Analytical solution for the spectrum of resonance fluorescence of a cooperative system of two atoms and the existence of additional sidebands

The analytical solution for the spectrum of resonance fluorescence from a collective system of two atoms is presented. It is shown that the spectrum is a decreasing function of frequency in the neighborhood -₋=2 (is the Rabi frequency) for moderately large and exhibits resonant structure only for extremely large 100. For moderately large the resonant contributions at -₋=2 are destroyed by the nonresonant contributions; hence the additional structures at 2 can be resolved only by filtering the nonresonant contributions.