Electrical modulation of high-Q guided-mode resonances using graphene

Abstract

Subwavelength dielectric resonators have been demonstrated to provide an authentic platform to excite high-Q resonances in flat optics. Here, we present a strategy to modulate the high-Q resonances electrically using graphene. In the proposed strategy, the high-Q resonance is invoked through the use of a lateral guided-mode resonance that is spectrally aligned with a vertical thin film interference, while graphene is employed to engineer the overall absorption rate. This configuration allows for near unity modulations in both the transmission and the reflection simultaneously. Theoretical analysis shows that the excitation of the high-Q guided-mode resonance is dictated by the electrically tunable interband absorption in graphene while the radiative coupling channel remains intact. In particular, it is shown that the electrical modulation of the high-Q guided-mode resonance facilitates remarkably efficient light modulation without being limited by the graphene quality.