Closed-loop aberration correction by use of a modal Zernike wave-front sensor

Opt. Lett., Vol. 25, No. 15, Aug. 2000, 1083-1085. M.A.A. Neil, M.J. Booth & T. Wilson

We describe the practical implementation of a closed-loop adaptive-optics system incorporating a novel modalwave-front sensor. The sensor consists of a static binary-phase computer-generated holographic element,which generates a pattern of spots in a detector plane. Intensity differences between symmetric pairs ofthese spots give a direct measure of the Zernike mode amplitudes that are present in the input wave front.We use a ferroelectric liquid-crystal spatial light modulator in conjunction with a 4 f system and a spatialfilter as a wave-front correction element. We present results showing a rapid increase in Strehl ratio andfocal spot quality as the system corrects for deliberately introduced aberrations. © 2000 Optical Society ofAmerica

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