Characterization of a micromachined membrane deformable mirror

The purpose of this work was to evaluate a 37 channel micromachined membrane deformable mirror which is a component used in adaptive optics. Several transfer functions with different mirror bias shapes were determined and analyzed. An interferometer was used to measure and to evaluate the transfer functions. The capacity of the mirror to produce wavefronts containing single Zernike coefficients was tested with an open loop scheme. A closed loop scheme was used for one of the transfer functions to construct three different Zernike polynomials. The results show that the mirror has a capacity to produce wavefronts using Zernike polynomials with coefficient values that have the magnitude of a few radians measured relative the bias. The number of the mirror eigenmodes used in the wavefront reconstruction was found to be of major importance. The closed loop reconstruction scheme enhanced the results in comparison to the open loop scheme.