拼接镜主动光学中子镜曲率半径偏差分析

摘要

拼接镜主动光学以完全相同的小口径反射镜为基础进行镜面拼接，使其共焦和共相，等效得到相应的大口径反射镜，并使其达到衍射极限成像。在各个子镜的拼接过程中，曲率半径不一致直接导致系统的成像性能受到较大影响。以3片子镜组成的拼接镜主动光学为基础，对子镜间曲率半径的偏差进行了分析。其中子镜为对角线长为346.42 mm的正六边形球面反射镜，等效单片反射镜口径为634 mm，经过分析得到子镜之间曲率半径偏差应小于±0.02 mm，此时拼接镜成像分辨力为0.309″，斯特涅尔比大于0.8，达到衍射极限。%Active optics with segmented mirror is based on some completely same small mirrors, which will be co-focus and co-phase, and then it can achieve the diffractive limited image of the large aperture mirror. In the process of segment, the curvature radius disagreement of these small mirrors would influence the system image quality directly. So, the paper tried to analyze this departure and give some tolerances. There are three small hexagon spherical mirrors whose side length is 300 mmand the aperture of equivalent mirror is 634 mm. Through analysis the radius departure of every small mirror is less than ±0.02 mm, the image resolution of segmented mirror is 0.309″, strehl ratio is larger than 0.8.