Implications of the trapping-desorption and direct inelastic-scattering channels on Dicke-narrowed line shapes.

Abstract

The Dicke-narrowed line shape of an atom in a wall-coated, bufferless atomic storage cell is composed of two parts, a sharp central spike and a broad underlying pedestal. To understand the pedestal shape we find that it is necessary to account for various atom-surface scattering channels. Conversely, analysis of the pedestal shape yields information concerning these scattering channels. In particular, nearly-Doppler-broadened pedestals, observed for alkali-metal hyperfine transitions in cells with paraffin coatings, indicate that both a trapping-desorption channel and a direct inelastic or quasielastic channel are accessible in the atom-surface scattering process. Alternatively, the appearance of much narrower pedestals, observed in cells with dichlordimethysilane coatings, indicates that the trapping-desorption channel dominates the atom-surface scattering process.