Adaptive Optics for Extremely Large Telescopes 4 – Conference Proceedings

The discrete sampling of a wave-front using a Shack-Hartmann sensor limits the maximum spatial frequencywe can measure and impacts sensitivity to frequencies at the high end of the correction band due to aliasing.Here we present Wiener lters for wave-front reconstruction in the spatial-frequency domain, ideally suited forsystems with a high number of degrees of freedom. We develop a theoretical anti-aliasing (AA) Wiener lterthat optimally takes into account high-order wave-front terms folded in-band during the sensing (i.e., discretesampling) process. We present Monte-Carlo simulation results for residual wave- fronts and propagated noise andcompare to standard reconstruction techniques (in the spatial domain). To cope with nite telescope aperturewe've developed and optimised a Gerchberg-Saxton like iterative-algorithm that provides superior performance.