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Proceedings Paper

Polychromatic laser guide star using a single laser at 330 nm
Author(s): Jean-Paul Pique; Ioana C. Moldovan; Vincent Fesquet; Hugues Guillet de Chatellus; Fabien Marc
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Paper Abstract

The differential atmospheric tip-tilt can be measured using a Polychromatic Laser Guide Star. A two photon excitation has been proposed. It consists in exciting the 4D5/2 level of mesospheric sodium atoms with two identical lasers operating at 589 nm and 569 nm. With two modeless lasers of 2×15W at the mesosphere level, this scheme will produce a returned flux at 330 nm of about 4×104 photons/s/m2. Thanks to our modeless laser, we propose a new method which consists in exciting directly the 4P3/2 sodium level with one photon excitation, using a single laser operating at 330 nm. This solution was previously rejected probably because of strong saturation problems using single longitudinal mode lasers. We show that 1 W modeless laser at 330 nm can produce the same returned flux at 330 nm. This solution will save at least 400 k€ of equipment. Moreover, our new method is very promising in terms of simplicity but also in terms of flux because the returned flux above will probably be not sufficient for getting a good Strehl ratio. We propose very efficient solid state laser systems for the production of tens of watts at 330 nm.

Paper Details

Date Published: 28 June 2006
PDF: 10 pages
Proc. SPIE 6272, Advances in Adaptive Optics II, 62723D (28 June 2006); doi: 10.1117/12.692350
Show Author Affiliations
Jean-Paul Pique, Lab. de Spectrométrie Physique, Univ. Joseph Fourier, CNRS (France)
Ioana C. Moldovan, Lab. de Spectrométrie Physique, Univ. Joseph Fourier, CNRS (France)
Vincent Fesquet, Lab. de Spectrométrie Physique, Univ. Joseph Fourier, CNRS (France)
Hugues Guillet de Chatellus, Lab. de Spectrométrie Physique, Univ. Joseph Fourier, CNRS (France)
Fabien Marc, Lab. de Spectrométrie Physique, Univ. Joseph Fourier, CNRS (France)


Published in SPIE Proceedings Vol. 6272:
Advances in Adaptive Optics II
Brent L. Ellerbroek; Domenico Bonaccini Calia, Editor(s)

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