Simulation and compensation of wavefront aberration caused by deformable mirror thermal deformation
The thermo-mechanical model of the deformable mirror based on ANSYS multiphysics is provided and calculated. High energy laser radiation results in a mirror deformation of about 0.9 m. Therefore, according to the characteristic distribution of the thermally-induced deformation, a compensation method is proposed. The compensation mirror, placed in the optical path after the deformable mirror, is composed of a thin mirror and some restriction parts. By contrast with the poles of the deformable mirror, the restriction parts of the compensation mirror are installed in a staggered order. Three types of compensation mirrors with different shapes of restriction parts are calculated. The results show that the values of the thermal deformation reduce to 0.35 m, 0.32 m and 0.40 m. Using the BPF (beam propagation factor) to evaluate the compensation effect, the results indicate that the BPF value increases from 0.906 to 0.966, 0.971 and 0.957. Further calculations show that the size of the restriction parts has little effect on the compensation effect.