Conditions for the observation of the Autler-Townes effect in a two step resonance experiment

Abstract
The object of this paper is to derive theoretically the conditions for the observation of the Autler-Townes splitting in a two step resonance experiment involving the simultaneous effects of two visible monochromatic radiations in a three-level system. First, the three-level system is considered at rest and optical pumping to other levels is ignored; in this case, the problem is solved analytically. Following this case, optical pumping effects are taken into account. Finally, one considers a collection of identical three-level systems in a cell, the two light beams traveling either in the same direction or in two opposite directions. In this latter case, the problem is practically identical to the one for a three-level system at rest