First significant image improvement from a sodium-layer laser guide star adaptive optics system at Lick Observatory

Technical Report · Mon Jul 14 00:00:00 EDT 1997

DOI:https://doi.org/10.2172/576003· OSTI ID:576003

Olivier, S S; Max, C E; Friedman, H W; An, J; Avicola, K; Beeman, B V; Bissinger, H D; Brase, J M; Erbert, G V; Gavel, D T; Kanz, K; Macintosh, B; Neeb, K P; Waltjen, K E

Atmospheric turbulence severely limits the resolution of ground-based telescopes. Adaptive optics can correct for the aberrations caused by the atmosphere, but requires a bright wavefront reference source in close angular proximity to the object being imaged. Since natural reference stars of the necessary brightness are relatively rare, methods of generating artificial reference beacons have been under active investigation for more than a decade. In this paper, we report the first significant image improvement achieved using a sodium-layer laser guide star as a wavefront reference for a high- order adaptive optics system. An artificial beacon was created by resonant scattering from atomic sodium in the mesosphere, at an altitude of 95 km. Using this laser guide star, an adaptive optics system on the 3 m Shane Telescope at Lick Observatory produced a factor of 2.4 increase in peak intensity and a factor of 2 decrease in full width at half maximum of a stellar image, compared with image motion compensation alone. The Strehl ratio when using the laser guide star as the reference was 65% of that obtained with a natural guide star, and the image full widths at half maximum were identical, 0.3 arc sec, using either the laser or the natural guide star. This sodium-layer laser guide star technique holds great promise for the world`s largest telescopes. 24 refs., 4 figs., 1 tab.

• Research Organization: Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 576003
• Report Number(s): UCRL-JC-128088; CONF-970706-; ON: DE98051086
• Resource Relation: Conference: Annual meeting of the Society of Photo-Optical Instrumentation Engineers, San Diego, CA (United States), 27 Jul - 1 Aug 1997; Other Information: PBD: 14 Jul 1997
• Country of Publication: United States
• Language: English

Related Subjects

44 INSTRUMENTATION
INCLUDING NUCLEAR AND PARTICLE DETECTORS
LIGHT SOURCES
FOCUSING
OPTICAL SYSTEMS
TELESCOPES
CORRECTIONS
TURBULENCE
PERFORMANCE
CONTROL SYSTEMS
SPATIAL RESOLUTION
EXPERIMENTAL DATA