Non-Reciprocal Graphene Gratings Based on Spatiotemporal Modulation

This paper presents a nonreciprocal grating based on graphene strips on top of a dielectric substrate for THz frequencies. Nonreciprocity is achieved by applying a directional temporal modulation with different phases to different graphene strips of the grating. Quite importantly, only three distinct modulation regions are necessary to achieve strong nonreciprocity, relaxing the fabrication requirements. Simulation results show very large isolation with moderate insertion loss for realistic parameters for graphene, making the proposed structure suitable for practical applications at THz frequencies.