设计了一款口径为30.48 cm高精度斐索激光干涉仪参考镜,其F数为0.82,参考面半径为224.99 mm。所设计的参考镜其透射波前峰谷值为0.095 λ,均方根值为0.028 λ,透射波前斜率最大值为11 μrad。理论分析了参考镜的回程误差对面形检测精度的影响,其最大值为0.29 nm。利用Zemax光学设计软件对参考镜进行了仿真分析,仿真与实验结果表明,该标准镜头可满足精度1 nm的元件面形检测需求。

A high-precision reference spherical lens is designed. The F number of the lens is 0.82. The wavefront PV value is 0.09 λ and RMS value is 0.028 λ. The slope of wavefront is 11 μrad. We calculate the retrace error of the reference spherical lens. The maximum of retrace error is 0.29 nm. A part of surface is measured with the reference spherical lens. The results show that precision of 1 nm can be reached.