Probing the spatial dispersion in a dense atomic vapor near a dielectric interface

Abstract

We have experimentally investigated the selective reflection of the $P\ensuremath{-}D$ transition in a high-density rubidium vapor and shown it to be sensitive to the exact spatial distribution of $P$-state atoms near the dielectric-vapor interface. This distribution results from the radiative and nonradiative transport of excitation and from wall-quenching collisions of excited-state atoms and is highly inhomogeneous. Selective reflection thus acts as a probe of the spatial dispersion in the vapor. The resulting spectra have been analyzed to show that the broadening due to $S\ensuremath{-}D$ collisions contributes considerably to the self-broadened linewidth of the $P\ensuremath{-}D$ transition.