Two-photon selective reflection

Abstract

The conditions of observation of direct two-photon-induced dispersion in three-level reflection spectroscopy at a vapor-dielectric interface are discussed. One shows how pump frequency modulation allows one to discriminate the two-photon singular contribution associated with atoms moving quasiparallel to the dielectric interface, and therefore single out off-resonant Doppler-free two-photon dispersion in selective reflection. A nonperturbative theoretical approach to two-photon reflection is shown to predict a dynamic Stark shift of the two-photon resonance, which has been experimentally observed on the 6S-6P-8S transition of cesium. \textcopyright{} 1996 The American Physical Society.