Terahertz guided mode properties in an internally corrugated plasmonic waveguide

We discuss the terahertz surface plasmon propagation properties in a waveguide comprising of subwavelength scale internally corrugated V-shaped structures. The structures are assumed to be periodically arranged in a thin sheet of metal and ensure plasmonic response of the waveguide. We comprehensively examine the effect of internal corrugations on the plasmonic properties of the guided modes supported by the waveguide. The guided mode properties are found to vary with the internal corrugations of the structures. We observe that multimode propagation can be switched to a single mode as we increase the steps of internal corrugations. The findings are supported with a semi-analytical model that we employ specifically for our geometry. We also analyze the dispersion properties of the fundamental modes under the different steps of corrugations and calculate group velocity in order to understand the slow light behavior of the modes. The results are compared with the waveguides having V-grooves without any internal corrugations. Our study could be significant to understand the role of corrugations along the waveguide as well as within the structures and accordingly their applications in the active and passive plasmonic guided wave devices. Published by AIP Publishing.