Individually Tunable Array of Micro Fresnel Mirrors

Abstract:
We present the control and characterization of a miniaturized array of piezoelectrically actuated high speed Fresnel mirrors with individual mirror control. The array consists of four Fresnel mirrors each having an area of 2 x 2 mm2 arranged in a 2 x 2 configuration. To compensate for the variation in the mirror angle of individual mirrors in the array, we developed a driver circuit to control each mirror individually. The circuit, capable of generating four separate high voltage signals, was able to operate at frequencies up to 20 kHz. When operated quasi statically, the mechanical cross-talk from the neighboring mirrors in the array was smaller than λ=4. We also investigate the effect of mechanical coupling on the resonance frequency of the mirrors and the effect of creep and temperature on the mirror angle.