Optical bistability and multistability via dual electromagnetically induced transparency windows

We investigate the optical bistability and multistability behaviors in a four-level image system using a microwave field driving a hyperfine transition between two lower states inside a unidirectional ring cavity. By controlling the microwave field and the frequency detunings of the three fields, we find that the appearance and disappearance of OB (or OM) can easily be controlled by adjusting the positions of the dual-EIT windows. Our scheme may be used for building more efficient all-optical switches and logic-gate devices for optical computing and quantum information processing.