Stand-off magnetometry with directional emission from sodium vapors

TL;DR

This paper introduces a novel stand-off magnetometry technique using mirrorless lasing in sodium vapors, enabling directional emission of light for improved remote magnetic field measurements in various environments.

Contribution

It demonstrates for the first time that mirrorless lasing can produce directional emission from sodium vapors, enhancing stand-off magnetometry capabilities.

Findings

Successfully detected sodium spin precession signals remotely.

Achieved scalar magnetometry in Earth's magnetic field range.

Demonstrated potential for long-baseline magnetic sensing.

Abstract

Stand-off magnetometry allows measuring magnetic field at a distance, and can be employed in geophysical research, hazardous environment monitoring, and security applications. Stand-off magnetometry based on resonant scattering from atoms or molecules is often limited by the scarce amounts of detected light. The situation would be dramatically improved if the light emitted by excited atoms were to propagate towards the excitation-light-source in a directional manner. Here, we demonstrate that this is possible by means of mirrorless lasing. In a tabletop experiment, we detect free-precession signals of ground-state sodium spins under the influence of a magnetic field by measuring backward-directed light. This method enables scalar magnetometry in the Earth field range, that can be extended to long-baseline sensing.