Controllable optical bistability with perfect photon absorption

We propose a scheme for controlling nonlinear coherent perfect absorption (CPA) in a three-level A-type atom-cavity system. Generally, the normally nonlinear CPA and the bistable CPA can be attained at different frequencies of an input probe field. With a coherent control field coupling one of the ground states and the excited state of the atoms, two types of CPA can be attained at the same frequency. Besides, for the bistable CPA, the highest output-input ratio of the high stable state and the low stable state is approximately 1, and the threshold and the hysteresis cycle of the bistability are controllable by the control field. The results of our study may potentially be applied in optical bistable switching and optical logic devices. (C) 2022 Elsevier B.V. All rights reserved.