为了研究高功率连续激光辐照过程中快反镜的热性能变化问题, 文中利用多物理场仿真分析软件建立了融凝石英(fused silica)、微晶(zerodur)、碳化硅(SiC)三种材料制作的快反镜传热学和结构力学耦合非稳态模型, 通过泽尼克多项式算法对高功率激光辐照快反镜热应力下的光学波前进行拟合。研究结果表明: 在同等激光功率辐照条件下, 微晶材料制作的快反镜温升最小, 形变最小。根据仿真结果优选微晶作为快反镜镜体材料, 基于泽尼克多项式对快反镜波前热畸变进行仿真分析, 计算得到波前热像差以活塞、球差、离焦等为主导, 可为波前校正工程应用提供理论参考。

In order to study the thermal characteristic of fast steering mirror during the working process of high power CW laser, a time-dependent fast steering mirror model coupled with heat transfer and structure mechanic was established to calculate the distribution of temperature, thermal deformation and thermal stress by finite element software, and the material was fused silica, zerodur and sic respectively. The wave front of fast steering mirror was fitted by Zernike polynomial algorithms. The results indicate that under the same laser power irradiation conditions, the minimum temperature rising and thermal distortion of the three material is zerodur. By comparison, zerodur material is optimized as fast steering mirror, and its dominant thermal aberration are piston, spherical aberration and defocus, which can provide wavefront correction to theoretical reference in the field of engineering application.