Observations of stimulated anti-Stokes radiation in barium vapour

Abstract
Stimulated anti-Stokes emission at 457.6 nm accompanying the transition from the 3D2 metastable to the 1S0 ground state in barium has been observed when the output of a dye laser is tuned close to the intercombination line at 791.1 nm. The emission is interpreted as parametric four-wave coupling. Scattering at other frequencies is also observed and the possibility of using this process to produce tunable ultraviolet light is briefly discussed.