Optimizing Broadband Terahertz Modulation with Hybrid   Graphene/Metasurface Structures
  We demonstrate efficient terahertz (THz) modulation by coupling graphene strongly with a broadband THz metasurface device. This THz metasurface, made of periodic gold slit arrays, shows near unity broadband transmission, which arises from coherent radiation of the enhanced local-field in the slits. Utilizing graphene as an active load with tunable conductivity, we can significantly modify the local-field enhancement and strongly modulate the THz wave transmission. This hybrid device also provides a new platform for future nonlinear THz spectroscopy study of graphene. 
S.-F. Shi, B. Zeng, H.-L. Han, X. Hong, H.-Z. Tsai, H. S. Jung, A.   Zettl, M. F. Crommie, F. Wang
cond-mat.mes-hall