Enhanced Transmission of Terahertz Radiation through Periodically Modulated Slabs of Layered Superconductors

TL;DR

This paper predicts that periodically modulated layered superconductor slabs can significantly enhance terahertz radiation transmission through diffraction and resonance of eigenmodes, enabling high transmittance peaks.

Contribution

It introduces a novel mechanism for enhanced terahertz transmission via diffraction and waveguide mode resonance in layered superconductor slabs.

Findings

Resonance peaks with near-unity transmittance observed at specific angles.

Enhanced transmission due to excitation of waveguide modes rather than surface waves.

Transmission depends on the crossing of dispersion curves for diffracted waves and WGMs.

Abstract

We predict the enhanced transmissivity of modulated slabs of layered superconductors for terahertz radiation due to the diffraction of the incident wave and the resonance excitation of the eigenmodes. The electromagnetic field is transferred from the irradiated side of a slab of layered superconductor to the other one by excited waveguide modes (WGMs) which do not decay deep into the slab, contrary to metals, where the enhanced light transmission is caused by the excitation of the evanescent surface waves. We show that a series of resonance peaks (with $T \sim 1$) can be observed in the dependence of the transmittance $T$ on the varying incidence angle $\theta$, when the dispersion curve of the diffracted wave crosses successive dispersion curves for the WGMs.