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

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