A self-correction method for deformable mirror with thermal deformation

In high-power laser systems, temperature gradient distribution arises in optical components irradiated by a high-power continuous wave (CW) laser, leading to the thermal deformation of the optical components and further the degradation of the beam quality. The deformable mirrors (DMs) are commonly used to improve the beam quality, but the thermal deformation of the DM irradiated by the high-power CW laser also exist and is more complex than that of conventional reflecting mirrors, resulting in high-frequency distortion of the corrected wavefront. In this paper, a finite element model for the DM with high reflectivity films is built up, and then the thermal deformation of the DM is simulated and analyzed. According to the deformable feature of the DM, a self-correction method is proposed, i.e., the DM corrects its thermal deformation by itself, and a self-correction function is established to control the actuators of the DM. Finally, effects of the self-correction method on beam quality are discussed quantitatively. Results show that the self-correction method can compensate the thermal deformation distribution of the DM and even constrain the generation of high-frequency distortion. Consequently, the self-correction method is feasible to compensate the thermal deformation of the DM, and further improves the beam quality.