Graphene-based terahertz modulations enhanced with hollow metallic structures

To enhance the modulation of the terahertz wave in graphene based modulators, the hollow metallic structures are proposed in our works. With the field localization and enhancement raised by the resonant of the hollow metallic structures, the interaction between the graphene and the terahertz wave is enhanced. It leads to the modulation enhanced when the conductance of graphene is tuned by applied voltage. The samples with hollow square ring array structure and hollow H-cross array structure is discussed with simulations and experiments. The results indicate that the maximum modulation enhancement is achieved near the resonant frequencies.