Coherent Perfect Absorption Mediated Enhancement and Optical Bistability in Phase Conjugation

Coherent perfect absorption has been one of the important research directions in optics in recent years because of its ability to absorb all the incident light. It has been extended to nonlinear regime to show multistability and gap solitons in nonlinear periodic structures. We study yet another nonlinear effect, namely, phase conjugation in a Kerr nonlinear composite slab when the counter propagating pump waves are completely absorbed by means of coherent perfect absorption. The theory is developed under the undepleted pump approximation, when the pump waves can be decoupled from the signal and the phase conjugated waves. Dynamical phase matching is also incorporated. The coupling constant and the phase conjugated reflectivity are shown to undergo a substantial increase. They also exhibit multivalued response. Both downward and upward switching are shown to be possible. The effect can be used for efficient switching of the phase conjugated reflectivity in photonic circuits and can find several application in photonic logic gates.

phase conjugation, coherent perfect absorption, switching, Kerr medium, multistability