大口径非圆形光学平面的五棱镜扫描检测技术研究

Optical testing of large optical flat mirror with non-circular pupil based on scanning pentaprism technology

为了解决非圆形大口径光学平面镜加工过程中的高精度检测问题,针对五棱镜扫描技术,使用一种基于多项式内积以及cholesky分解的非递归方法进行数据处理,同时编写了检测拟合程序,并结合工程实例,对30m望远镜(TMT),thirty meter telescope)项目的三镜(2.5m×3.5m椭圆形平面镜)进行了模拟检测的Monte-Carlo分析。分析结果表明,五棱镜扫描系统对TMT三镜低阶像差的检测精度可以达到30.6nm 5 rms,对power项、astigmatism项的检测精度分别达到9.6nm rms及13.7nmrms,能够完成大口径非圆形光学平面镜低像差的高精度检测。

In order to solve the difficulty in the optical testing for larg e non-circular flat mirrors,we use a non-recursive algorithm based on the inner products of polyn omials and the cholesky decomposition methods to complete data processing for the scanning pent aprism system （SPS）,and develop the corresponding testing data fitting software.Using the Mont e_Carlo technology,we analyze the feasibility for the SPS to test the thirty meter telescope （TMT） te rtiary mirror,which is an elliptical flat mirror with size of 2.5m×3.5m.The s imulation results show that the SPS could measure the low order aberrations of this mirror with root mean square（RMS） error of 30.6nm,especially the power RMS of 9.6nm and astigmatism of 13.7nm,which proves the suitability of S PS in testing low order aberrations of large non-circular pupil optical flat mirrors .