2024/08/19 by Thomas Schönau, Theo Scholtes, Schönau, Thomas +11 · 2 citations
Engineering · Physics and Astronomy · #Atomic Physics (physics.atom-ph) #Atomic and Subatomic Physics Research #FOS: Physical sciences #Geophysics (physics.geo-ph) #Instrumentation and Detectors (physics.ins-det) #Magnetic Field Sensors Techniques #Magneto-Optical Properties and Applications
paper · pdf · doi:10.48550/arxiv.2408.09915
openalex publication_date 2024/08/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a novel approach allowing an optically pumped magnetometer (OPM) to be operated within Earth's magnetic field as a vector magnetometer whose sensitive axis can be freely defined. This approach enables the measurement of any vector component of the Earth's magnetic field with the same sensitivity. The OPM is realized by a microfabricated cesium vapor cell with nitrogen buffer gas, which is immersed into a homogeneous bias field of about 730 μT. Since this bias field is about one order of magnitude stronger than Earth's magnetic field, it defines the sensitive axis of the OPM. The bias field is generated by solid-state magnets and was designed to exhibit a very low relative inhomogeneity (< 10-4 in relative units) within the vapor cell dimensions as well as a point of vanishing temperature dependence at around 40°C. The OPM utilizes the light narrowing effect, which enables effective suppression of spin-exchange relaxation even in such large magnetic field amplitude. Based on this implementation, we demonstrate a white noise floor of below 60 fT/√(Hz) in the interval between 100 Hz and 600 Hz and a sensor bandwidth of > 2 kHz. Our approach enables unshielded ultrasensitive vectorial measurement capabilities relevant in many important applications.