MEMS Deformable Mirrors for Adaptive Optics Actuated by Piezoelectric PZT Films

Abstract

The piezoelectric MEMS deformable mirrors for adaptive optics have been developed to realize low voltage and large stroke deformable mirrors. The PZT film was deposited on a Pt-coated silicon-on-insulator (SOI) substrate and the 19 segmented electrodes were prepared on it. The circular diaphragm structure was fabricated by etching the Si substrate from the back side and the unimorph actuator array composed of a PZT film and a Si layer was accomplished. Finally a Al reflective layer was coated over the backside of the membrane as a mirror surface. The displacement profiles measurements by a laser Doppler vibrometer showed that the each actuator generated large displacement of approximately 5μm at 10V. Furthermore we could successfully reproduce the Zernike modes up to 4^th order by applying the voltage calculated by control function matrix.