Multipole generalization of the Witten effect in Mie-resonant photonics

TL;DR

This paper generalizes the Witten effect to oscillating multipole sources in Mie-resonant photonics, revealing hybridized resonances and cross-polarized components that can serve as sensitive probes of axion-like responses.

Contribution

It introduces a theoretical framework for the Witten effect in Mie-resonant systems with multipole sources, highlighting hybridization and spectral features.

Findings

Hybridization of Mie resonances with double peaks

Presence of cross-polarized radiation components

Potential for sensitive detection of axion-like responses

Abstract

We present a generalization of the Witten effect on the case of oscillating multipole sources exciting nonreciprocal sphere with effective axion response. We find that the fields outside of the sphere are presented as a superposition of electric and magnetic multipoles. In addition to appearance of cross-polarized component in the radiation, Mie resonances of the system hybridize with each other, exhibiting characteristic double peaks in Mie spectra observed especially clearly for higher-order multipole resonances. This characteristic feature may provide a sensitive probe of axion-type nonreciprocal responses in Mie-resonant photonics.