Graphene-metamaterial hybridization for enhanced terahertz response

Improving the interaction of graphene with terahertz (THz) waves in experiment - through experimental measurement is a challenge for THz detectors, modulators, and other THz photonic components based on graphene. Hybridization of graphene with metamaterials leads to a strong THz response enhancement. Here, we observed maximum enhancement of 33.0% in non-resonant region and 23.8% in resonant region with the hybridization of graphene and metamaterials in experiment. A coupling model as well as numerical calculation has been carried out to fully investigate the influence of this coupling. The results suggest that there exists an exponential relationship between coupling strength and THz response in both resonant and non-resonant region, while the resonant frequency shift shows a linear growth with coupling strength. The bandwidth of the resonance shows exponential increasing with the damping constant. Correspondingly, the numerical calculation shows the similar dependency with the electrical conductivity of the graphene overlayer. This suggests a higher conductivity for stronger coupling. Substrates could also bring the remote phonon scattering, charge transfer, and dielectric effect, which show the influence such as low dielectric constant for high coupling. (C) 2014 Elsevier Ltd. All rights reserved.