Four-photon parametric luminescence under conditions of two-frequency excitation of metal vapor by ultrashort light pulses

A theoretical analysis is made of the frequency, angular, and energy characteristics of four-photon parametric luminescence in sodium vapor under conditions of two-frequency excitation of the 3S–3D transition by ultrashort light pulses undergoing coherent interaction. The frequency and angular ranges of the efficient scattering were determined for various excitation geometries of the medium. A comparison was made between the theoretical results and the experimental data obtained previously.