Channel hybrid plasmonic modes in dielectric-loaded graphene groove waveguides

Dielectric-loaded graphene groove waveguide (DLGGW) structure is designed and the channel hybrid plasmonic modes are investigated in the terahertz domain. The proposed structure could effectively suppress the mode field confinement with relative low transmission loss due to the strong coupling between the dielectric mode and the channel graphene plasmonic mode. A typical propagation length is 37.8μm, and optical field is confined into an ultra-small area of approximately 52μm2 at 1.5 THz. By changing the size of cylinder, the angle of the graphene groove, and the thickness of dielectric coating layer, the compromise between confinement and loss could be balanced flexibly. Unlike plasmons in noble metals, the propagation loss in DLGGW structure could be tuned by the graphene conductivity. Moreover, because of the imaginary part of graphene conductivity being positive, the proposed waveguide can propagate in a large terahertz frequency regime. This waveguide shows great applications in optical integrated devices, such as detectors, sensors and spectroscopy.