自适应光学系统的模式法数值模拟

建立了利用模式法笃自适应光学系统进行数值模拟的理论模型，编制了计算程序，并与激光大气传输计算程序衔接起来，进行了大量数值模拟计算。首次发现：存在泽尼特多项式展开的最佳项数。大于一定项数的展开式的效果迅速变坏，竖排和斜排经特面式展开有类似的结果。文献中认为可以采用的１５项经特多项式展开的效果不好，最佳项数随着横向风速的增加而减小，在风速较大时最佳项数下的模范地结果稍好于直接斜率控制法的结果。

Numerical Simulation of An Adaptive Optics System by Means of Modal Wavefront Reconstruction

A theoretical model of numerical simulation of an adaptive optics (AO) system by modal wavefront reconstruction (i.e. by means of the Zernike polynomials expansion) is presented and the corresponding computer program is compiled. The AO computer program is combined with our simulation computational program of atmospheric propagation of laser beam to carry out a lot of simulation computations. It is found for the first time that there is an optimum term number of Zernike polynomials expansion. When the term number of Zernike polynomials expansion is higher than a certain value, results become worse very quickly. Zernike polynomials expansions of vertical arrangement and declined arrangement can give quite similar results. 15 terms of Zernike polynomials expansion which is thought usable in the wavefront reconstruction in literature, in fact can not give a correct result. The optimum term number gets lower as transverse wind speed is larger and the results of AO phase compensation by means of the model wavefront reconstruction with optmium term number are slightly better than those by means of the direct wavefront gradient control method.