonal, which can be used as signal light for emitting and receiving in the polarization-modulated space laser communication, respectively. Due to the retro reflection characteristics of the corner cube retroreflector (CCR), it is widely used as a calibration reflector system in the polarization-modulated space laser communication. The polarization states of the incident light will be change owing to the total internal reflection (TIR) of uncoated rear surface, in addition, each of the six propagation trips will in general produce a different output polarization. For the calibration reflector system in the polarization-modulated space laser communication, the polarization state of the received light, especially the intensity ratio of the p-polarization component, needs to be clarified. In this paper, a framework is presented to calculate polarization by ray tracing through CCR with arbitrary input polarization states and incident angles. On this basis, the relationships between intensity ratio of the p-polarization component in the received light of each propagation trip and the incident light with different polarization states at normal incidence as well as the circular polarized light at incident angles within ± 15°analyzed. Theoretical analysis and experiments have guiding significance for the development of the polarization-modulated space laser communication. ? 2018Accession Number: 20183605788147 -
Record 247 of
Title:Application and optimum design of flexible shaft in satellite optical communication
Author(s):Zhang, Furui(1,2); Ruan, Ping(1); Han, Junfeng(1)Source: Hongwai yu Jiguang Gongcheng/Infrared and Laser Engineering Volume: 48 Issue: 8 DOI: 10.3788/IRLA201948.0818001 Published: August 25, 2019Abstract:For the shortcomings of backlash shaft, friction and clearances in coarse tracking system of satellite optical communication, a scheme of using a flexible shaft to support the terminal was presented. The principle of flexible shaft in satellite optical communication was presented. Then the characteristics of flexibility in working direction and stress in thinnest incision were analyzed. According to the key point deflection, the rotation error angle expression was derived and its influence on capture probability was analyzed. Based on the research of flexible shaft characteristics, the flexible hinge was optimized by genetic algorithm. The results are as follows: the flexibility in working direction is 0.768 rad/N·m, the stress of thinnest incision is 1.768 e +8 Pa and the rotary error angle is 343 μrad. Finally, the finite element method was utilized to verify the design consequences, the relative error of the three indexes was less than 3.5%, which proved that the design was reliable. This study can provide some reference for flexible shaft design in satellite optical communication terminal. ? 2019, Editorial Board of Journal of Infrared and Laser Engineering. All right reserved.Accession Number: 20194207544449 -
Record 248 of
Title:Investigation of isolation for free space laser communication in the mono-wavelength optical T/R channels
Author(s):Xia, Fangyuan(1,2,3); Yang, Jianfeng(1); Yao, Zhoushi(3); Song, Yansong(3); Ren, Lanxu(3); Tan, Qinggui(3)Source: Optik Volume: 181 Issue: DOI: 10.1016/j.ijleo.2018.12.090 Published: March 2019Abstract:Favorable isolation performance in optical transmitting-receiving (T/R) channels is key to establishing full-duplex bi-directional laser communication links when designing mono-wavelength laser communication terminals. This study proposes a novel design scheme for T/R channels that use a single laser wavelength. The system includes measures such as the deflection at λ/4 wave plate angles, light trap installation at a polarization beam splitter, and removal of polarization analyzers in optimized systems. A mathematical model describing isolation in the optical T/R channels is presented. Three types of factors that affect the isolation of optical T/R channels were analyzed and simulated in detail. The present simulation results show that the roughness of the λ/4 wave plate and the solid angle of the detector field of view are exponentially related to T/R isolation, which can thus be regarded as the most significant factors affecting isolation. According to the present design scheme, the prototype T/R channel was developed for measuring isolation. The measured value (77.8 dB) agrees well with the result determined using the established mathmatical model (77.3 dB). Conclusively, the present theoretical model can provideguidance for optimizing isolation in a mono-wavelength optical channel. Thus, it can be applied extensively in laser communication systems, including inter-satellite networks. ? 2018 Elsevier GmbHAccession Number: 20185306321881 -
Record 249 of
Title:Imaging Enhancement of Light-Sheet Fluorescence Microscopy via Deep Learning
Author(s):Bai, Chen(1); Liu, Chao(1); Yu, Xianghua(1); Peng, Tong(1); Min, Junwei(1); Yan, Shaohui(1); Dan, Dan(1); Yao, Baoli(1)Source: IEEE Photonics Technology Letters Volume: 31 Issue: 22 DOI: 10.1109/LPT.2019.2948030 Published: November 15, 2019Abstract:The complementary beam subtraction (CBS) method can reduce the out-of-focus background and improve the axial resolution in light-sheet fluorescence microscopy (LSFM) via double scanning a Bessel and the complementary beams. With the assistance of a compressed blind deconvolution and denoising (CBDD) algorithm, the noise and blurring incurred during CBS imaging can be further removed. However, this approach requires double scanning and large computational cost. Here, we propose a deep learning-based method for LSFM, which can reconstruct high-quality images directly from the conventional Bessel beam (BB) light-sheet via a single scan. The image quality achievable with this CBS-Deep method is competitive with or better than the CBS-CBDD method, while the speed of image reconstruction is about 100 times faster. Accordingly, the proposed method can significantly improve the practicality of the CBS-CBDD system by reducing both scanning behavior and reconstruction time. The results show that this cost-effective and convenient method enables high-quality LSFM techniques to be developed and applied. ? 1989-2012 IEEE.Accession Number: 20200208022085 -
Record 250 of
Title:Research on dynamic characteristics of space camera focusing platform
Author(s):Cheng, Peng-Hui(1,2); Wu, Meng-Yuan(1)Source: Guangxue Jingmi Gongcheng/Optics and Precision Engineering Volume: 27 Issue: 3 DOI: 10.3788/OPE.20192703.0602 Published: March 1, 2019Abstract:Focusing mechanism is a key part of space cameras. Its dynamic performance greatly affects camera reliability. To analysis the dynamic characteristics, the focusing mechanism platform of a space camera was researched in simulation, where its entry point was the guide, and the model of the guide joint was built with the optimized tandem spring damping element in the finite element model of the focusing mechanism platform. The research obtained dynamic parameters based on the Hertzian contact theory and equalizes the rigidity of the ball screw and the coupling on the guide, and formulates the relation expression and corrected parameter. The corrected parameter was confirmed by a comparative experiment based on the variable of the coupling stiffness, thereby completing the dynamic analysis of the space camera focusing platform. Finally, the research accomplishes the dynamic simulation analysis of the focusing platform with the stated analysis method under different conditions, with a deviation of under 2%, thus demonstrating high accuracy and reliability of the analysis method. ? 2019, Science Press. All right reserved.Accession Number: 20192206992276 -
Record 251 of
Title:Design of Optical System for Multi-band All-sky Airglow Imager
Author(s):Li, Zhan-Tao(1,2); Feng, Yu-Tao(1); Han, Bin(1,2); Li, Yong(1); Sun, Jian(1); Bai, Qing-Lan(1)Source: Guangzi Xuebao/Acta Photonica Sinica Volume: 48 Issue: 5 DOI: 10.3788/gzxb20194805.0522003 Published: May 1, 2019Abstract:In order to reduce the complexity and development cost of the multi-band all-sky imager, a multi-band all-sky imaging optical system with no focusing and high robustness is proposed. A secondary imaging system is composed of a telecentric fisheye lens and a finite conjugate distance imaging lens of the telecentric image. The shelf-level narrow-band filter is placed at the image plane, using H-FK61 and KF2 glasses achieve full system apochromatic. The design results show that the system F number is 2.8, the band range is 427.8~865 nm, the chromatic focal shift is less than 0.048 mm, and the optical transfer functions of the eight observation channels of the system are all above 0.46, which meets the application requirements. The tolerance of filter is very loose. The surface tolerance PV is less than λ/2, the refractive index tolerance is ±0.003, the thickness tolerance is ±0.05, and the shelf-level products can meet the application requirements. Compared with the traditional scheme, the system eliminates the detector focusing mechanism and does not need to use a customized narrow-band filter, which simplifies the system and reduces the cost. ? 2019, Science Press. All right reserved.Accession Number: 20192607089017 -
Record 252 of
Title:Chemical etching mechanisms and crater morphologies pre-irradiated by temporally decreasing pulse trains of femtosecond laser
Author(s):Du, Kun(1); Jiang, Lan(1); Li, Xiaowei(1); Zhang, Hao(1); Wang, Andong(1); Yao, Zhulin(1); Pan, Changji(1); Wang, Zhi(1); Li, Ming(2); Grigoropoulos, Costas P.(3); Lu, Yongfeng(4)Source: Applied Surface Science Volume: 469 Issue: DOI: 10.1016/j.apsusc.2018.10.272 Published: 1 March 2019Abstract:We report the influence of temporally decreasing pulse trains on femtosecond laser-induced chemical etching (FLICE) of fused silica. A systematic comparison of the unshaped pulse and decreasing pulse trains of femtosecond laser for FLICE was conducted, and the differences were interpreted using a plasma model. The results revealed that the decreasing pulse trains not only affected the etching efficiency but also affected the morphology of the etched crater. When an etched crater was pre-irradiated by decreasing pulse trains, it presented a funnel-like shape at the early stage of the etching process, which contrasted with the one pre-irradiated by unshaped pulse. At the later stage of the etching process, the funnel-like shape gradually disappeared, and the crater increased in size. Compared with the unshaped pulse under the same processing conditions, the decreasing pulse trains enhanced the etched crater volume by approximately 18 times. Theoretical calculations based on the plasma model indicated that the free-electron density generated using the unshaped pulse was much higher than that generated by the decreasing pulse trains in skin layer of the sample during the first few hundred femtoseconds. The high free-electron density increased the reflectivity in skin layer of the sample; thus, the tail part of the incident pulse was strongly reflected. Consequently, the laser energy deposition into the fused silica sample decreased, eventually led to a low etching efficiency. ? 2018Accession Number: 20184506049935