结构函数在大口径光学系统评价中的应用

Application of structure function on large aperture optical system evaluation

为了降低大口径望远镜在研制和使用过程中的技术风险,将从结构函数的角度对大口径望远镜光机系统评价方法进行分析和研究。首先通过理论计算得出结构函数与光机系统评价的常用指标——斯特利尔比以及系统波像差均方根的关系,并对于结构函数的具体求解方法进行了讨论;然后对于低阶Zernike项对应的系统低频波像差以及Kolmogorov谱反演代表的高频系统波像差进行了分析,得出结构函数在不同的评价尺度下系统斯特利尔比的变化趋势。由于大气相干长度与系统结构函数有直接关系,且直接影响到大口径光学系统的使用效果,最后基于极大似然估计提出了一种大气相干长度估计方法。

In order to reduce the risk for development and using of large aperture telescope, structure function was discussed in this paper. Firstly, the relationship between structure function and Strehl ratio was gotten in theory, and the method for calculating structure function was founded. Then, after low order ones of Zernike polynomial were analyzed, simulating the low order disturbance, the Kolmogorov spectrum was used to simulate the high ones, getting the tendency of strehl ratio in different dimension. Because of the direct relationship between coherent length and structure function, and the influence of the coherent length on the performance of the large aperture optical system, a method for evaluating the coherent length was proposed based on maximum likelihood method.