Optical bistability through the cavity effect in a four-level open atomic medium

The optical bistability and multistability behavior in a ring cavity for the four-level open atomic system, driven by two coupling fields has been analyzed. It is shown that the presence of exit rate from cavity is having a dominant effect on generating the optical bi(multi) stability on the system. It is found that the effects of the injection rates can be used to control the threshold intensity. It is also found that optical bistability can convert to optical multistability or vice versa via the effect of intensity and detuning of the coupling fields.