The susceptibility spectrum and parametric generation in atomic vapors in a resonant light field

The absorption spectra of two-level atoms in mono- and bichromatic fields and three-level atoms in a monochromatic pumping field are studied theoretically and experimentally. The enhancement of Stokes and anti-Stokes waves propagating in a nonlinear medium is investigated. Parametric generation is obtained with sodium and barium atoms in the cavity of one- and two-frequency dye lasers. The generation in the vapor of barium atoms in a bichromatic pumping field is obtained with symmetric detuning of the pumping field frequencies with respect to the resonance transition frequency.