Electrically switchable and tunable infrared light modulator based on functional graphene metasurface

Abstract Graphene is emerging as an ideal material for new‐generation optoelectronic devices. In this paper, a novel graphene metasurface‐based electrically switchable and tunable infrared light modulator has been proposed and theoretically studied. The functional modulator comprises a monolayer graphene sheet sandwiched in a Fabry–Perot (FP) like nanostructure consisting of a metal reflector, a dielectric spacer, and an ellipse patterned anisotropy antenna layer. As a result of the photon localization effect of the guided‐mode resonance (GMR) in the FP structure, the graphene electroabsorption can be significantly enhanced to enable a high‐performance light modulator. By fine‐tuning the Fermi energy ( E f ) of graphene via controlling its bias‐gate voltage, the proposed modulator can switch between a perfect absorber and a reflective polarization converter of high conversion efficiency (i.e., >90%) at 1550 nm. The conversion mechanism and the geometric dependences of the infrared light modulator have been investigated. We further demonstrated the tunability of the highly‐efficient polarization converter over a broad spectrum by adjusting the real dispersion of E f . Our design concept provides an effective strategy for customizing novel optoelectronic devices by combining an electrically‐tunable 2D material with a functional metasurface.