Fabrication of Piezoelectric MEMS Deformable Mirrors for Adaptive Optics Composed of PZT thin films

摘要

In this paper we describe the piezoelectric-driven deformable mirror for adaptive optics (AO). The deformable mirror, which is used to correct the disturbed wave front, is composed of a piezoelectric PZT film deposited on a SOI substrate. The mirror membrane of 15 mm in diameter was fabricated by etching the Si wafer, while the exposed oxide layer was coated by Al layer as a mirror surface. The individual Al top electrodes were deposited on the PZT film to accomplish 19 PZT/Si unimorph actuator array. The dynamic deformation of the mirror was measured by a laser Doppler vibrometer and the large displacement more than 5μm was obtained by low operation voltage of 10V. The mirror performance was evaluated by reproducing Zernike modes and the deformed mirror surface corresponding up to 5th order of Zernike modes could be generated.