Optical Multistability from a Squeezed Vacuum in the Presence of Quantum Interference

The effect of a squeezed vacuum on the optical bistable and multistable behaviour of a system of N three-level atoms is investigated, where the quantum interference between the atomic transition paths is considered. It is shown that the squeezed vacuum can profoundly affect the output field of this system. A strong squeezed vacuum can lead to multistable behaviour, even in the case where the cooperation parameter C is so small that the input–output relationship curve is monotone in the absence of the squeezed vacuum. The optical multistability is most significant when the quantum interference is perfect. The bistability and multistability can be controlled by the squeezing photon number and the strength of the two-photon correlation.