Autler-Townes effect for an atom in a 100% amplitude-modulated laser field. I. A dressed-atom approach.

A dressed-state rate-equation model is used to describe the Autler-Townes effect that is produced by a resonant 100% amplitude-modulated field driving a two-level resonance. The purpose of using this model is to give an intuitive interpretation of the rather complex absorption spectra that are produced when a weak probe field couples this strongly driven transition to a third atomic state. We obtain analytic expressions for the positions, strengths, and widths of the components of the absorption spectra, which are in excellent agreement with experimentally obtained spectra presented in the accompanying paper @S. Papademetriou, following paper, Phys. Rev. A 53, 997 ~1996!#.