Probing Terahertz Metamaterials with Subwavelength Optical Fibers

TL;DR

This paper investigates terahertz fiber interactions with frequency selective surfaces, revealing how resonances can be tuned via fiber-metamaterial separation using finite element simulations and band diagram analysis.

Contribution

It introduces a comprehensive analysis of terahertz fiber-metamaterial interactions, linking spectral features to Van Hove singularities and Fano resonances, with tunable parameters.

Findings

Transmission peaks relate to Van Hove singularities.

Spectral features are explained by Fano resonances.

Resonance frequencies and bandwidths are tunable.

Abstract

Transmission through a subwavelength terahertz fiber, which is positioned in parallel to a frequency selective surface, is studied using several finite element tools. Both the band diagram technique and the port-based scattering matrix technique are used to explain the nature of various resonances in the fiber transmission spectrum. First, we observe that spectral positions of most of the transmission peaks in the port-based simulation can be related to the positions of Van Hove singularities in the band diagram of a corresponding infinite periodic system. Moreover, spectral shape of most of the features in the fiber transmission spectrum can be explained by superposition of several Fano-type resonances. We also show that center frequencies and bandwidths of these resonances and, as a consequence, spectral shape of the resulting transmission features can be tuned by varying the fiber-metamaterial separation.