Study on the Effect of Laser Irradiation on High-order Aberrations of Deformable Mirror by FEM

In order to analyze the influence of laser irradiation on high-order aberrations of the deformed mirror, the finite element model of a 37-element deformable mirror was built. The deformation and high-order aberrations were calculated after applying the laser irradiation to the mirror. Based on the results, we found the high-order aberrations became larger and larger while the thickness of the mirror decreasing. The high-order aberration presented a honeycomb shape of the piezoelectric actuator when the mirror thickness is 1 mm. The PV decreased from 0.128 mu m to 0.104 mu m when the mirror got thicker from 1 mm to 3 mm, and the corresponding removed low-order Zernike coefficient residual error was reduced from 0.107 mu m to 0.0504 mu m. The high-order aberrations of the deformed mirror were very little when the mirror surface thickness was 3 mm. The results have practical engineering application for the design of deformable mirrors in future laser systems.