Tunable optical multistability created by a single cavity field in an atom-cavity system.

A tunable optical multistability scheme based on a single cavity field coupled with two separate atomic transitions in an atom-cavity system is proposed and demonstrated. Under the collective strong coupling condition, optical multistability is triggered by a transmitting signal field coupled into the cavity without extra assistant light or magnetic fields. The created optical multistability curve and threshold can be tuned flexibly by system parameters in a broadband range. Moreover, a certain bistability region of the system is further split into two bistability regions due to destructive quantum interference when a weak control field is added. Compared to traditional optical multistabilities created by two or more light fields, the proposed optical multistability scheme may be designed as passive all-optical logical devices since it is compact and easy to miniaturize. The proposed scheme is useful for manufacturing integrated applications of multi-state all-optical logic devices and constructing basic elements of all-optical communication networks.