Cooperative resonance linewidth narrowing in a planar metamaterial

TL;DR

This paper explains how cooperative effects in a metamaterial array cause spectral linewidth narrowing, with potential for enhanced effects in low-loss media, based on theoretical analysis of experimental observations.

Contribution

It provides a theoretical explanation for spectral linewidth narrowing in metamaterials due to cooperative resonator interactions, highlighting the influence of lattice spacing and losses.

Findings

Linewidth narrowing depends on array size and spacing.

Cooperative response explains experimental spectral collapse.

Reduced ohmic losses can enhance narrowing effects.

Abstract

We theoretically analyze the experimental observations of a spectral line collapse in a metamaterial array of asymmetric split ring resonators [Fedotov et al., Phys. Rev. Lett. 104, 223901 (2010)]. We show that the ensemble of closely-spaced resonators exhibits cooperative response, explaining the observed system-size dependent narrowing of the transmission resonance linewidth. We further show that this cooperative narrowing depends sensitively on the lattice spacing and that significantly stronger narrowing could be achieved in media with suppressed ohmic losses.