Polarization dependence of optical bistability in the presence of external magnetic field

In this paper, a four-level inverted Y type atomic system for controlling the optical bistability and multistability is proposed. An elliptically polarized probe field and a coherent coupling field in the presence of external magnetic field are interacted by this medium. It is shown that the external magnetic field and relative phase between two electric field components of the probe field can influence the threshold of optical bistability. Moreover, it is found that optical bistability can be converted to the optical multistability by external magnetic field and relative phase. (C) 2013 Elsevier B.V. All rights reserved.