Optical bistability and multistability via the effect of spontaneously generated coherence in a three-level ladder-type atomic system

We investigate the optical bistability (OB) behavior of a nearly equispaced ladder-type three-level atomic system contained in a unidirectional ring cavity. We consider the three-level atoms under conditions that the atomic dipole moments are nonorthogonal so that the effect of spontaneously generated coherence (SGC) is important. We find that the SGC effect significantly affects the OB behavior of such system. Within certain parameter range, OB can be realized due to the SGC effect. The bistable hysteresis cycle becomes wider with the enhancement of SGC effect. Furthermore, such system is much sensitive to the relative phase between the coupling and probe fields. This property makes it possible to switch between bistability and multistability via adjusting the relative phase. (C) 2004 Elsevier B.V. All rights reserved.