Abstract

In this paper, a metallic terahertz (THz) plasmonic waveguide comprising subwavelength scale pillars is proposed. The pillars are periodically arranged in one dimension and are assumed to be metallic; on the top of the pillars, dielectric material is deposited. The fundamental guided resonant mode properties of the waveguide are comprehensively examined with and without dielectric material. Furthermore, guided modes are examined while varying the refractive index value (${n}$) of the dielectric material, and it is observed that resonant modes supported by the waveguide strongly depend on ${n}$ value of dielectrics. The dispersion relations of the guided modes are analyzed to ensure the plasmonic response. To support the numerical results, a Drude model is employed to fit the real and imaginary parts of the complex dielectric function for the proposed waveguide design. The group velocity of the fundamental guided terahertz mode is calculated in order to investigate slow-light properties of the terahertz wave. Additionally, the phase of transmission output and electric field profiles are studied in support of slow-light phenomena. The slow-light phenomenon using a dielectric–metal-based plasmonic waveguide could be very useful in construction of terahertz buffers, storage devices, terahertz sensors, detectors, etc.

© 2020 Optical Society of America

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