Design and development of a 329-segment tip-tilt piston mirror array for space-based adaptive optics

摘要: We report on the development of a new MEMS deformable mirror (DM) system for hyper-contrast visible nulling coronagraph architecture designed by Jet Propulsion Laboratory NASA's Terrestrial Planet Finding (TPF) mission. The DM is based largely upon existing lightweight, low power technology at Boston University (BU), tailored to rigorous optical and mechanical requirements coronagraph. It consists 329-hexagonal segments 600μm pitch, each with tip/tilt piston degrees freedom. have 1μm stroke, range 600 arc-seconds, maintain their figure within 2nm RMS under actuation. polished polycrystalline silicon surface roughness 5nm an average curvature 270mm. Designing segment that maintains its during actuation was very significant challenge faced development. Two design concepts were pursued in parallel address this challenge. first uses thick, epitaxial grown polysilicon layer add rigidity segment. second reduces bending decoupling actuator diaphragm motion from motion. This done using flexure cuts around post diaphragm. Both architectures microfabrication process are presented. Recent electromechanical characterization results will also be discussed, addition plans further improvement satisfy requirements.