Experimental Study of Terahertz Surface Wave Field on Metallic and Composite Graphene Films

Plasmonic components for wired and wireless (6G) communication systems, as well as sensor devices in the terahertz frequency range, are now under active development. This stimulates research on materials for integral plasmonic elements that ensure optimal characteristics of information carriers, namely surface plasmon polaritons, which have energy losses and the penetration depth of the SPP field into the air. This work presents the results of experimental studies on the penetration depth of a terahertz surface plasmon polariton field on metallic and composite graphene films. On metal, the penetration depths were found to be an order of magnitude lower than the values predicted by the Drude model for a bulk metal. The penetration depth of the surface plasmon polariton field into the dielectric depended on both the conductivity of the conducting layer and its roughness: it decreased with lower conductivity and increased roughness. Composite graphene films demonstrated high localization of the surface plasmon polariton field, which is of interest for THz sensor devices.