Resonance Fluorescence of Atoms at High Photon Densities

Abstract

Some general remarks and suggestions are presented concerning one- and two photon resonance fluorescence spectra, which arise from two- and three-level atoms interacting with strong light fields. Cooperative effects in the two-atom resonance fluorescence spectra are considered, where two-level atoms are resonantly pumped by a laser, while the atoms interact through their dipole-dipole interaction and radiate to each other as well. The possibility to measure experimentally the dipole-dipole energy through the observation of the collective modes of the system for one- and two-photon processes is discussed. The physical process describing a three-level atom interacting with two lasers is considered, where each laser resonantly couples the ground state with one of the excited states of the atom, respectively. Numerical computation of the spectral function, which describes the excitation spectrum of the system in question, indicates that at each transition frequency there may exist either one-pair or two-pairs or three-pairs of sidebands, in addition to the central peak, depending upon the relative strength of the Rabi frequencies involved. Quantum beats occuring in one- and two-photon resonance fluorescence of three-level atoms at high photon densities are briefly discussed.