Laboratory test of MEMS based astronomical adaptive optics

We built a simple Adaptive Optics (AO) system at laboratory. This AO system is a step toward developing AO system for astronomical use. In this step, the AO system consists of He-Ne laser as a artificial light source, wavefront sensor, MEMS (Micro electro mechanical system) type deformable mirror and several lenses. MEMS deformable mirror allows the compact system at low cost and the only several mm sized collimated beam. We made Shack-Hartmann wavefront sensor using a lenslet array and a fast frame CCD. Its performance is verified using an artificial phase disturber and noting the movement of spot images by the lenslet array. The frame rate of the driving software is about 70 fps, depending on the control parameters. The characteristics of MEMS deformable mirror was measured which includes the voltage-to-deflection relation, influence function, and cross-talk. The total system is operated under closed-loop control for the artificial phase disturber and the wavefront is found to be compensated successfully.