低温真空环境光学系统波像差测试方法

Measurement method of the wave front aberration of optical system in cryogenic vacuum environment

为了能够预知空间低温光学系统成像质量,提出了一种高精度测试低温真空环境下F数小、后截距短的光学系统波像差的方法。首先,分析设计测试光路,对低温光学系统、干涉仪以及平面镜等进行布局,为波像差测试做好准备工作;然后,对低温真空标准透镜、标准平面镜、窗口玻璃等关键部件进行分析与设计,测试时作为系统误差项扣除;最后,调试测试光路,分别得到常温常压和低温真空环境(低温温度为100 K,压强为1×10^(-4) Pa)下光学系统波像差。通过精度验证实验表明,测量值与标准值偏差为0.010λ(λ=632.8 nm),差别很小,证明了该测试方法的可行性。解决了光学遥感系统特别是F数小、后截距短在低温真空环境下波像差难以高精度测试或无法测试的难题。

In order to predict the imaging quality of space cryogenic optical system, a method of high accuracy measuring the wave front aberration of the optical system with low F number and short back focal in cryogenic vacuum environment was presented. Firstly, the optical path was designed. The layout of cryogenic optical system, interferometer and flat mirror were prepared for wave front aberration testing.Then, the key components such as cryogenic vacuum standard lens, standard flat mirror and atmospheric window glass were analyzed and designed. The testing wave front aberration was removed as a system error term. Finally, the wave front aberrations of normal pressure and temperature and cryogenic vacuum environment（Temperature： 100 K, Pressure： 1 ×10^（-4） Pa） were obtained by debugging the optical path. The accuracy test showed that the deviation between the measured value and the standard value was 0.010λ（λ=632.8 nm）, and the difference was very small, which proved the feasibility of the test method. The wave front aberration difference between the two stages was small. This method solved the difficult problem of the cryogenic vacuum optical system wave front aberration testing with low F number and short back focal in the cryogenic vacuum environment, which couldn′t be accurately tested or even tested.