Plasmon hybridization in graphene metamaterials

Plasmon hybridization in a stacked pair of graphene ribbons is investigated at terahertz frequencies. We fabricated and characterized an array of graphene ribbons on a heavily-doped Si substrate with a SiO₂ gap layer in between. The interaction between graphene plasmons and their mirror images in the substrate forms a coupled system, mimicking a graphene ribbon pair, thereby dramatically modifies the mode profiles and resultant spectral responses. Magnetic plasmon resonances arising from the plasmon hybridization are demonstrated at terahertz frequencies. The corresponding numerical simulations reveal the important resonant behavior of structured graphene and their hybridized systems.