High optical magnetism of dodecahedral plasmonic meta-atoms

TL;DR

This paper demonstrates that dodecahedral plasmonic meta-atoms exhibit significantly enhanced optical magnetic responses, surpassing disordered clusters, through a novel bottom-up synthesis and experimental validation.

Contribution

The study introduces a new dodecahedral nano-cluster design inspired by Platonic solids, achieving stronger optical magnetism than previous disordered structures.

Findings

Magnetic to electric response ratio is three times higher in dodecahedral clusters.

Numerical simulations agree with experimental measurements.

Dodecahedral structures enhance optical magnetic response in visible light.

Abstract

The generation in artificial composites of a magnetic response to light comparable in magnitude with the natural electric response, may offer an invaluable control parameter for a fine steering of light at the nanoscale. In many experimental realizations however, the magnetic response of artificial meta-atoms is too weak so that there is a need for new designs with increased magnetic polarizability. Numerical simulations show that geometrical plasmonic nanostructures based on the ideal model of Platonic solids are excellent candidates for the production of strong optical magnetism in visible light. Inspired by this model, we developed a bottom-up approach to synthesize plasmonic nano-clusters made of twelve gold patched located at the center of the faces of a dodecahedron. The scattering of the electric and magnetic dipole induced by light are measured across the whole visible range. The ratio of the magnetic to electric response at resonance is found three times higher than its counterpart measured on disordered plasmonic clusters (plasmonic raspberries) of the same size. Numerical simulations confirm the experimental measurements of the magnetic response.