利用子孔径拼接法测量大口径凸面反射镜

在简要分析各种检测大口径凸球面方法优缺点的基础上，提出了利用子孔径测量凸面反射镜的新方法，利用干涉仪标准球面波前依次干涉测定大口径镜面上各个区域的相位分布，通过子孔径拼接算法即可求解得到镜面全口径面形信息。对该方法的基本原理和实现步骤进行了分析和研究，建立了大口径拼接检测算法数学模型，设计并研制了大口径反射镜拼接检验装置。结合实例对加工过程中的口径为300 mm的碳化硅凸面反射镜进行了9个子孔径的拼接干涉测量，并将检测结果与全口径面形测量结果进行对比，两种方法残差的PV值和RMS值分别为0.102 和0.009 (=632.8 nm)。

Large convex mirror measurement by subaperture stitching interferometry

On the basis of summing up conventional testing methods for convex mirror, a novel method for testing convex surfaces by subaperture stitching interferometry (SSI) was proposed. A sphere mirror is used as the reference surface, the phase distribution of each subaperture can be measured by the digital wavefront interferometer, and the full aperture surface map can be calculated by stitching several subapertures. The basic principle and theory of SSI were researched, and the stitching processing and prototype for testing convex spheres were devised and developed. A convex SiC sphere with the aperture of 300 mm was tested by SSI with 9 subapertures. For the validation, the sphere was also tested by large interferometer and beam expander, and the peak-valley(PV) and root-mean-square(RMS) residual errors between them were 0.102 λ and 0.009 λ, respectively(λ=632.8 nm).