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Proceedings Paper

Anti-aliasing optical method for Shack Hartmann WFSs
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Paper Abstract

Measurement errors due to aliasing in a Shack-Hartmann WFS are typically 40% larger in variance than the fitting error of an AO system. On bright stars, aliasing is the dominant error within the control radius of the deformable mirror. Wavefront spatial frequencies beyond the WFS’ Nyquist frequency corrupt measurements below this frequency. A common misconception is to think that aliasing primarily affects the higher spatial frequency measurements. But in fact aliasing propagates to the lowest order modes, and corrupts even tip/tilt. There are many examples including the observation that the temporal power spectrum of measured tip/tilt from a WFS does not correspond to Kolmogorov theory. We propose a simple optical modification to a SH WFS (borrowed from the digital video camera industry), and present simulation results showing that the aliasing errors are reduced.

Paper Details

Date Published: 26 July 2016
PDF: 5 pages
Proc. SPIE 9909, Adaptive Optics Systems V, 99091Z (26 July 2016); doi: 10.1117/12.2231801
Show Author Affiliations
Glen Herriot, Herzberg Astronomy & Astrophysics, National Research Council Canada (Canada)
Jean-Pierre Véran, Herzberg Astronomy & Astrophysics, National Research Council Canada (Canada)

Published in SPIE Proceedings Vol. 9909:
Adaptive Optics Systems V
Enrico Marchetti; Laird M. Close; Jean-Pierre Véran, Editor(s)

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