Plasmon induced transparency in an air-dielectric grooved parallel plate terahertz waveguide

In this article, we examine plasmon induced transparency (PIT) effect in a parallel plate waveguide (PPWG) comprising of two similar pyramidal shaped grooves. One of the grooves is filled with air, while the other is filled with a dielectric material whose refractive index can be varied. The resonant frequencies corresponding to the air and dielectric grooves in the proposed configuration results in the transparency window which can be modulated with the refractive index of the dielectric material. The approach provides flexibility to actively control transparency effect in a waveguide configuration without changing physical dimensions. We examined field profiles in the transparency region to clearly depict the PIT effect. We have employed an analytical model based upon the three-level plasmonic model to validate our numerical findings. Further, we examined the switching and tunability of transparency effect by including silicon layers between the grooves whose conductivity can be varied. Actively tunable response in plasmon induced transparency effect in terahertz waveguides can be significant in the construction of terahertz active components.