Threshold and dispersion effects in the anti-Stokes Raman laser

Abstract

Threshold characteristics for an anti-Stokes Raman laser based on inverted, metastable ${\text{Tl}}^{*}(6p{{}^{2}P}_{3/2}^{\circ })$ atoms are studied. Raman upconversion of a tunable dye laser at 535 to 378 nm is observed with an overall tuning range of 1125 cm⁻¹ for a single-pass laser device. The anti-Stokes pump-laser threshold varies inversely as the square of the detuning from the intermediate Raman level, except in a region ~50 cm⁻¹ to either side of the resonance, where the threshold is constant. These observations are explained in terms of group-velocity dispersion effects and are in good agreement with a simple theoretical model.