Compact large-stroke piston tip-tilt actuator and mirror

Devices based on SOI technology are subject to bow due to residual stress induced by the buried oxide. We have designed and fabricated a compact tunable piston tip-tilt mirror device in which the shape and the arrangement of the suspension beams result in both a reduced stress in the suspension beams and an optically flat mirror. The piston tip-tilt mirror is characterized by an accurate vertical displacement of up to 18 mm @ 80 V with good repeatability, and a tip-tilt of up to 2 mrad @ 50 V.