Non-reciprocal THz components based on spatiotemporally modulated graphene

Abstract

We introduce the concept of magnet-free nonreciprocal graphene components at terahertz (THz) frequencies based on spatiotemporal modulation of graphene conductivity. As an example, we design a fully planar, reconfigurable, plasmonic isolator using a graphene parallel-plate waveguide with timevarying gate voltages that implement the required travellingwave-like perturbation. We envision that this approach will lead to reconfigurable non-reciprocal THz components with unprecedented performance and functionalities, with applications in biosensing, communications, imaging, and detecting devices.

Analytical formulation of spatiotemporal modulated graphene-based waveguides using Floquet-Bloch theory

“…At THz frequencies where , the interband term is negligible 54 , 61 . Furthermore, as all values of modulated chemical potential in this study are considered far from Dirac point, we assume that , which allows to employ Drude form of surface conductivity for the intraband term resulting in: …”