Cavity magnon polariton based precision magnetometry

TL;DR

This paper demonstrates how cavity magnon polaritons, hybrid photon-magnon quasiparticles, can be used to develop highly sensitive, quantum-limited magnetometers for detecting oscillating magnetic fields with potential applications in precision magnetometry.

Contribution

It introduces novel spin-magnetometers based on cavity magnon polaritons, leveraging their ability to convert magnetic excitations into electromagnetic signals for enhanced sensitivity.

Findings

Achieved quantum-limited sensitivity in magnetometry.

Developed two types of cavity magnon polariton-based spin-magnetometers.

Demonstrated effective detection of oscillating magnetic fields.

Abstract

A photon-magnon hybrid system can be realised by coupling the electron spin resonance of a magnetic material to a microwave cavity mode. The quasiparticles associated with the system dynamics are the cavity magnon polaritons, which arise from the mixing of strongly coupled magnons and photons. We illustrate how these particles can be used to probe the magnetisation of a sample with a remarkable sensitivity, devising suitable spin-magnetometers which ultimately can be used to directly assess oscillating magnetic fields. Specifically, the capability of cavity magnon polaritons of converting magnetic excitations to electromagnetic ones, allows for translating to magnetism the quantum-limited sensitivity reached by state-of-the-art electronics. Here we employ hybrid systems composed of microwave cavities and ferrimagnetic spheres, to experimentally implement two types of novel spin-magnetometers.