New approach to Rayleigh guide beacons

M. Lloyd-Hart, S. M. Jefferies, E. K. Hege, J. R.P. Angel

Research output: Contribution to journalConference articlepeer-review

4 Scopus citations


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 μs 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.

Original languageEnglish (US)
Pages (from-to)I/-
JournalProceedings of SPIE - The International Society for Optical Engineering
StatePublished - 2000
EventAdaptive Optical Systems Technology - Munich, Ger
Duration: Mar 29 2000Mar 31 2000

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Computer Science Applications
  • Applied Mathematics
  • Electrical and Electronic Engineering


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