Coherent Perfect Photon Absorption Assisted by an Auxiliary Cavity

Abstract A coherent perfect absorption (CPA) scheme is theoretically analyzed in a three‐cavity system comprising two linear cavities and an auxiliary cavity. On account of the quantum interference stemming from the presence of the coupled auxiliary cavity, CPA can be realized by appropriately tuning system parameters. It is also demonstrated that coupling to the auxiliary cavity is the necessary and sufficient condition for the system to exhibit CPA behavior. Furthermore, by adjusting the relative phase between the input fields, asymmetric destructive interference occurs between the two cavity sides. Consequently, the output field intensity, which depends on the relative phase, can be utilized to achieve nonreciprocal opacity. The results may provide a purely optical platform for application in the development of photon control.