A graphene-based broadband terahertz metamaterial modulator

A metamaterial (MM) structure composed of a graphene layer, a SiO2/Si substrate, and a metal pattern layer, which is dynamically tunable is numerically proposed at terahertz (THz) frequencies. This study shows that the modulation of the proposed structure mainly depends on the transmission band between two neighboring resonance dips. Based on this property, a fairly wide modulation bandwidth is realized. Moreover, by adjusting the Fermi level of the graphene layer, a modulation depth of the transmission can reach 91.63% for y-polarized wave and 78.66% for x-polarized wave, respectively. Most importantly, the fabrication of the proposed structure is much easier than reported graphene MM modulators as the graphene monolayer is directly deposited on a substrate. This work may provide a further step in the development of tunable devices, such as broadband transmission modulators and sensors.