Tests on micro-mirror arrays for adaptive optics

Micro Mirror Arrays (MMAs) offer a high speed and high resolution technology for wavefront control applications. In this paper a new MMA type is investigated. As opposed to most other MMA technologies which involve flip mirror with only two possible orientations, this chip contains mirrors that can perform a piston-like and quasi-continuous motion, thus modulating the phase of the reflected light. The MMA`s wavefront correction capabilities are being tested in a breadboard that simulates continuous distortions and step errors, such as those that could be expected from lightweight primary mirrors of space telescopes or segmented mirrors, respectively. The wavefront is corrected by the MMA, then coupled into a monomode fiber. Three different correction methods are tested, a stochastic approach, a closed-loop Shack-Hartman approach and an interferometric approach. Comparison of coupling efficiency is made between the approaches and against theoretical calculations.