Probing magnetic noise from portable sensor components using a zero-field optically pumped magnetometer

Zero-field optically pumped magnetometers (OPMs), including those operating near the spin-exchange relaxation-free (SERF) regime, provide extremely high sensitivity to small magnetic perturbations and are widely used in high-sensitivity atomic magnetometry. At such high sensitivities, even weak stray magnetic fields and magnetic noise originating from nearby components can significantly perturb atomic spin dynamics and limit sensor performance, particularly in compact OPM architectures. We realize a zero-field OPM and use it as a sensitive test platform to probe magnetic noise from sensor components used in the development of portable OPMs. Under active three-axis magnetic-field nulling inside a magnetic shield, optical components are placed in close proximity to a rubidium vapor cell. Magnetic noise from the components is probed through changes in the dispersion curve of the zero-field OPM and analyzed using theoretical calculations of the dispersion response.