USE EF MICROELECTROMECHANICAL DEFORMABLE MIRRORS TO CONTROL ABERRATIONS IN OPTICAL-SYSTEMS - THEORETICAL AND EXPERIMENTAL RESULTS

Micro-electro-mechanical deformable mirrors (MEM-DMs) are solid-state electronic devices with small, movable reflective surface elements tha t can be used to manipulate the phase of optical wavefronts. MEM-DMs d iffer from more conventional continuous-facesheet deformable mirrors i n that the movable surface of a MEM-DM consists of a set of segmented moving surfaces. The segmented, reflective surfaces of a MEM-DM give r ise to larger diffraction effects than those provided by continuous-fa cesheet deformable mirrors. However, MEM-DMs are still attractive due to their low cost and the low drive voltages. We explore the theoretic al limits of performance of MEM-DMs for controlling fixed aberrations in optical systems, and we present laboratory results demonstrating re duction of a fixed aberration using a MEM-DM device. Results presented here show that while a MEM-DM does provide some degree of aberration control, diffraction effects arising from the static support structure s of the MEM-DM surface are significant. An alternative design that us es a lenslet array in conjunction with the MEM-DM is shown through the oretical studies to provide superior aberration correction with lower residual effects due to diffraction. (C) 1997 society of Photo-Optical Instrumentation Engineers.