27 September 1999 Lick sodium laser guide star: performance during the 1998 LGS observing campaign
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Abstract
The performance of a sodium laser guide star adaptive optics system depends crucially on the characteristics of the laser guide star in the sodium layer. System performance is quite sensitive to sodium layer spot radiance, that is, return per unit steradian on the sky, hence we have been working to improve projected beam quality via improvements to the laser and changes to the launched beam format. The laser amplifier was reconfigured to a 'bounce-beam' geometry, which considerably improves wavefront quality and allows a larger round instead of square launch beam aperture. The smaller beacon makes it easier to block the unwanted Rayleigh light and improves the accuracy of Hartmann sensor wavefront measurements in the AO system. We present measurements of the beam quality and of the resulting sodium beacon and compare to similar measurements from last year.
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Donald T. Gavel, Donald T. Gavel, Herbert W. Friedman, Herbert W. Friedman, Brian J. Bauman, Brian J. Bauman, } "Lick sodium laser guide star: performance during the 1998 LGS observing campaign", Proc. SPIE 3762, Adaptive Optics Systems and Technology, (27 September 1999); doi: 10.1117/12.363588; https://doi.org/10.1117/12.363588
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