Electric dipole-free interaction of visible light with silver metadimers

TL;DR

This paper demonstrates that specially designed silver metadimers can interact with visible light through electric quadrupole and magnetic dipole moments, bypassing the typical electric dipole interaction, leading to unique optical properties.

Contribution

The work introduces a novel meta-atom design where only higher-order multipoles are excited, enabling new optical behaviors in metamaterials.

Findings

Metadimers can be tuned to excite only quadrupole and magnetic dipole moments.

The scattered electromagnetic fields differ fundamentally from those of electric dipoles.

Metamaterials made of these metadimers exhibit unusual optical properties.

Abstract

In subwavelength-sized particles, light-induced multipole moments of orders higher than the electric dipole are usually negligibly small, which allows for the light-matter interaction to be accurately treated within the electric dipole approximation. In this work we show that in a specially designed meta-atom, a disc metadimer, the electric quadrupole and magnetic dipole can be the only excitable multipoles. This condition is achieved in a narrow but tunable spectral range of visible light both for individual metadimers and for a periodic array of such particles. The electromagnetic fields scattered by the metadimers fundamentally differ from those created by electric dipoles. A metamaterial composed of such metadimers will therefore exhibit unusual optical properties.