Circulating cavity magnon polaritons

TL;DR

This paper predicts and confirms the existence of circulating unidirectional magnon polariton states in a microwave cavity loaded with magnets, demonstrating controlled directional microwave beams through phased antenna arrays.

Contribution

It introduces a fully analytical model for circulating magnon polaritons and validates it with realistic numerical simulations, highlighting new ways to control microwave beam direction and intensity.

Findings

Circulating unidirectional magnon polariton states are predicted.

A phased antenna array can focus power into a directed microwave beam.

The model's predictions are confirmed by finite-element simulations.

Abstract

We predict magnon polariton states circulating unidirectionally in a microwave cavity when loaded by a number of magnets on special lines. Realistic finite-element numerical simulations, including dielectric, time-dependent and non-linear effects, confirm the validity of the approximations of a fully analytical input-output model. We find that a phased antenna array can focus all power into a coherent microwave beam with controlled direction and an intensity that scales with the number of magnets.