Electrically switchable and tunable infrared light modulator based on functional graphene metasurface
Wei Luo, Syeda Aimen Abbasi, Shaodi Zhu, Xuejin Li, Ho‐Pui Ho, Wu Yuan
Abstract
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.