2021

• Record 409 of
  
  Title:Trapping performance of holographic optical tweezers generated with different hologram algorithms
  
  Author(s):He, M.R.(1,2); Liang, Y.S.(3); Bianco, P.R.(4); Wang, Z.J.(3); Yun, X.(3); Cai, Y.N.(1); Feng, K.(3); Lei, M.(2,3)
  Source: AIP Advances  Volume: 11  Issue: 3  DOI: 10.1063/5.0033186  Published: March 1, 2021  
  Abstract:Quantitative measurement of small forces and small displacement using holographic optical tweezers (HOTs) is finding increasing applications due to the features of non-contact and high accuracy manipulation. Although hologram optimization algorithms have been widely reported, the holographic optical trapping performance relying on the algorithms has not been studied systematically. In this paper, we investigated the force measuring the performance of various types of HOTs generated with six different hologram algorithms (GSW, GAA, GS, SR, S, and RM). To do this, we built up a HOT instrument and compared the light fields' intensity distribution, trap stiffness, efficiency, and calculation time of multi-point trap arrays generated by six hologram algorithms with this setup. Our work will provide a better understanding of the performance of different hologram algorithms in HOTs. © 2021 Author(s).
  Accession Number: 20211210123389
• Record 410 of
  
  Title:Applications and development of micro-or nano-metric multi degree of freedom adjusting displacement scaling mechanisms for primary mirror
  
  Author(s):Hu, Bin(1); Li, Chuang(2); Zhu, Qing(1); Ye, Jing(1,2)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 11761  Issue:   DOI: 10.1117/12.2586744  Published: 2021  
  Abstract:For large aperture and high-resolution space optical cameras, the focusing requirements caused by different resolution requirements, or the requirements for the segmented primary mirror for deployable telescopes or on-orbit assembly space telescopes, the micro-or nano-metric multi degree of freedom adjusting of the primary mirror or the segment mirror is one of the inevitable development trends of the active optical system. According to the different degrees of freedom involved in the primary mirror adjustment, the micro-or nano-metric multi degree of freedom adjusting displacement scaling mechanisms of the monolithic and segmented primary mirror are studied. The development history and structural characteristics of multi degree of freedom adjusting displacement scaling mechanisms including rigid lever type, gear deceleration type, hydraulic mechanism type and compliant hinge type, as well as their research status and application fields, are introduced. The performance characteristics and applications of various displacement scaling mechanisms are analyzed and compared. Finally, according to the application requirements of space telescopes in the future, the development trend of multi degree of freedom (DOF) adjusting displacement scaling mechanism for segmented primary mirror is proposed. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
  Accession Number: 20210509874612
• Record 411 of
  
  Title:Study on assembly technology of primary and secondary mirror system based on truss structure
  
  Author(s):Peng, Wang(1); Xing, Song(1); Xiao-Hua, Hou(1); Zhong, Shen(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12070  Issue:   DOI: 10.1117/12.2603955  Published: 2021  
  Abstract:According to the assembly requirements of the space camera's primary and secondary mirror system, this paper proposes the assembly process of carbon fiber truss fuselage's primary and secondary mirror system based on adhesive error compensation technology. The process starts from a system point of view, the adhesive bonding of the truss fuselage was unified with the assembly of the primary and secondary mirror system. The adhesive technology was used to compensate the machining errors of the structural parts, and the adhesive bonding of the truss fuselage and the optical axis consistency assembly of primary and secondary mirror system are realized in the process of one adjustment. According to this assembly process idea, the assembly process of primary and secondary mirror system was designed. Firstly, the optical axis of the primary mirror and the optical axis of the secondary mirror were calibrated by the principle of autocollimation, and the optical axis was guided to the cross reticule as the reference for subsequent installation and adjustment. Secondly, in order to realize this process method, the assembly and adjustment platform of the primary and secondary mirror was designed and built. In addition, the factors that affect the assembly precision of the primary and secondary mirror system are analyzed one by one, and the calculation method of system assembly error is obtained. This assembly method has been successfully applied to a space camera. After assembly, the coaxiality between the optical axis of the primary mirror and the optical axis of the secondary mirror is better than 0.02mm, the Angle between the optical axis is better than 10 ", and the wavefront of the primary and secondary mirror system is close to the optical design index. The assembly method presented in this paper provides a technical reference for the assembly of similar large aperture optical machine system. © 2021 SPIE
  Accession Number: 20220811682264
• Record 412 of
  
  Title:Evaluation of compression quality of space-borne interference hyperspectral image
  
  Author(s):Zhang, Xiaorong(1); Li, Siyuan(1); Hu, Bingliang(1); Liu, Xuebin(1); Yan, Qiangqiang(1); Li, Yun(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 11763  Issue:   DOI: 10.1117/12.2586561  Published: 2021  
  Abstract:The data acquired by the space-borne interference hyperspectral imager is a hybrid interferogram cube. For this kind of complicated data, there are many compression schemes for the on-board compression encoder. How to determine the optimal compression scheme and the optimal compression parameters under this compression scheme is crucial to recovering data. This paper proposes three compression schemes for space-borne interference hyperspectral images, which are mixed interferograms, pure interferograms, and fast views, respectively, and performs a compression evaluation. The peak signal-to-noise ratio of the recovered image, minimum quadratic error, and the spectral angle corresponding to the restored spectral curve are used as the measurement indicators to determine the optimal scheme and the optimal compression parameter configuration which are successfully applied to the development of the spectrometer. This paper establishes a scene-rich remote sensing interference hyperspectral image data source, quantitatively evaluates the impact of different compression ratios under different compression schemes, and changes in remote sensing image displacement, guides instrument design and parameter configuration, and lays a good foundation for the data application of space-borne interference hyperspectral images. © 2021 SPIE
  Accession Number: 20211410162042
• Record 413 of
  
  Title:High sensitivity FBG humidity sensor coated with graphene and polyimide films
  
  Author(s):Li, Ziwan(1,2); Dong, Bo(3); Chen, Enqing(1,2); Li, Yang(1,2); Zhao, Wei(1,2); Wang, Yishan(1,2); Gao, Cunxiao(1,2)
  Source: Optical Fiber Technology  Volume: 66  Issue:   DOI: 10.1016/j.yofte.2021.102635  Published: October 2021  
  Abstract:A high sensitivity FBG humidity sensor coated with polyimide and graphene films is proposed. The sensing probe is based on a fiber Bragg grating coated with an inner polyimide film and an outer graphene film. The sensor shows the high humidity sensitivity and experimental results show that its sensitivity is 1.80 times that of the sensor coated with only polyimide film. Within the humidity range of 30%–70%RH, its sensitivity reaches 19.8 pm/%RH and is almost 25 times that of the other lower sensitivity FBG humidity sensor. © 2021 Elsevier Inc.
  Accession Number: 20212910654389
• Record 414 of
  
  Title:Small-size streak tube with high edge spatial resolution
  
  Author(s):Tian, Liping(1); Shen, Lingbin(1); Li, Lili(2); Wang, Xing(2); Chen, Ping(2); Wang, Junfeng(2); Chen, Lin(1); Zhao, Wei(2); Tian, Jinshou(2)
  Source: Optik  Volume: 242  Issue:   DOI: 10.1016/j.ijleo.2021.166791  Published: September 2021  
  Abstract:A small-size streak tube with high spatial resolution over the entire working area is designed, manufactured and tested. The streak tube adopts curved photocathode and curved screen to improve the spatial resolution, especially at the edge area by decreasing the aberration. An accelerating slit electrode, instead of a mesh which limits the luminance gain of the tube, is employed next to the photocathode to improve the electrical resistance, reliability and the temporal resolution by increasing the electron acceleration field. The results in the numerical simulations show that the spatial resolution is 29 lp/mm @ MTF = 10 % over the whole effective photocathode area. The tested results show that the small-size streak tube can offer static spatial resolution as high as 20 lp/mm over the whole effective area. And, the maximum point of the static spatial resolution 25 lp/mm, is deviated away from the center of the photocathode. The experiment results indicate that the spatial resolution is higher than 23.4 lp/mm @ MTF = 10 %. The luminance gain can reach to 39.4 and the dimension of the streak tube is only Φ40 mm × 140 mm. Comparing with 5200 streak tube_XIOPM, we demonstrated that this small-size streak tube in our design not only possesses the compact size, but also obtain a much larger effective working area and much higher luminance gain. © 2021 Elsevier GmbH
  Accession Number: 20212410482956
• Record 415 of
  
  Title:Research on the properties of HfO2optical films prepared with APS assisted electron beam evaporation deposition
  
  Author(s):Pan, Yong-Gang(1); Liu, Zheng(1); Li, Mian(1); Liu, Wen-Cheng(1); Bai, Long(1); Zhang, Si-Bao(1); Luo, Chang-Xin(1); Zhang, Chun-Juan(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 11912  Issue:   DOI: 10.1117/12.2602069  Published: 2021  
  Abstract:HfO2 thin films are widely used in laser system because of its superior optical and mechanical properties, especially high laser induced damage threshold. In this paper, single-layer HfO2 thin films were prepared by APS plasma assisted electron beam evaporation deposition. The effects of oxygen charging of electron gun, baking temperature, discharge current of APS source and bias voltage of APS source on optical properties, surface roughness, standing wave electric filed and laser induced damage threshold of HfO2 thin films were studied by orthogonal experiment. Experiment and analysis results showed that the characteristics of HfO2 thin films are closely related to the oxygen charging of electron gun, baking temperature and APS assisted processing parameters. Especially, baking temperature, oxygen charging of electron gun and bias voltage of APS source have great influence on laser induced damage threshold. Through the analysis of experimental date, the optimal combination of process parameters for APS assisted electron beam evaporation of HfO2 optical films were obtained. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
  Accession Number: 20213510845105
• Record 416 of
  
  Title:Dual Mode High Speed Uncooled Short Wave Infrared Camera Based on FPGA
  
  Author(s):Liu, Qing(1); Wang, Huawei(1); Bian, He(1); Wang, Hua(1)
  Source: Journal of Physics: Conference Series  Volume: 1952  Issue: 3  DOI: 10.1088/1742-6596/1952/3/032042  Published: June 29, 2021  
  Abstract:This paper introduces a short-wave infrared camera logic design based on FPGA. The hardware design adopts the architecture of Sofradir Tecless SWIR detector SW640+Xilinx FPGA xc4vsx55, which has a dual working mode of 640 512 at 25 FPS and 64 48 at 4000 FPS. The function of high precision target tracking can be realized by high frequency capture of laser signal. In this design, the non-uniform correction coefficient table in SDRAM cache Flash is controlled by FPGA to correct the image of full resolution mode, and the table of 64 48 is cached by Bram in FPGA to achieve fast image correction and processing. The exposure time is controlled by the external synchronous signal, and the 14 bit precision image data are collected by four ADCs for restoration. The output data is processed by image bad point correction, non-uniform correction, median filtering, histogram equalization, and then the image is packaged and sent by the specified protocol. © Published under licence by IOP Publishing Ltd.
  Accession Number: 20212810609192
• Record 417 of
  
  Title:Synchronous detection of heavy metal ions in aqueous solution by gold nanoparticle surface-enhanced laser-induced breakdown spectroscopy
  
  Author(s):Yao, Yaqian(1,2); He, Fan(1,2); Lin, Qingyu(3); Tian, Yonghui(2,4); Zhang, Tianlong(4); Xu, Boping(5); Qi, Xinyuan(1); Duan, Yixiang(2,4)
  Source: Journal of Analytical Atomic Spectrometry  Volume: 36  Issue: 12  DOI: 10.1039/d1ja00310k  Published: December 2021  
  Abstract:Heavy metal ion-induced water pollution has become a severe environmental problem in the world. Although providing a powerful technique for multi-element detection, laser-induced breakdown spectroscopy (LIBS) suffers from insufficient sensitivity for detecting heavy metal ions in aqueous solution due to water splashing and surface ripples. In this work, a simple and sensitive method called gold nanoparticle (AuNP) surface-enhanced laser-induced breakdown spectroscopy (SELIBS) was proposed to detect trace or ultra-Trace heavy metal ions in aqueous solutions using a portable instrument. Firstly, the coulombic force allows the adhesion of negatively charged AuNPs and cationic amphiphilic solutions to capture heavy ions, thereby directly improving signal intensity. Interestingly, AuNP size-dependent signal enhancement was found in heavy metal ions through LIBS. To be specific, the signal intensity of Cu, Pb, and Cr increased by 9, 23, and 26 times, respectively, under the optimal AuNP size with a diameter of 13 nm compared to that of the pure target solution. Although the sizes of AuNPs did not affect the plasma temperature and electron density, the local electric field and coulombic force effectively enhanced the LIBS signal. Under optimized experimental conditions, the proposed method achieves sensitive detection of heavy metal ions of Cu, Pb, and Cr with low detection limits (LODs) of 5 ng mL-1, 22 ng mL-1, and 9 ng mL-1, respectively. Moreover, the recoveries of all analytical elements in environmental water samples were analyzed by the standard addition method. The recoveries were in the range of 92.70-100.19%, which further proves the feasibility and potential of surface-enhanced laser-induced breakdown spectroscopy of AuNPs in analyzing actual liquid samples. This journal is © The Royal Society of Chemistry.
  Accession Number: 20215011309085
• Record 418 of
  
  Title:Research on Auto-focusing Method Based on Pulse Coupled Neural Network
  
  Author(s):Chen, Taoyu(1); Wang, Huawei(1); Cao, Jianzhong(1)
  Source: Journal of Physics: Conference Series  Volume: 1848  Issue: 1  DOI: 10.1088/1742-6596/1848/1/012158  Published: April 13, 2021  
  Abstract:The key to automatic focusing method based on image processing is to construct a fast and accurate focus quality evaluation function. The method in this article introduces Pulse Coupled Neural Network processing. Using the characteristics of the network, through the enhanced image, the grayscale sum can be conveniently used to characterize clarity, thereby simplifying calculations and enhancing the real-time performance of focus control. © Published under licence by IOP Publishing Ltd.
  Accession Number: 20211710253695
• Record 419 of
  
  Title:Alignment control in off-Axis Gregorian system with reverse optimization method
  
  Author(s):Yin, Yamei(1); Fu, Xing(1); Lei, Yu(1); Cao, Mingqiang(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12069  Issue:   DOI: 10.1117/12.2606822  Published: 2021  
  Abstract:Off-Axis refractive system with the noticeable advantages such as high resolution, large view field and central obscuration removed, has been one of the powerful systems for space astronomical telescopes in recent years. However, misalignment errors and surface error of mirrors are significant especially in the alignment progress of off-Axis reflective telescope with large aperture. Computer aided assembling (CAA) jointly provide a robust misalignment correction method to ensure the accurate alignment of telescope. In this paper, system aberration of misalignment coaxial system with two mirrors is analyzed in detail, moreover, the off-Axis system is studied further, especially in the off-Axis Gregorian system. And the feasibility of correction values solution about off-Axis refractive system is discussed. Both the simulation and experiment results demonstrate the feasibility of the proposed alignment method and high accuracy has been achieved. In the testing off-Axis Gregorian system, the primary mirror is paraboloid with 1200 mm diameter, 210 mm off-Axis distance, and the second mirror is ellipsoid with off-Axis distance 129.0 mm, focal length 425 mm and 2125 mm, respectively. For the testing off-Axis Gregorian system, the RMS value of primary mirror and second mirror are 0.021 λ and 0.027 λ (λ = 0.6328 nm), and the testing optimization result of system wavefront aberration with RMS value is better than 0.058 λ is achieved. The reverse optimization method testing can achieve high-Accuracy measurement ability, which provides efficient and flexible way for the off axis refractive system from various types of elements with complex surfaces. © COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only.
  Accession Number: 20220211444608
• Record 420 of
  
  Title:Figure error of optical elements induced aberrations of optical system
  
  Author(s):Pang, Zhihai(1); He, Tianbin(1)
  Source: Proceedings of SPIE - The International Society for Optical Engineering  Volume: 12071  Issue:   DOI: 10.1117/12.2604752  Published: 2021  
  Abstract:The optical element's figure error can be express as Fringe Zernike polynomial and vector form, based on the vector wavefront aberration theory, the figure error of optical element induced aberration's characteristic of optical system has been analyses in this paper. The figure error on stop aperture affects all the field angles equally and induced the same type aberration as figure error. If the surface of optical element is not the pupil of optical system, the aberration observed in the focal plane is different from the figure error itself, it will not only induced the same type aberration as figure error but also induced lower order aberration in the optical system, the relationship between aberration and field of view is different and the location zero for the lower order aberration always reside at the center of the field of view. © COPYRIGHT SPIE.
  Accession Number: 20220811674432