Controllable phase-dependent optical switch in an atom-cavity system

Coherent perfect absorption (CPA) and coherent perfect transmission (CPT) are two extreme states that occur by the manipulation on optical fields. Generally, CPA and CPT occur under different input-field phases. Therefore, we propose a scheme to realize an all-optical switch by phase-dependent CPA-CPT conversion. In our proposal, the CPT state and the CPA state are treated as an on state and an off state, respectively. Consequently, the efficiency of this all-optical switch can reach the maximum value of 1. By an incoherent pump field, the CPA state can be achieved under a weaker input probe field or can be transferred as a CPT state. The results show that the optical switch can operate with weaker fields and can be optimized by application of an incoherent field.