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题名	自适应光学的激光导引星及微光波前探测技术
作者	沈锋
学位类别	博士
答辩日期	2002
授予单位	中国科学院上海光学精密机械研究所
导师	姜文汉
关键词	自适应光学 激光导引星 波前传感器 微光探测技术
其他题名	Technologies of Laser guide star (LGS) and low level light wavefront sensing for adaptive optics
中文摘要	自适应光学系统实时校正大气动态波前畸变,使光学系统能随时适应外界环境的变化,始终保持系统最优工作状态.自适应光学技术的进一步发展,受到信标技术和微光波前探测技术的很大限制,合适的信标以及相应的微光波前探测技术逐渐成为自适应光学系统进一步发展的瓶颈.该文针对这两大问题进行了探索性的研究,旨在研究微光波前探测技术以及与之紧密联系的激光导星技术的理论和应用特性.该文根据国家高技术计划863-308主题的迫切需要,研究了采用瑞利激光导引星的自适应光学系统的工程实现问题.在大气湍流波前探测技术的研究方面,该文首先对常规的哈特曼—夏克波前传感器的特点和探测精度进行了分析,通过对哈特曼—夏克波前传感器的噪声特性的分析,提出了提高其探测精度的阈值方法,分析了背景噪声对质心探测的系统误差和随机起伏方差的影响,并给出了解析模型.
英文摘要	Adaptive optics (AO) is the technology for correcting random optical wavefront induced by atmospheric turbulence in real time. Further development of AO technology will be limited by the laser beacon technology and the low level light wavefront sensing, appropriate beacon and corresponding wavefront sensing will be the "bottle-neck" of the functional works of AO system. In this dissertation, profound researches are carried out aiming at these two problems, and the purpose is to study the theoretical and applied characteristics. After introducing the basic concepts about turbulence and AO technology, the key problem of laser beacon-modal decomposition of anisoplanatic errors-is studied. Based on Zernike polynomials, the statistical correlation of random wavefronts between LGS and object are researched. In a creative way, I unified the focus anisoplanatism and angular anisoplanatism, and presented the viewpoint that is different anisoplanatic error for different aberration mode, and the mathematical expressions for modal decomposition of anisoplanatic errors are given. The analytical relationships and corresponding analysis for modal anisoplanatism of planar and spherical wave are" given out under three configurations about LGS and object based on rational small scale simplification. Particularly I investigated the modal anisoplanatism of Rayleigh LGS and Na LGS which are intensively used in astronomical adaptive optics. It is shown that anisoplanatic modal error for 90km height Na LGS is most less than that for Rayleigh LGS when no angular deviation between beacon and object, but is more sensitive of angular deviation. According to the demand of National High Technology Program 863-308 subject item, how to realize LGS adaptive optics system functionally is studied. The pulse energy, sampling depth, beam quality, project system, closed loop system, and the interface with adaptive optics are investigated in detail. One viewpoint that there exists an optimal aperture size of project system is set forth rationally. In the LGS system, one tilt control subsystem is constructed to stabilize the image of beacon. The low level light wavefront sensing is always companied with beacon problem. The characteristics and measurement accuracy of normal Shack-Hartmann wavefront sensor are analyzed, and one new method for improving its accuracy is put forward, which is setting a threshold level in processing centroid of Hartmann spots, and the theoretical analysis and experimental results are presented. The measurement of turbulent random wavefront with Shack-Hartmann wavefront sensor under real atmosphere, and the transferring characteristics of detecting noise in AO system are also researched. The optical characteristics of ICCD wavefront sensor are researched in emphasis, which include special point spreading, statistical character of single photon multiplication and gain fluctuation. One concept of gain fluctuation factor is put forward to describe Image Intensifier quality. The signal transfer and noise transfer modals are researched, and their expressions are given out analytically. To our knowledge, signal induced background noise of Image Intensifier (SIB) is first investigated. And one new method to reduce SIB and improve detecting accuracy of ICCD wavefront sensor is given out, which can be computed in real time.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15404]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	沈锋. 自适应光学的激光导引星及微光波前探测技术[D]. 中国科学院上海光学精密机械研究所. 2002.

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