High sensitivity optical Faraday-magnetometry with intracavity electromagnetically induced transparency

TL;DR

This paper proposes a cavity QED system utilizing electromagnetically induced transparency to enhance the sensitivity of optical Faraday magnetometry, achieving femtotesla-level detection with multi-atom ensembles.

Contribution

It introduces a novel multiatom cavity QED approach that significantly improves magnetic field sensitivity through collective atom-cavity interactions and multiphoton measurements.

Findings

Sensitivity inversely proportional to atom number with single photon input

Achieved sensitivity of 0.7(5) nT/√Hz with single photon

Enhanced sensitivity to 4.7(9) fT/√Hz using multiphoton measurement

Abstract

We suggest a multiatom cavity quantum electrodynamics system for the weak magnetic field detection based on Faraday rotation with intracavity electromagnetically induced transparency. Our study demonstrates that the collective coupling between the cavity modes and the atomic ensemble can be used to improve the sensitivity. With single probe photon input, the sensitivity is inversely proportional to the number of atoms, and the sensitivity with 0.7(5)~nT/$\sqrt{\rm Hz}$ could be attained. With multiphoton measurement, our numerical calculations show that the magnetic field sensitivity can be improved to 4.7(9)~fT/$\sqrt{\rm Hz}$.