Analog Micro-Mirror Device
Microscale optical mirror systems are employed in such devices as flat panel displays, optical switches, scanners, interconnects and adaptive optical arrays. Recently, bulk silicon fabrication techniques have been applied to the development of such micro-mirror systems. Advantages of micro-mirror systems include compact design; low mass and operating power; and the potential for large arrays of micro-optical elements. Micro-mirror devices are often used to transmit light intensity with or without phase information.

 
The Analog Micro-Mirror Device is capable of oscillating several thousand times a second between rotations of ±5 degrees. Rotation of the mirror is induced by an applied voltage across a multilevel vertical comb drive actuator. The mirror and actuators are suspended by a single crystal silicon torsion spring. The torque applied to the torsion spring is controlled by the number of comb drive fingers, the in- and out-of-plane finger geometry, and the voltage applied. A working analog micro-mirror device was fabricated, with a 0.2 ms response time in air. The fabrication process insures an optically flat micro-mirror with less than 16nm of roughness. The device waits to be tested for applications in fiber-optic switching, scanning, and projection.