Resonant gain suppression and quantum destructive interference in a three-level open V system

Abstract

We investigate the steady optical properties of a three-level open V system (i.e. a four-level closed atomic system) through both analytical and numerical calculations. Our results show that the resonant probe gain can be greatly suppressed to generate a narrow and deep transparency window associated with very steep abnormal dispersion. The underlying physics is identified as the perfect quantum destructive interference between a pair of dressed state transition pathways, which is usually believed to be absent in three-level closed V systems. In addition, we show that the transparency window and its associated abnormal dispersion can be used to realize a striking propagation dynamics where a light pulse may have a negative group velocity of small absolute values and experience little gain or absorption.