title: Concept for polychromatic laser guide stars: one-photon excitation of the 4P3/2 level of a sodium atom.
abstract: One challenge for polychromatic laser guide stars is to create a sufficiently intense source in the UV. The flux required for the measurement of differential tip-tilt is the main issue that we address. We describe a model that has been validated using on-sky data. We present a method that excites the 4P3/2 sodium level using a one-photon excitation at 330 nm. It is more efficient than the two-photon excitation previously suggested since its power slope flux is 3 x 10(4) photons/s/m2/W instead of 1.3 x 10(3) photons/s/m2/W. This method is very promising both in terms of flux and system simplicity.
authors.affiliation: Laboratoire de Spectrométrie Physique, Université Joseph Fourier, UMR 5588 CNRS- Grenoble I, B.P. 87, 38402 Saint Martin d'Hères, France. pique@spectro.ujf.grenoble.fr
authors.forename: Jean-Paul
authors.initials: JP
authors.lastname: Pique
authors.forename: Ioana Cristina
authors.initials: IC
authors.lastname: Moldovan
authors.forename: Vincent
authors.initials: V
authors.lastname: Fesquet