Steady-state fluorescence intensity of two identical atoms with dipole-dipole interaction

The dependence of steady-state fluorescence of a diatomic system on the frequency of a laser field is investigated. The steady-state fluorescence intensity can be presented in special geometry as the sum of two parts. The first part is described using an independent two-level system. The second is related to the two-photon excitation process and is described using a three-level system. The respective analytical expressions are obtained for the line profiles, their width, and intensity at the maxima.