【摘要】 人造信标[即激光导引星(LGS)]概念的提出解决了自适应光学系统(AO)的湍流参考源问题,同时也带来了不可避免的非等晕误差。利用新研制的自然星哈特曼传感器(HS)与信标哈特曼传感器在望远镜系统上实现了自然参考星与瑞利信标的湍流波前时间同步测量,从而对不同模式(包括纯聚焦模式、角度与聚焦相耦合模式)瑞利信标的非等晕误差进行了定量研究。通过对测量所得自然星与瑞利信标湍流波前的泽尼克模式像差分解及对比分析发现,不同高度瑞利信标波前与自然星波前的各阶泽尼克模式时间互相关性,随其像差阶数的增加而振荡下降。相比于自然星波前的各阶像差模式方差分布,不同模式瑞利信标的非等晕误差均随像差模式阶数的增加而逐渐增大,即信标的非等晕误差对高阶像差更加敏感。最后,通过对不同实验模式非等晕误差所致目标校正光波质量影响的分析计算,并将其与前期信标非等晕问题的数值建模相结合,获得了不同非等晕机制下理论与实验相互映证的结果。该实验研究结果的取得,增强了对瑞利信标非等晕问题的感性认识。更多还原

【Abstract】 The atmospheric turbulence probing source of adaptive optics(AO)is proposed by the promotion of the artificial beacon,namely laser guide star(LGS);however the unavoidable anisoplanatic error it brings can degrade the performance of AO system.By using new developed natural star Hartmann-Shack(HS)sensor and artificial beacon HS sensor,the temporal synchronized turbulence-induced wavefronts measurement is achieved on telescope system for natural star and Rayleigh-LGS.Accordingly our experimental investigation of Rayleigh-LGS anisoplanatism effect with different LGS-modes(including focal anisoplanatism and angular &focal anisoplanatism)is presented.The experimental results show that,increasing the Zernike order of turbulence-distorted wavefront aberration makes the temporal correlation for corresponding aberration mode between natural star and Rayleigh-LGS with different altitudes present an oscillation downward trend.Comparing with the Zernike variances of natural star wavefront,the modal anisoplanatic error of Rayleigh-LGS increases with the increase of the Zernike order,which is greatly sensitive to high-order aberration.At last the comparisons of our former numerical-modeling and experimental-measuring results of different-mode Rayleigh-LGS anisoplanatic error′s impact on the corrected light-wave quality are analyzed,and both of the results are in good agreement.This investigation is a useful promotion of our perceptive knowledge of Rayleigh-LGS anisoplanatic effect in turbulence probing.更多还原