Abstract

The subaperture images in Shack–Hartmann wavefront sensors are elongated when using sodium laser guide stars, due to the parallax effect and the nonzero thickness of the sodium layer. This elon gation increases the measurement error in each subaperture and introduces a correlation between the measurements in the orthogonal x and y pixel axes. We show, via end-to-end numerical simulations, that including these errors in a matrix-vector-multiply maximum a posteriori reconstructor sig nificantly improves the expected performance of a laser tomography adaptive optics system for the $42\mathrm{m}$ diameter European Extremely Large Telescope. In particular, including this noise-weighted re construction shows the detected photon requirement is similar for both central and side launch of the sodium lasers.

© 2010 Optical Society of America

Laser guide star wavefront sensing for ground-layer adaptive optics on extremely large telescopes

Richard M. Clare, Miska Le Louarn, and Clementine Béchet
Appl. Opt. 50(4) 473-483 (2011)

Optimal reconstruction for closed-loop ground-layer adaptive optics with elongated spots

Clémentine Béchet, Michel Tallon, Isabelle Tallon-Bosc, Éric Thiébaut, Miska Le Louarn, and Richard M. Clare
J. Opt. Soc. Am. A 27(11) A1-A8 (2010)

Tomographic wavefront error using multi-LGS constellation sensed with Shack–Hartmann wavefront sensors

Clélia Robert, Jean-Marc Conan, Damien Gratadour, Laura Schreiber, and Thierry Fusco
J. Opt. Soc. Am. A 27(11) A201-A215 (2010)

Efficient reconstruction method for ground layer adaptive optics with mixed natural and laser guide stars

Roland Wagner, Tapio Helin, Andreas Obereder, and Ronny Ramlau
Appl. Opt. 55(6) 1421-1429 (2016)

Mitigation of truncation effects in elongated Shack–Hartmann laser guide star wavefront sensor images

Richard M. Clare, Stephen J. Weddell, and Miska Le Louarn
Appl. Opt. 59(22) 6431-6442 (2020)