Electric and magnetic dipole coupling in near-infrared split ring metamaterial arrays

TL;DR

This study experimentally investigates electric and magnetic dipole interactions in near-infrared split ring resonator metamaterials, revealing how inter-resonator spacing and orientation influence resonance shifts and broadening due to near-field coupling and superradiance.

Contribution

It provides the first detailed experimental analysis of combined electric and magnetic dipole coupling effects in near-infrared SRR metamaterials, supported by a simple theoretical model.

Findings

Resonance shifts depend on SRR orientation and spacing.

Resonance broadening increases with density due to superradiance.

The simple model accurately predicts observed spectral shifts.

Abstract

We present experimental observations of strong electric and magnetic interactions between split ring resonators (SRRs) in metamaterials. We fabricated near-infrared (1.4 $\mu$m) planar metamaterials with different inter-SRR spacings along different directions. Our transmission measurements show blueshifts and redshifts of the magnetic resonance, depending on SRR orientation relative to the lattice. The shifts agree well with a simple model with simultaneous magnetic and electric near-field dipole coupling. We also find large broadening of the resonance, accompanied by a decrease in effective cross section per SRR with increasing density. These effects result from superradiant scattering. Our data shed new light on Lorentz-Lorenz approaches to metamaterials.