Abstract

Recently, Lavoine et al.¹ have analyzed a two-photon degenerate four-wave-mixing process in homogeneously broadened two-level systems with transition as well as permanent dipole moments. The model was intended to describe polar molecules embedded in a solvent. The environment was taken into account through phenomenological relaxation and dephasing constants: this is the Markovian limit of statistical physics applied to this case. The difference in permanent dipole moments between the ground and excited states leads to a resonance in the third-order response around half the transition energy.

© 1994 IEEE