Classical Analogue of Electromagnetically Induced Transparency with a Metal-Superconductor Hybrid Metamaterial

TL;DR

This paper presents a superconducting-metal hybrid metamaterial that mimics electromagnetically induced transparency, enabling significant wave slowdown and tunability for potential telecommunication applications.

Contribution

It introduces a novel planar EIT metamaterial using superconducting Nb and normal-metal Au films, achieving large loss contrast and tunable transparency.

Findings

Large transparency window with enhanced group delay below Nb's critical temperature

Precise control of EIT response through superfluid density adjustments

Potential for high delay-bandwidth products in telecommunication applications

Abstract

Metamaterials are engineered materials composed of small electrical circuits producing novel interactions with electromagnetic waves. Recently, a new class of metamaterials has been created to mimic the behavior of media displaying electromagnetically induced transparency (EIT). Here we introduce a planar EIT metamaterial that creates a very large loss contrast between the dark and radiative resonators by employing a superconducting Nb film in the dark element and a normal-metal Au film in the radiative element. Below the critical temperature of Nb, the resistance contrast opens up a transparency window along with a large enhancement in group delay, enabling a significant slowdown of waves. We further demonstrate precise control of the EIT response through changes in the superfluid density. Such tunable metamaterials may be useful for telecommunication because of their large delay-bandwidth products.