MEMS arrays for deformable mirrors

A new class of silicon-based deformable mirror for use in optical applications such as adaptive optical systems and optical correlators is being built. The mirror will be a massively parallel system of electrostatically-controlled, interconnected microactuators that can be coordinated to achieve precise actuation and control at a macroscopic level. The deformable mirror system described here will be made up of a planar array of 400 electrostatically actuated actuators, which actuate a laterally continuous mirror at discrete points, resulting in surface-normal deflection of upto 4 rim. Several generations of single actuators as well as arrays of actuators with a mirror sheet over them have been designed, fabricated and tested. Deflection characteristics and pull-in behavior of the actuators have been closely studied. Tests for yield, reliability, resolution and frequency response have given optimistic results. Numerical models of the system have been developed and results from the numerical simulations agree well with experimental results.