Real-time Terahertz Wave Channeling via Multifunctional Metagratings: A Sparse Array of All-Graphene Scatterers

Abstract

Acquiring full control over a large number of diffraction orders can be strongly attractive in the case of realizing multifunctional devices such as multichannel reflectors. Recently, the concept of metagrating has been introduced which enables obtaining the desired diffraction pattern through a sparse periodic array of engineered scatterers. In this letter, for the first time, a tunable all-graphene multichannel meta-reflector is proposed for operating at terahertz (THz) frequencies. In the supercell level, the designed metagrating is composed of three graphene ribbons of different controllable chemical potentials which can be regarded as a five-channel THz meta-reflector. Several illustrative examples have been presented in which by choosing proper distribution of DC voltages feeding the ribbons, our design can realize different intriguing functionalities such as anomalous reflection, retro-reflection, and three-channel power splitting within a single shared aperture and with high efficiency. This work paves the way toward designing highly-efficient and tunable THz multichannel meta-reflectors with many potential applications in photonics and optoelectronics.