Modeling and analysis of phase characteristics in NMOR atomic magnetometers

Abstract

The NMOR atomic magnetometer enables measurement ranging from zero field to geophysical-scale fields, offering significant advantages in complex magnetic field environment. It achieves precise magnetic field measurement by detecting either amplitude or phase information. However, despite the fact that phase information extraction is more widely in practical applications, current research aimed at developing a comprehensive phase output model remains insufficient. In this paper, we develop a detailed phase information model for the optical modulation NMOR atomic magnetometer, deriving analytical solutions for measurement in geophysical-scale magnetic fields. Experimental results demonstrate that the phase scale factor exhibits a lower attenuation rate compared to the amplitude scale factor, resulting in more stable magnetic field measurement outcomes. Meanwhile, noise analysis identifies magnetic noise and optical power fluctuation-induced noise as the primary factors affecting the sensitivity of the NMOR atomic magnetometer. These findings demonstrate the advantages of phase detection in high-field measurement, providing valuable insights for enhancing the performance and broadening the applications of the NMOR atomic magnetometer.