Multifunctional Fano resonance modulator with graphene-based double-layer independent gratings

Abstract

Fano resonance is based on a plasmonic metasurface and has many applications in various fields. In this paper, we propose an independently adjustable graphene-based double-layer grating structure. We control multiple Fano resonances at different wavelengths and bandwidths by regulating the Fermi level thanks to the preeminent characteristic of graphene. Here, the equivalent resonator coupled-mode method is used to better describe the Fano resonance of this designed structure adequately, and the transmission spectra fit well. The functional switch could be achieved at different wavelengths by using Fano resonance. We can obtain excellent group refractive index of this designed structure, which means it has superior applications in slow light. The effect of the refractive index of the dielectric layer on the sensing performance is researched so that the structure has a good application in sensors. Furthermore, we look forward to making potential contributions to fabricate integrated optical sensors and devices based on those elaborately designed structures.