Self-calibrating vector atomic magnetometry through microwave polarization reconstruction

TL;DR

This paper introduces a self-calibrating method to convert scalar atomic magnetometers into vector magnetometers by reconstructing microwave polarization, enabling precise magnetic field direction measurement using hyperfine transition polarization dependence.

Contribution

The authors develop a self-calibrating technique to determine microwave polarization and measure magnetic field direction, enhancing atomic magnetometry with vector measurement capabilities.

Findings

Successfully determined microwave polarization ellipse using self-calibration.

Measured static magnetic field direction with high accuracy.

Applicable to trapped atoms and atomic vapors alike.

Abstract

Atomic magnetometry is one of the most sensitive ways to measure magnetic fields. We present a method for converting a naturally scalar atomic magnetometer into a vector magnetometer by exploiting the polarization dependence of hyperfine transitions in rubidium atoms. First, we fully determine the polarization ellipse of an applied microwave field using a self-calibrating method, i.e. a method in which the light-atom interaction provides everything required to know the field in an orthogonal laboratory frame. We then measure the direction of an applied static field using the polarization ellipse as a three-dimensional reference defined by Maxwell's equations. Although demonstrated with trapped atoms, this technique could be applied to atomic vapors, or a variety of atom-like systems.