Surface plasmon modes in self-biased coupled graphene-coated wires

Plasmonic modes supported by a pair of self-biased coupled graphene-coated wires (GCW) are studied in detail. The proposed biasing structure enables the reconfiguration of the guided surface waves without additional gating electrodes, inducing a spatially variant conductivity that is calculated analytically. The eigenmode study of the structure reveals the presence of two fundamental modes with odd and even symmetry, which concentrate the fields in the gap between the wires and in the outer perimeter of the wires, respectively. The reconfigurable multimode behaviour and strong field enhancement induced by this structure may enable efficient light harvesting and nanofocusing in THz sensing systems.