透镜自重变形引起波像差的有限元分析

在用大口径、长焦距平行光管模拟激光远场特性时，其光组透镜在重力作用下的变形不能忽略，为了分析对出射光束质量的影响，采用有限元分析软件“ANSYS”建立了平行光管光组中声400mm平凸透镜的有限元模型，给出一种分析透镜轴向变形引起的波像差的方法，在不同工况下，计算了平凸透镜在重力作用下轴向变形的峰谷值和均方根值，对轴向变形量均方根值最小工况画出了透镜表面变形的等值线图，计算了声350mm通光口径内的波像差峰谷值和均方根值，对平行光管光组的波像差做出估计，验证了设计的合理性。

When collimator with big diameter and long focal length is used to simulate laser far-field character, the deformation of its lens under gravity cannot be ignored. To analyze the effect, finite element analysis software ANSYS is adopted to simulate a ??400 mm plano-convex lens from a collimator, and a method is presented to analyse wavefront error caused by axial deformation of lens, P-V and RMS values of axial deformations under gravity are computed in different cases, the contours of lens surface are plotted when RMS values of axial deformations is the smallest, the P-V and RMS wavefront error in ??350 mm are also calculated, finally the wavefront error of lenses is estimated in optimal case, and the rationality of collimator design is validated.