Electrostatically actuated membrane mirrors for adaptive optics

We are developing membrane mirrors for use in adaptive optics, particularly in astronomy and vision science. We have micro-fabricated membrane mirrors from single crystal silicon using wet chemical etching and reactive ion etching. Membrane size, tension and operating voltage-were selected to allow greater deformation of the mirror surface at lower operating voltages than previous membrane mirror designs. Mirror devices consist of independently fabricated membrane and electrode array chips that are flip chip bonded together. We-have fabricated electrode arrays with 256 and 1024 electrodes, and active diameters ranging from 6-10 nun (comparable to the size of the human pupil). Membrane devices are mounted to ceramic packages, wire bonded, and driven by off chip, D/A electronics. These devices are milestones in the development of an electret membrane mirror.