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Proceedings Paper

New approach to Rayleigh guide beacons
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Paper Abstract

We present analysis and numerical simulations of a new method to sense atmospheric wavefront distortion in real time with Rayleigh beacons. Multiple range-gated images of a single pulse from the laser are used to determine each phase map, providing an advantage over other methods in that photon noise is substantially reduced for a given brightness of the beacon. A laser at about 350 nm projects collimated pulses of light adjacent to the telescope. Rayleigh-scattered light from each pulse is recorded through the full telescope aperture in a sequence of video frames, each a few microseconds long. Images are captured as the pulse approaches and passes through the height at which the camera is focused. Phase diversity is thus naturally introduced between the frames. An iterative algorithm is used to extract the pupil-plane phases from the recorded intensity distributions. We anticipate that such beacons are likely to be valuable in future advanced systems for adaptive optics on very large telescopes with multiple laser beacons and deformable mirrors that aim to provide a large corrected field of view by tomography of the atmospheric turbulence.

Paper Details

Date Published: 7 July 2000
PDF: 7 pages
Proc. SPIE 4007, Adaptive Optical Systems Technology, (7 July 2000); doi: 10.1117/12.390334
Show Author Affiliations
Michael Lloyd-Hart, Steward Observatory/Univ. of Arizona (United States)
Stuart M. Jefferies, Steward Observatory/Univ. of Arizona (United States)
E. Keith Hege, Steward Observatory/Univ. of Arizona (United States)
James Roger P. Angel, Steward Observatory/Univ. of Arizona (United States)

Published in SPIE Proceedings Vol. 4007:
Adaptive Optical Systems Technology
Peter L. Wizinowich, Editor(s)

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