Bistable behaviors of weak probe light via coherent and incoherent fields

Abstract

In this paper, the bistable behaviors of weak probe light in a unidirectional ring cavity with a four-level atomic system are discussed. We find that in the presence of spontaneously generated coherence (SGC), the medium is completely phase dependent and the intensity threshold of optical bistability can be controlled. The effect of an incoherent pumping field on optical bistability in the presence and absence of SGC is also analyzed. Moreover, the group index behavior of weak probe light is investigated. We show that the intensity threshold of optical bistability can be controlled by light propagation switching from slow to fast by different parameters of the atomic medium.

Enhancement of Goos–Hänchen shifts due to spontaneously generated coherence in a four-level Rydberg atom

“…The properties of GH shifts in transmitted and reflected light in a fixed structure by quantum coherence and interference effects have been investigated [10, 11-13, 16, 20, 21, 23-27]. The effect of quantum coherence and interference on optical properties of many systems due to applications in optical and quantum communication has been discussed [28][29][30][31][32][33][34][35][36][37][38][39][40][41]. For the first time, Wang et al [23] investigated the role of the quantum coherence effect on GH shifts of light beams in a fixed structure doped with a two-level atomic system.…”