A Voigt effect based 3D vector magnetometer

TL;DR

This paper introduces a novel Voigt effect-based method for 3D vector magnetic field measurement using alkali atoms, capable of high sensitivity in various environments with a simple setup.

Contribution

The authors develop a dispersive detection technique utilizing the Voigt effect to measure all three magnetic field components with high sensitivity and simple geometry.

Findings

Achieved sub-picotesla sensitivity for all three components.

Applicable to both cold and hot atomic gases in shielded and unshielded environments.

Simple single-axis beam geometry suitable for miniaturized sensors.

Abstract

We describe a method to dispersively detect all three vector components of an external magnetic field using alkali atoms based on the Voigt effect. Our method relies on measuring the linear birefringence of the radio frequency dressed atomic medium via polarization homodyning. This gives rise to modulated polarization signals at the first and second harmonic of the dressing frequency. The vector components of the external magnetic field are mapped onto the quadratures of these harmonics. We find that our scheme can be utilised in both cold and hot atomic gases to detect such external fields in shielded and unshielded environments. In the shielded hot vapour case we achieve field sensitivities well below 1~pT$/\sqrt{\textrm{Hz}}$ range for all 3 vector components, using pump-probe cycles with 125 Hz repetition rate, and limited by the short coherence time of the cell. Finally, our scheme has a simple single axis beam geometry making it advantageous for miniature magnetic field sensors.