Large dynamic range wavefront control of micromachined deformable membrane mirrors

Micromachined deformable membrane mirrors (MDMMs)(1) are currently being integrated into or proposed for numerous space-based imaging applications, including systems that utilize phase diversity,(2) foveated imaging,(3-4) and active or adaptive optical zoom.(5-7) In stark contrast to applications that require only a few waves of optical stroke, such as atmospheric turbulence correction, these applications often require that the mirrors operate over much larger dynamic ranges. In order to obtain near diffraction-limited performance, these mirrors must be capable of producing wavefronts with accurate figures to within a quarter-wave (P-V). Recent experimental results will be discussed, in which MDMMs produced focal lengths as low as 2.5m with near diffraction-limited performance.