Adaptive optic correction using silicon-based deformable mirros

摘要

A micromachined deformable mirror ($mu@-DMs) for optical wavefront correction is described. Design and manufacturing approaches for $mu@-DMs are detailed. The $mu@-DM employs a flexible silicon membrane supported by mechanical attachments to an array of electrostatic parallel plate actuators. Devices are fabricated through surface micromachining using polycrystalline silicon thin films. $mu@-DM membranes measuring 2 mm $MUL 2 mm $MUL 2 $mu@m, supported by 100 actuators are described. Figures of merit include stroke of 2 $mu@m, resolution of 10 nm, and frequency bandwidth DC - 7 kHz. The devices are compact, inexpensive to fabricate, exhibit no hysteresis, and use only a small fraction of the power required for conventional DMs. Performance of an adaptive optics system using a $mu@-DM was characterized in a closed-loop control experiment. Significant reduction in quasi-static wavefront phase error was achieved. Advantages and limitations of $mu@-DMs are described, in relation to conventional adaptive optics systems and to emerging applications of adaptive optics, such as high resolution correction, small aperture systems, and optical communication.