YNAO OpenIR  > 应用天文研究组
自适应光学系统的激光导引星研究
Alternative TitleResearch on Techniques of Laser Guide Star for
周钰
Subtype博士
Thesis Advisor熊耀恒
2009
Degree Grantor中国科学院研究生院(云南天文台)
Place of Conferral北京
Degree Discipline天体测量与天体力学
Keyword激光导引星 聚焦非等晕性 活塞效应 激光导引星波前倾斜
Abstract随着自适应光学技术的发展,当观测暗目标时,若其本身不能够提供波前探测信息,等晕区内也没有足够强度的信标,那就使得自适应光学系统的能力受到了很大的限制,这时激光导引星就显得尤为重要。 本文首先介绍了激光导引星的产生背景和发展,在介绍了大气湍流和激光导引星基本原理之后,针对大气湍流对上行激光传输的光斑扩展问题进行研究。当光束在湍流大气中传输时,由于大气折射率的随机起伏,导致了光束波前相位的畸变,在经过一定的传输后,波束将产生扩展。作者将基于激光束在大气湍流传播理论,分析研究光斑扩展问题。 本文采用湍流探测配置的孔径滤波函数推导剩余波前畸变方差。作者推导了在天文干涉仪观测暗目标时,利用参考光束对测量光束由Piston引起的相位非等晕性误差。同时,针对激光导引星聚焦非等晕性的误差,特别是对于瑞利导星误差较大这一问题,作者采用投射多重导星的方法减小聚焦非等晕性误差。文中详细的研究了利用多重导星减小聚焦非等晕性误差以及多重导星方案存在的问题。根据得到的研究结果,对以后自适应光学系统的进一步发展都具有非常重要的指导意义。 本文对近年来各国科学家提出的波前倾斜探测方法(多色导星方法,辅助望远镜方法,辅助激光照明方法等)进行了详细的介绍,结合1.2米自适应光学系统的实际参数,得出当采用激光辅照明方法时辅助激光照明装置发射口径大小。 本文从1.2米激光导引星自适应光学系统工程设计方面出发,结合所需导星亮度或回波光子密度具体分析计算了激光器能量;作者从系统的角度,研究了共孔径法和分孔径法发射和接收信标系统,针对共孔径法杂散光对探测器造成的严重影响,作者设计了一种新型的转盘式机械快门装置彻底对探测器进行保护,从而使得自适应光学系统可以正常工作。
Other AbstractAdaptive Optics(AO) technology will be limited by the beacon or guide star problem when the object that is observated couldn’t provide real-time wavefront information, or there is no bright enough beacon within the isoplanatic field. Therefore, it is important to use artificial guide star, that is LGS(Laser Guide Star). In this dissertation, laser guide star background and development are introduced first, Second , after an introduction of the basic concepts about turbulence and laser guide star, based on laser beam propagation in the turbulence theory , the laser beacon expander problem has been analyzed by the author. Based on the filter function of the atmospheric turbulence sensing geometry, the variances of the residual wave front distortion resulting from focal anisoplanatism were derived. The analysis of results shown that focal anisoplanatism error for Rayleigh laser guide star was very severity. This error would eliminated by use of multiple laser guide stars. In this paper, author investigated the residual wave front error according to use of laser guide stars. At the same time, when using adaptive optics system astronomical optical interferometer to observe faint astronomical object, the differential piston angular anisoplanatism was derived by the author first time. Most of researcher have proposed the concept to detect the tip-tilt information from laser guide star, such as polychromatic LGS , auxiliary telescope, auxiliary laser ,et al.. In the following of this paper, author will combine 1.2 m telescope adaptive optics system to put forward a scheme how to retrieve the absolute tip-tilt. The project diameter, the distance between laser projector and telescope, all of parameters were investigated in detail. According to returned signal level and guide star spot size for laser guide star, laser pulse eneney, sampling depth were investigated in detail. Based on the technology of LGS launched and received in co-aperture, author has designed a new form of a fast mechanical shutter for protect wavefront sensor damage by scattered light.
Subject Area天文学
Pages84
Language中文
Document Type学位论文
Identifierhttp://ir.ynao.ac.cn/handle/114a53/7347
Collection应用天文研究组
Affiliation中国科学院云南天文台
First Author AffilicationYunnan Observatories, Chinese Academy of Sciences
Recommended Citation
GB/T 7714
周钰. 自适应光学系统的激光导引星研究[D]. 北京. 中国科学院研究生院(云南天文台),2009.
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