Study on the plasmonic characteristics of bow-tie type graphene-coated nanowire pair

A novel plasmonic waveguide composed of graphene-coated dielectric bow-tie type nanowire pair is designed in this paper. The finite element method (FEM) is used to study the dependences of the modal performances on the geometry and electromagnetic parameters. Simulation results show that strong enhancement of the optical field can be confined in the gap region formed by the bow-tie type nanowire pair coated by graphene. The minimum value of normalized mode area approaches to an order of 10−7 magnitude. Moreover, it has a good tolerance to practical fabrication errors. Thanks to these excellent optical characteristics, this kind of graphene-based plasmonic waveguide can be used to fabricate various functional optoelectronic devices for the future nanoscale photonic integrated circuits and biosensors.