Switchable resonance in vertical dual-cavity structure containing graphene.

We propose and theoretically demonstrate a novel type of an all-optical switch using two vertically coupled cavities. The top passive cavity contains 2 graphene flakes that are used to control the resonant behavior of the dual cavity structure while the bottom active cavity contains multiquantum well gain material. Our analysis reveals that the optical reflectivity of the dual cavity structure exhibits switchable high-Q resonance. At low optical input, the resonance is governed by the active bottom cavity where the resonance exhibits amplification, and at a higher optical input the resonance is governed by the passive top cavity where the resonance exhibits absorption. We show that this feature can be utilized to realize efficient all-optical switching with contrast ratio as high as 53 dB. The effect of detuning the wavelength of the pump and probe signals as well as changing the graphene chemical potential on the switching behavior is numerically studied and an analytical model has been derived. [ABSTRACT FROM AUTHOR]