Inversionless generation of radiation in stimulated Raman and hyper-Raman scattering at allowed transitions in atoms

Abstract

The theory of stimulated Raman and hyper-Raman scattering involving resonance transitions to the ground states of atoms is presented, where the atoms are modeled by the three-level cascade quantum system. The possibility of efficient inversionless generation of radiation is shown for all three transitions participating in the stimulated Raman scattering and for the two electric-dipole allowed transitions in the hyper-Raman scattering. The existence conditions for such generation are determined depending on intensities of the three waves participating in closed-loop wave mixing, their total phase, and pump frequency detuning from the frequency of the dipole-forbidden transition. A new method of remote sensing of atomic components of the atmosphere based on inversionless generation is proposed, which may have significantly higher detection sensitivity as compared to traditional fluorescence technique.