Surface micromachined deformable mirrors

At Boston University, we have begun a project to surface-machined microactuators coordinated to achieve precision actuation and control of deformable mirrors. Beyond its value as a demonstration project for MEMS arrays, the deformable mirror project represents a significant advance in the field of adaptive optics: an inexpensive, easily reproduced, non-piezoelectric, low-power device for modulation of optical wavefronts. The mirror will be supported on a massively parallel system of electrostatically-controlled, interconnected microactuators that can be coordinated to achieve precise actuation and control at a macroscopic level. Several generations of individual actuators as well as parallel arrays of actuators with segmented/continuous mirrors have been designed, fabricated and tested. Deflection characteristics and pull-in behavior of the actuators have been closely studied. Devices have been characterized with regard to yield, repeatability and frequency response. An electromechanical model of the system has been simulated numerically using the shooting method, and good correlation with experimental results has been obtained. A twenty channel parallel control scheme has been developed and implemented on a segmented mirror array.