Multifrequency transverse Faraday effect in single magneto-dielectric microspheres

TL;DR

This paper introduces a magneto-dielectric microsphere that significantly enhances the transverse Faraday effect at multiple wavelengths, offering a compact and efficient alternative to traditional MO devices for nanophotonics and imaging.

Contribution

It demonstrates the potential of a single microsphere to outperform thick magnetic plates and gratings in MO response, with multi-wavelength capabilities and nanoscale size.

Findings

Magneto-optical response can be an order of magnitude stronger than in thick plates.

Microsphere response is comparable to subwavelength gratings but with multi-wavelength operation.

The device's small size and spin-wave support make it suitable for advanced nanophotonic applications.

Abstract

We propose using a single magneto-dielectric microsphere as a device for enhancing the transverse Faraday effect at multiple wavelengths at the same time. Although the diameter of the sphere can be $<1$ $\mu$m, the numerically predicted strength of its magneto-optical (MO) response can be an order of magnitude stronger than in MO devices based on thick magnetic plates. The MO response of a microsphere is also comparable with that of subwavelength magneto-dielectric gratings which, however, operate at a single wavelength and occupy a large area. In contrast to gratings and thick plates, the compact size of the microsphere and its capability to support spin-wave excitations make it suitable for applications in nanophotonics, imaging systems, and magnonics.