Design of Deformable Focusing Micromirrors

Abstract A deformable mirror is an adaptive optical device that can deform its surface shape to self-adjust its focal length. This paper designed a center-anchored circular deformable micromirror, which is a two-layer structure; a metal layer atop a structure layer, fabricated using surface micromachining process and actuated by electrostatic force. A series of simulations are performed to investigate the process- and voltage-induced deformations and thus to determine the focal length under various parameters for the designed micro-mirror. Because of warpage occurring after release, the two-layer center-anchored circular plate was cut into several sectors when fabricated, in which the diameters of the circular plate and the centric anchor are 500 (before deformation) and 100 μms, respectively. The profiles of deformable mirror are measured and the curvature radius measured is estimated from 200 to 400 μm.