Magneto-Optical Activity in High Index Dielectric Nanoantennas

TL;DR

This paper theoretically investigates the magneto-optical activity of high-index dielectric nanospheres, revealing that magnetic resonances dominate polarization conversion, contrasting with plasmonic particles.

Contribution

It demonstrates that in dielectric nanospheres, magneto-optical response is primarily governed by magnetic resonances, unlike electric effects in plasmonic systems.

Findings

Magneto-optical activity is linked to electromagnetic field interaction within the nanospheres.

Magnetic resonances (dipolar and quadrupolar) dominate the magneto-optical response.

Electric resonances have minimal impact on the magneto-optical behavior.

Abstract

The magneto-optical activity, namely the polarization conversion capabilities of high-index, non-absorbing, core-shell dielectric nanospheres is theoretically analyzed. We show that, in analogy with their plasmonic counterparts, the polarization conversion in resonant dielectric particles is linked to the amount of electromagnetic field probing the magneto-optical material in the system. However, in strong contrast with plasmon nanoparticles, due to the peculiar distribution of the internal fields in resonant dielectric spheres, the magneto-optical response is fully governed by the magnetic (dipolar and quadrupolar) resonances with little effect of the electric ones.