# Broadband enhancement of the magneto-optical activity of hybrid Au loaded Bi:YIG

## TL;DR

This study demonstrates that embedding gold nanoparticles in Bi:YIG films significantly enhances their magneto-optical activity across a broad spectrum, due to near-field plasmonic interactions, enabling tailored magneto-optical device design.

## Contribution

It reveals the mechanism behind broadband magneto-optical enhancement in hybrid Au-loaded Bi:YIG, combining experimental and simulation insights.

## Key findings

- Gold nanoparticles cause broadband magneto-optical enhancement.
- Near-field interactions enable cross-talking of localized plasmon resonances.
- Results facilitate on-demand design of hybrid magneto-optical devices.

## Abstract

We unravel the underlying near-field mechanism of the enhancement of the magneto-optical activity of bismuth-substituted yttrium iron garnet films (Bi:YIG) loaded with gold nanoparticles. The experimental results show that the embedded gold nanoparticles lead to a broadband enhancement of the magneto-optical activity with respect to the activity of the bare Bi:YIG films. Full vectorial near- and far-field simulations demonstrate that this broadband enhancement is the result of a magneto-optically enabled cross-talking of orthogonal localized plasmon resonances. Our results pave the way to the on-demand design of the magneto-optical properties of hybrid magneto-plasmonic circuitry.