Field tests of wavefront sensing with multiple Rayleigh laser guide stars and dynamic refocus

Thomas E. Stalcup, James A. Georges, Miguel Snyder, Christoph Baranec, Nicole Putnam, Mark Milton, Roger Angel, Michael Lloyd-Hart

Research output: Contribution to journalConference articlepeer-review

18 Scopus citations


A demonstration of tomographic wavefront sensing has been designed, fabricated, and tested. The last of the initial testing of the dynamic refocus system at the 61" telescope on Mt. Bigelow, Arizona is presented, along with the first results from the system after its transfer to the 6.5 m MMT on Mt. Hopkins, Arizona. This system consists of a laser beam projector, and a wavefront sensor at the telescope's Cassegrain focus. The projector transmits 5 pulsed 532 nm beams in a regular pentagon of 2 arcminutes diameter from behind the telescope's secondary mirror that in good seeing can yield sub-arcsecond beacons over a 20-30 km altitude range. The wavefront sensor incorporates a dynamic refocus unit to track each returning laser pulse, and a multiple laser beacon Shack-Hartmann wavefront sensor using a novel substitute for the traditional lenslet array. A natural guide star wavefront sensor was also fielded to collect ground-truth data to compare with wavefronts reconstructed from the laser wavefront sensor measurements. All of the subsystems were shown to work, but bad weather ended the testing before the final data could be collected.

Original languageEnglish (US)
Article number29
Pages (from-to)1021-1032
Number of pages12
JournalProceedings of SPIE - The International Society for Optical Engineering
Issue numberPART 2
StatePublished - 2004
EventAdvancements in Adaptive Optics - Glasgow, United Kingdom
Duration: Jun 21 2004Jun 25 2004


  • Atmospheric Tomography
  • Beacon
  • Dynamic Refocus
  • Focal Anisoplanatism
  • Laser Guide Stars
  • Multi-Conjugate Adaptive Optics
  • Rayleigh

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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