Centroid gain compensation in Shack-Hartmann adaptive optics systems with natural or laser guide star
In an adaptive optics system with an undersampled Shack-Hartmann wave-front sensor (WFS), variations in seeing, laser guide star quality, and sodium layer thickness and range distance all combine to vary WFS centroid gain across the pupil during an exposure. While using the minimum of 4 pixels per WFS subaperture improves frame rate and read noise, the WFS centroid gain uncertainty may introduce static aberrations and degrade servo loop phase margin. We present a novel method to estimate and compensate WFS gains of each subaperture individually in real time for both natural and laser guide stars.
Veran
JP
Herzberg Institute of Astrophysics, National Research Council of Canada, Victoria, British Columbia. jean-pierre.veran@nrc.ca
Herriot
G