本文基于 Schupmann消色差理论, 介绍了一种离轴四反射镜衍射成像光学系统设计方法。设计了口径 1 m、F数为 8、视场 0.12°、波段 582.8 nm～682.8 nm的离轴四反射镜衍射成像光学系统。设计结果表明, 该光学系统的色差得到有效校正, 系统调制传递函数 (MTF)在 50 lp/mm范围内优于 0.53, 弥散斑半径的均方根值小于艾里斑半径, 成像质量接近衍射极限。分析了平面衍射物镜和曲面衍射校正镜可分别采用二元光刻工艺和金刚石车削技术制作的原因。对设计结构进行公差分析, 确定公差误差主要来源于中继反射镜的倾斜角度, 为装调过程提供指导。设计的系统为宽波段、高像质的反射式衍射成像光学系统发展提供了参考。

According to the Schupmann’s achromatic theory, a calculation method of off-axis four-mirror diffractive imaging optical system is introduced. By using the method, an optical system which has an aperture of 1 m, F-number of 8, full field of view of 0.12°, waveband of 582.8 nm～682.8 nm is designed. The results show that the chromatic aberration is corrected effectively. The modulation transfer function (MTF) is more than 0.53 in the range of 50 lp/mm, and the RMS radius of diffusion spot is less than the airy radius. It demonstrates that the image quality of this system is close to the diffraction limit. It is analyzed that the processing of diffractive primary lens and diffrac-tive correct mirror can be realized by traditional lithography and diamond turning, respectively. Monte-Carlo simula-tion of tolerance analysis is carried out, it determined that the tolerance error mainly originates from the tilt angle of relay mirror, which provides guidance for the process of assembling and adjusting. This system has the advantages of broadband, high image quality, which can provide references for the development of reflective diffractive imaging optical system.