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arXiv · 1406.1006

Fast & Furious focal-plane wavefront sensing

Visa Korkiakoski·Christoph U. Keller·Niek Doelman·Matthew Kenworthy·Gilles Otten·Michel Verhaegen
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Abstract

We present two complementary algorithms suitable for using focal-plane measurements to control a wavefront corrector with an extremely high spatial resolution. The algorithms use linear approximations to iteratively minimize the aberrations seen by the focal-plane camera. The first algorithm, Fast & Furious (FF), uses a weak-aberration assumption and pupil symmetries to achieve fast wavefront reconstruction. The second algorithm, an extension to FF, can deal with an arbitrary pupil shape; it uses a Gerchberg-Saxton style error reduction to determine the pupil amplitudes. Simulations and experimental results are shown for a spatial light modulator controlling the wavefront with a resolution of 170 x 170 pixels. The algorithms increase the Strehl ratio from ~0.75 to 0.98-0.99, and the intensity of the scattered light is reduced throughout the whole recorded image of 320 x 320 pixels. The remaining wavefront rms error is estimated to be ~0.15 rad with FF and ~0.10 rad with FF-GS.

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Visa Korkiakoski, Christoph U. Keller, Niek Doelman, Matthew Kenworthy, Gilles Otten, Michel Verhaegen. 2014-06-04. Fast & Furious focal-plane wavefront sensing. https://doi.org/10.1364/ao.53.004565

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