A Chiral Inverse Faraday Effect Mediated by an Inversely Designed Plasmonic Antenna

TL;DR

This paper introduces a chiral inverse Faraday effect using an inversely designed plasmonic antenna, enabling selective magnetic field generation with specific light helicities, advancing ultrafast magnetic control technologies.

Contribution

The study demonstrates a novel chiral inverse Faraday effect mediated by a specially designed plasmonic nanostructure, allowing helicity-dependent magnetic field generation.

Findings

Magnetic field of 500 mT generated for one light helicity.

Mirror structure produces opposite effect for opposite helicity.

Potential applications in ultrafast magnetic data manipulation.

Abstract

The inverse Faraday effect is a magneto-optical process allowing the magnetization of matter by an optical excitation carrying a non-zero spin or orbital moment of light. This phenomenon was considered until now as symmetric; right or left circular polarizations generate magnetic fields oriented in the direction of light propagation or in the counter-propagating direction. Here, we demonstrate that by manipulating the spin density of light in a plasmonic nanostructure, we generate a chiral inverse Faraday effect, creating a strong magnetic field of 500 mT only for one helicity of the light, the opposite helicity producing this effect only for the mirror structure. This new optical concept opens the way to the generation of magnetic fields with unpolarized light, finding application in the ultrafast manipulation of magnetic domains and processes, such as spin precession, spin currents and waves, magnetic skyrmion or magnetic circular dichroism, with direct applications in data storage and data processing technologies.