The influence of laser linewidth on the brightness of sodium laser guide star in midlatitude atmosphere
L.A. Bolbasova, S.A. Ermakov, V.P. Lukin
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: laser guide star, adaptive optics, atmospheric turbulence, telescope, astroclimate
Abstract
The technique of laser reference stars is an integral part of modern adaptive optical systems of ground-based telescopes. The requirements for the energy, spectral, and spatiotemporal characteristics of a laser beam for creating sodium laser guide star, as well as for the adaptive optical system as a whole, are largely related to the atmospheric parameters of telescope site. One aspect of optimizing the brightness of a sodium laser guide star is the choice of linewidth of the laser. In this work, based on numerical simulation of the interaction of laser radiation with mesospheric sodium atoms under the conditions of midlatitude atmosphere in the Russian Federation, the effect of laser bandwidth on the magnitude of the return photon flux from a sodium laser guide star is estimated to determine the requirements for the parameters of the laser. Results are presented for laser radiation with circular polarizations and linewidths from 10 MHz to 3.5 GHz.
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