Fabrication and Simulation of Large-Scale MEMS Deformable Mirror for Wave Front Active Control

Adaptive optics (AO) is a technology which improves the performance of optical systems by reducing the effects of rapidly changing optical distortion. Wave front active control by combining wave front sensor and MEMS deformable mirrors which made of polyimide thin film actuated by electrostatic force is one possible solution. Wave front sensor detects the image and aberration could be described with Zernike polynomials, and the distorted wave-front is corrected by deformable mirror. Combining these two technologies, we fabricate a large-scale MEMS deformable mirror with a 20mm diameter circular opening and 67 hexagonal actuation electrodes in this thesis. Moreover, we use commercial software, Ansys, to simulate the deformation behavior of the membrane with different electrodes applied and give some device parameter tuning for versatile application. We measure the maximum stoke is 39 um as 195 volts applied to 67 electrodes. Due to the large-scale of our thin membrane, resonant frequency is around 8 Hz. Besides, we also discuss some possible ways to improve device characteristics and we think deformable mirror has a good potential for wave front active control based on our experiment results.