Shack-Hartmann wavefront sensing with elongated sodium laser beacons: centroiding versus matched filtering

Gilles, Luc; Ellerbroek, Brent L.

doi:10.1364/ao.45.006568

Cited by 73 publications

(42 citation statements)

References 7 publications

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“…But the reference image has zero center-of-mass centroid, so the correlation track algorithm will give the same centroid as the center-of-mass centroid. The same result will be true for the matched filter algorithm [16] for finding the subaperture displacements, because the reference images will still be truncated, and the true center unknown.…”

Section: Centroiding Algorithmsmentioning

confidence: 67%

Modeling low order aberrations in laser guide star adaptive optics systems

Clare¹,

Dam²,

Bouchez³

2007

Opt. Express

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When using a laser guide star (LGS) adaptive optics (AO) system, quasi-static aberrations are observed between the measured wavefronts from the LGS wavefront sensor (WFS) and the natural guide star (NGS) WFS. These LGS aberrations, which can be as much as 1200 nm RMS on the Keck II LGS AO system, arise due to the finite height and structure of the sodium layer. The LGS aberrations vary significantly between nights due to the difference in sodium structure. In this paper, we successfully model these LGS aberrations for the Keck II LGS AO system. We use this model to characterize the LGS aberrations as a function of pupil angle, elevation, sodium structure, uplink tip/tilt error, detector field of view, the number of detector pixels, and seeing. We also employ the model to estimate the LGS aberrations for the Palomar LGS AO system, the planned Keck I and the Thirty Meter Telescope (TMT) LGS AO systems. The LGS aberrations increase with increasing telescope diameter, but are reduced by central projection of the laser compared to side projection.

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Section: Centroiding Algorithmsmentioning

confidence: 67%

Modeling low order aberrations in laser guide star adaptive optics systems

Clare¹,

Dam²,

Bouchez³

2007

Opt. Express

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“…Fig. 4 shows the rms of ptv Zernike modes for a center-of-gravity (CoG) and a matched filter (MF) [4,1]. These errors are obtained by reproducing a time sequence of Na profiles and projecting the slopes deduced from both algorithms onto the Zernike polynomials.…”

Section: The Benchmentioning

confidence: 99%

The TMT/NFIRAOS LGS wavefront sensing demonstration bench

Conan

Lardière

Herriot

et al. 2010

1st AO4ELT Conference - Adaptive Optics for Extremely Large Telescopes

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Abstract.LGS wavefront sensing on ELTs is challenging. The tip-tilt indetermination, the cone effect, the star elongation, the sodium profiles fluctuations are the main problems plaguing LGS wavefront sensors. The AO Laboratory at the University of Victoria has build a LGS wavefront sensing test bed scaled for the TMT, reproducing the sodium variations and the whole NFIRAOS wavefront sensing scheme. The details of the bench design are given and the implementation of the wavefront sensing algorithm is presented. This one includes a matched filter, zoom optics control, DM command and truth wavefront sensors management.

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“…It is very commonly used in astronomical adaptive optics systems (Gilles & Ellerbroek, 2006), lens testing (Birch et al, 2010), ophthalmology (Wei & Thibos, 2010) and microscopy (Cha et al, 2010). It is used in the correction of errors due to non-flatness of spatial light modulators in holographic optical tweezer applications (López-Quesada et al, 2009).…”

Section: Introductionmentioning

confidence: 99%