A micromachined deformable mirror for optical wavefront compensation Thomas Bifano1, Julie Perreault2, and Paul Bierden3, ABSTRACT A silicon micromachined deformable mirror QiDM) has been developed by Boston University and Bos- ton Micromachines Corporation (BMC). The pDM employs a flexible silicon mirror supported by me- chanical attachments to an array of electrostatic parallel plate actuators. The integrated system of mirror and actuators was fabricated by surface micromachining using polycrystalline silicon thin films. The mirror itself measures 3 mm x 3 mm x 3 jim, supported by a square array of 140 electrostatic parallel- electrode actuators through 140 attachment posts. Recently, this pDM was characterized for its electro- mechanical and optical behavior and then integrated into two laboratory-scale adaptive optics systems as a wavefront correction device. Figures of merit for the system include stroke of 2 jim, resolution of 10 nm, and frequency bandwidth of 6.7 kHz. The device is compact, exhibits no hysteresis, and has good optical quality. Keywords — Adaptive optics, MEMS, MOEMS, micromachining, deformable mirror, electrostatic ac- tuation, phase conjugation, aberration compensation, optical phase correction, wavefront correction 'Corresponding author, Professor of Manufacturing Engineering, Boston University, 15 St Mary s St., Boston MA 02215, tgb@bu.edu, (617) 353-5619 2 Graduate student, Electrical and Computer Engineering, Boston University, Boston, MA, (617) 353-9370 President, Boston Micromachines Corporation, P0 Box 15700, Boston, MA, 02215, (617) 905-6703 High-Resolution Wavefront Control: Methods, Devices, and Applications II, John D. Gonglewski, Mikhail A. Vorontsov, Mark T. Gruneisen, Editors, Proceedings of SPIE Vol. 4124 (2000) © 2000 SPIE. · 0277-786X/00/$15.00 7