子孔径合成光学成像系统像质评价研究

子孔径合成光学成像系统的出瞳波前是离散的，需要同时引入波象差和衍射光学理论，拟合最佳高斯参考球面，计算出瞳波前和波象差，并通过对像面的衍射积分，评估系统像质。对比了两种像质评估的方法，其一是直接利用干涉仪实测获得的整体出瞳波面参数拟合Zernike多项式衍射直接积分法计算像面复振幅分布，其二是对子出瞳波面衍射直接积分在像面的复振幅的叠加。设计并制造了一个三子镜合成的成像光学系统，在此基础上用ZYGO GPI XP干涉仪验证并对比了使用两种方法的对像质计算的特点。结果表明，子出瞳波面直接衍射积分叠加法的精度更高，但计算量大；在衍射限附近，前者的拟合精度也能满足像质的定性评估要求，且计算量较小。

Imaging quality of segmented mirror synthetic aperture optics

Exit pupil wavefront of segmented mirror synthetic aperture optics is discrete, and much different from traditional systems’. Theory of wave aberration and diffraction optics should be introduced to evaluate imaging quality simultaneously. By using the diffraction integral, two methods are used to evaluate imaging quality, which one is fit the exit pupil wavefront to Zernike polynomial directly and calculate the complex amplitude distribution, and the other way is calculate the complex amplitude distribution of each sub-exit-pupil individually, and overlap them in image plane. A segmented mirror system with three sub-mirrors primary is built, and the wavefront is obtained by ZYGO GPI interferometer, include overall exit pupil wavefront and each sub-exit-pupil wavefront. The two methods are compared and the result shows that the latter way is more precision but complex; on the other hand, the former way can satisfy the required precision and more simple, when the system exit pupil wavefront is near the diffraction limit.