Stochastic parallel gradient descent based adaptive optics used for a high contrast imaging coronagraph

作     者：Bing Dong De-Qing Ren Xi Zhang Bing Dong1,De-Qing Ren1,2 and Xi Zhang2 1 Physics & Astronomy Department,California State University Northridge,CA,91330-8268,USA2 National Astronomical Observatories/Nanjing Institute of Astronomical Optics & Technology,Chinese Academy of Sciences,Nanjing,210042,China

作者机构：Physics ＆ Astronomy Department California State University Northridge CA 91330-8268 USA National Astronomical Observatories/Nanjing Institute of Astronomical Optics ＆ Technology Chinese Academy of Sciences Nanjing 210042 China 

出 版 物：《Research in Astronomy and Astrophysics》 (天文和天体物理学研究（英文版）)

年 卷 期：2011年第11卷第8期

页      面：997-1002页

核心收录：

学科分类：12[管理学] 0709[理学-地质学] 07[理学] 08[工学] 1201[管理学-管理科学与工程(可授管理学、工学学位)] 070207[理学-光学] 081104[工学-模式识别与智能系统] 0708[理学-地球物理学] 0835[工学-软件工程] 0825[工学-航空宇航科学与技术] 0704[理学-天文学] 0803[工学-光学工程] 0811[工学-控制科学与工程] 0812[工学-计算机科学与技术（可授工学、理学学位）] 0702[理学-物理学] 

基　　金：Supported by the National Natural Science Foundation of China(Grant Nos. 10873024 and 11003031) supported by the National Science Foundation under Grant ATM-0841440 

主　　题：instrumentation: adaptive optics -- methods: laboratory -- techniques: image processing coronagraph 

摘      要：An adaptive optics （AO） system based on a stochastic parallel gradient descent （SPGD） algorithm is proposed to reduce the speckle noises in the optical system of a stellar coronagraph in order to further improve the contrast. The principle of the SPGD algorithm is described briefly and a metric suitable for point source imaging optimization is given. The feasibility and good performance of the SPGD algorithm is demonstrated by an experimental system featured with a 140-actuator deformable mirror and a Hartrnann-Shark wavefront sensor. Then the SPGD based AO is applied to a liquid crystal array （LCA） based coronagraph to improve the contrast. The LCA can modulate the incoming light to generate a pupil apodization mask of any pattern. A circular stepped pattern is used in our preliminary experiment and the image contrast shows improvement from 10^-3 to 10^-4.5 at an angular distance of 2A/D after being corrected by SPGD based AO.