Study on properties of plasmonic waveguide of graphene-coated nanotube with a dielectric substrate

Abstract

A hybrid plasmonic waveguide structure composed of graphene-coated nanotube with a dielectric substrate is proposed in this paper. Transmission properties of the fundamental mode are studied by the finite element method (FEM). The results reveal that the mode transmission properties are greatly dependent on the nanotube radius and internal–external diameter ratio, gap distance, nanotube permittivity, as well as chemical potential of graphene. Meanwhile, it is compared with the graphene-coated nanowires with a dielectric substrate (Hajati and Hajati in Plasmonics, 2018. https://doi.org/10.1007/s11468-017-0524-2). By optimizing the parameters, the structure could achieve long-range propagation with the propagation length about 12.56 um. Moreover, it could realize deep-subwavelength confinement with the normalized mode area only ~ 10–7 in the mid-infrared (mid-IR). This structure may offer a certain theoretical basis for integrated nanophotonic devices to achieve long-distance transmission in the deep-subwavelength range.