近年来, 大口径、大非球面度、快焦比、高次非球面光学元件在天文光学、空间光学和地基空间目标探测与识别等领域得到了越来越广泛的应用。目前对此类光学元件的检测一般采用零位补偿法或消回程误差的非零位检测法。其中消回程误差的非零位补偿法处理过程复杂, 缺乏检测直观性, 且测量精度无法保证, 故在针对一些面形精度要求非常高的镜面时并不适用。以口径为1020 mm、焦比为1/0.5、非球面度为1.8 mm、高次项达6次的凹高次非球面反射镜检测为研究基础, 提出了分阶段设计零位补偿检验光路的新思路, 以满足此类镜面在粗抛、精抛、干涉仪检测等不同研制与检验阶段的需求。最终检测面形精度达到了λ/50。

In recent years, the optical element with large diameter, large asphericity, fast focal ratio, high-order aspheric has been used in astronomical optics, space optics and space target detection and recognition with ground-based systems and other fields more and more widely. At present we commonly use null lens testing system or partial compensation system with eliminating return error process to test such optical elements. Among them, partial compensation system with eliminating return error process is complex and lack of testing intuitiveness, and the measurement accuracy cannot be guaranteed. Therefore, in the testing of some mirror with very high surface error precision requirement, this method is not applicable. Base on the test of concave high-order aspherical mirror with diameter of 1020 mm, coke ratio of 1/0.5, aspherical degree of 1.8 mm, high-order term of 6, an idea to design zero compensation testing light path by stages is proposed, which can satisfy the requirement of different stages of developing and testing such as rough polishing, fine polishing, interferometer testing. Final, its surface accuracy achieves λ/50.