Hard-collision broadening of the probe-field spectrum in a Λ-system

Abstract

The probe-field spectrum of a three-level Λ-gaswith hard collisions between particles is studied. The shape and positions ofcomponents of the Autler–Townes doublet are obtained at different collisionfrequencies. When the Doppler broadening is much greater than the collisionfrequency the width of the peaks is found to be proportional to the collisionfrequency. In contrast when collisions are elastic the peaks are shown to narrowdue to the Dicke effect.