Real time optical correction using electrostatically actuated MEMS devices

This paper describes an optical correction system made from electrostatically actuated, surface machined micro-electromechanical (MEMS) mirrors. Such MEMS mirrors have applications in optical systems where they are used to correct wavefront aberrations and other image distortions. In our experiments, electrostatic actuators having a maximum surface-normal stroke of 2.5 mu m control the individual orientations of each element in an array of 300-mu m square mirror segments in the tip-tilt mode. Real time correction of random optical aberrations is demonstrated using a single mirror segment with four independently mounted corners and closed-loop feedback control.