Semiclassical dressed-atom approach

A semiclassical approach to the dressed-atom theory is presented in which dressed energies and slates are determined from the solutions of the semiclassical coupled equations for the atomic probability amplitudes. The semiclassical approach has an advantage over the standard quantum-mechanical approach, especially when an atom interacting with a nonmonochromatic field is considered, because the standard approach requires diagonalization of an infinite-dimensional Hamiltonian matrix for an evaluation of dressed energies and states. Explicit expressions for dressed states of a two-level atom interacting with a resonant monochromatic, bichromatic, and trichromatic field are given.