Exceptional Terahertz Wave Modulation in Graphene Enhanced by Frequency Selective Surfaces

In this paper we theoretically and experimentally analyze the design trade-offs in terahertz metamaterial modulators consisting of hybrid graphene/metal stacked structures. In these devices graphene is used as the active medium, whereas a passive metallic frequency selective surface is employed to enhance the light–matter interaction in graphene. When altering the key geometrical structural parameters, we observe a close match between our experiments and theory, showing that it is possible to achieve an optimal trade-off between modulation depth, insertion loss, and speed in these devices. Moreover, a transmission line based compact mathematical model is introduced in order to explain our experimental observations and predict the performance limits in these structures