子孔径拼接干涉测量一大口径双曲面(英文)

为了无需辅助元件就能够实现对大口径非球面的检测,将子孔径拼接技术与干涉技术相结合,提出了一种利用子孔径拼接干涉检测非球面的新方法.分析了该技术的基本原理,并基于齐次坐标变换、最小二乘拟合建立了一种综合优化的拼接模型,在此基础上初步设计和搭建了子孔径拼接干涉检测装备.利用该方法对一口径为350 mm的双曲面进行了5个子孔径的拼接检测,得到拼接后的全口径面形误差的PV值为0.319λ,RMS值为0.044λ(=632.8 nm).为了对比和验证,对该非球面进行了零位补偿检测,两种方法测量所得的全口径面形分布是一致的,其PV值和RMS值的偏差分别为0.032λ和0.004λ.实验结果表明:该数学模型和拼接算法是准确可行的,从而提供了一种非零补偿测试大口径非球面的手段.

Subaperture stitching interferometry for testing a large hyperboloid

In order to test large aspheric surfaces without the aid of null optics, a novel method called subaperture stitching interferometry (SSI) is presented. The synthetical optimization stitching model are established based on homogeneous oordinate's transform and simultaneous least-squares fitting. A prototype of testing large aspheres is developed by the stitching method. The experiment of testing a hyperboloid with SSI is carried out. The PV and RMS of the surface are 0.319λ and 0.044λ ( is 632.8 nm) respectively when five subapertures are stitched together. For comparison and validation, the asphere is also measured by null testing. It is shown that the two testing results consist with each other, PV and RMS error are 0.032λ and 0.004λ respectively. Thus, it can be concluded that the algorithm and model of the SSI technology are feasible for the testing of large aspheric surfaces, which provides the probability of testing the mirror with large aperture and asphericity in non-null configuration.