影响函数是分析双压电片变形反射镜像差校正能力的重要参量,通过建立有限元模型预测实际器件的影响函数,以有限元模型的不断优化替代实际器件的尝试性改进,可以减小构造的盲目性,从而节约研发成本,缩短双压电片变形镜的实用化进程。采用Veeco干涉仪测量了20单元双压电片变形反射镜的影响函数,同时建立有限元模型进行了相应计算,并将计算结果与实际器件的测量数据进行了对比分析。结果表明,相对于实测数据而言,有限元模型计算得出的影响函数在量值上略有偏小,但其形状和峰值位置与测量数据一致性好,两者对前35项泽尼克像差的拟合曲线也基本吻合,各项拟合误差系数之差皆小于0.1。这说明通过不断改进有限元模型实现对实际器件的优化设计是切实可行的。

Influence function is a key parameter to evaluate the capability of bimorph deformable mirrors in correcting aberrations. Influence functions of a 20-element bimorph deformable mirror are measured by Veeco interferometer and simulated by a finite element model. Compared with the measured data, simulated results come out a little smaller. But they are consistent in both shape and the location of peak. And the finite element model can predict the correction on 1～35 Zernike aberrations of the 20-element bimorph deformable mirror correctly, with errors smaller than 0.1. It is feasible to improve the bimorph deformable mirror by optimization of its finite element model.