Study of stimulated and parametric emission in Rb vapor during two-photon excitation of the 5/2/D 3/2, 5/2 and 7/2/S 1/2 levels

Stimulated emission in a series of Rb infrared atomic lines, which occurs during two-photon excitation of the cited levels, is studied experimentally under conditions of pump-radiation frequency tuning. High-power parametric emission in two transitions with lines at 420.2 and 421.5 nm, respectively, was observed simultaneously with the IR emission. Probabilities are calculated for two-photon excitation of the examined levels, and it is shown that both the excitation threshold and the polarization of the IR radiation are in satisfactory agreement with theoretical estimates.