High power modeless lasers for sodium laser guide stars

Abstract

An increasing number of adaptive optics systems in astronomy uses a sodium Laser Guide Star (LGS). The analysis of the distorsion of the return fluorescence requires high power lasers. We expose here two modeless laser amplifiers, based on a longitudinaly pumped 1 cm-long dye cell: the first one is a 4-pass amplifier at 589 nm pumped at 532 nm and the second one is a 4-pass amplifier at 660 nm pomped at 511 and 578 nm. These systems correspond respectively to the monochromatic and the polychromatic laser guide stars.