超大口径平面反射镜的光学检测(特邀)

Optical testing of the super-large plane mirror(Invited)

在简要总结了各种检测大口径反射镜难点的基础上,为了实现30 m望远镜(TMT)超大口径第三反射镜的高精度检测,提出了一种融合五棱镜扫描技术和子孔径拼接测试技术的新方法。大口径反射镜分阶段依次进行了五棱镜扫描测试和子孔径拼接检测,对该技术的基本原理和基础理论进行了分析和研究,制定了检测30 m望远镜第三反射镜(口径为3.5 m×2.5 m)的方案,对其测试流程、五棱镜设计、五棱镜扫描像差拟合、拼接最优化算法等进行了详细分析,并对30 m望远镜第三反射镜的原理镜进行了实验验证,其最终拼接检测面形的均方根值(RMS)和斜率均方根值(slopeRMS)分别为28.676 nm和0.97μrad。

On the basis of summing up the difficulties of testing large flat mirror,for the sake of testing superlarge surface especially for the tertiary mirror of Thirty Meter Telescope(TMT-M3) with precise method,a new technology syncretized pentaprism scanning method and Subaperture Stitching Interferometry(SSI) was proposed.The large mirror was tested by pentaprism scanning and SSI successively,the basic principle of the metrology was introduced and researched,and a reasonable optical testing project of TMT-M3 with the aperture of 3.5 m×2.5 m was made,the flow chart,pentaprism design,aberration fitting of pentaprism scanning,and the optimum stitching algorithm were analyzed particularly.And a prototype of TMT-M3 was developed for experimental verification.The Root Mean Square(RMS) and slope Root Mean Square(slopeRMS) values are28.676 nm and 0.97 μrad,respectively.