Radiative renormalization analysis of two-level systems with permanent dipole moments.

Abstract

The radiative renormalization technique is used to analyze two-level systems with permanent dipole moments under the influence of a single-frequency applied field. The advantage of radiative renormalization over the usual perturbative or harmonic balance techniques lies in the computational ease with which the density matrix operators can be determined to any order in applied field. We characterize the absorption and dispersion of a typical two-level system within this framework and find that although the absorption saturates as expected with increasing incident field strength, additional oscillatory behavior is evident at extremely high field strengths. The structure and period of these oscillations is dependent upon the magnitude of the permanent dipole moment. Our general formalism can easily be extended to the study of other nonlinear optical phenomena. \textcopyright{} 1996 The American Physical Society.