Ultrastrongly-coupled and Directionally-nonreciprocal Magnon-polaritons in Magnetochiral Metamolecules

TL;DR

This paper reports the experimental realization of magnon-polaritons with ultrastrong coupling and directional nonreciprocity in a magnetochiral metamolecule at room temperature, advancing hybrid quantum systems and synthetic gauge fields.

Contribution

It demonstrates for the first time ultrastrongly-coupled, nonreciprocal magnon-polaritons in a symmetry-breaking metamolecule at room temperature.

Findings

Ultrastrong coupling achieved between magnons and microwave photons.

Directional nonreciprocity observed in the magnon-polariton system.

Theoretical and numerical models accurately reproduce experimental results.

Abstract

We experimentally demonstrate magnon-polaritons with ultrastrong coupling and directional nonreciprocity in a metamolecule lacking time-reversal and space-inversion symmetries at room temperature. These experimental results are reproduced well via numerical simulations and theoretical consideration. Ultrastrong coupling is due to a direct interaction of magnons in the magnetic meta-atom with microwave photons confined in the chiral meta-atom as a resonator. Our results reveal a crucial step in identifying deepstrongly-coupled and optically-moving magnon-polaritons for hybrid quantum systems, synthetic gauge fields, and quasi-particle ``chemistry'' using metamaterials.