Terahertz metallic photonic crystals integrated with dielectric waveguides

TL;DR

This paper explores hybrid metallic-dielectric photonic crystal waveguides for terahertz frequencies, demonstrating improved confinement and reduced loss, with potential for compact terahertz device integration.

Contribution

It introduces a novel hybrid waveguide design using metallic photonic crystals and dielectric films, optimizing terahertz wave confinement and loss characteristics.

Findings

High-order TM modes exhibit higher confinement than fundamental modes.

Optimal loss occurs at 0.68 THz with specific dielectric parameters.

Hybrid waveguides show promise for compact terahertz devices.

Abstract

Compact and low-loss photonic crystal waveguides are critical in integrated terahertz (THz) applications. Compared with pure metal or dielectric photonic crystal waveguides, hybrid (metal-dielectric) integrated waveguides provide a simple way to further improve the field confinement and the propagation loss. In this work, we investigate a hybrid waveguide consisting of metallic photonic crystals and dielectric films in 0.1-1.0 THz. Photonic crystal waveguides based on metal pillar arrays (MPAs) support two resonance modes including the fundamental and high-order transverse magnetic (TM) modes and then form one apparent bandgap in 0.45-0.55 THz. The high-order TM-mode shows higher confinement than the fundamental mode and are thus sensitive to the dielectric film on the MPAs. The propagation loss and field confinement can be optimized by changing the dielectric film thickness and refractive index. The investigation shows that the lowest loss occurs at 0.68 THz because the high-order TM-mode THz waves are tightly confined inside the hybrid waveguide. This work proves that such hybrid waveguides based on metallic photonic crystals are promising to develop as a compact integrated terahertz device.