Sensitive and accurate quantum magnetometry for GNSS-denied positioning, critical national infrastructure, and magnetic anomaly detection

Optically pumped magnetometers (OPMs) exploiting alkali metal vapours for accurate, precise magnetometry have benefited from improvements in components and techniques in recent years. Microfabrication of alkali cells and chip-scale lasers allow mass-production of compact sensors, and feedback an spin-preparation techniques, such as light-narrowing, allow enhanced performance, comparable with cryogenic SQUID magnetometers. I will introduce two OPM modalities developed at Strathclyde for geomagnetic operation- the digital alkali-spin maser and geophysical free-precession magnetometer. I will discuss the potential impacts of using these sensors for geophysical applications, including Global Navigation Satellite System (GNSS)-denied positioning, monitoring of space weather and magnetic anomaly detection. I will present developments in microfabrication and digital signal processing which will enable their widespread adoption.