Coupling of plasmon and photon modes in a graphene-based multilayer structure

We propose a graphene-based plasmonic heterostructure in which a new class of plasmon polariton modes can be realized via fundamental coupling of conventional graphene plasmons (GPs) and spoof surface plasmons or radiation modes. We name these electromagnetic modes coupled graphene plasmon polaritons (CGPPs). It is found that the properties of the CGPPs can be tuned by the geometry of the heterostructure, the material used to fill the holes, and the electron density in graphene. Most interestingly, we show that it is possible to achieve CGPPs with about 10 times enhancement of wave localization or about 300 times enhancement of propagation length, compared to usual GPs through varying device parameters. These features can be applied to tunable terahertz and infrared plasmonic devices.