Towards the study of low-magnetic field sensors using optically pumped magnetometer

Yi-Hsuan Chen^1,2*, Jia-You Liu¹, Yi-Hsin Chen¹

¹Department of Physics, National Sun-Yat Sen University, Kaohsiung, Taiwan
²Metal Industries Research and Development Centre, Kaohsiung, Taiwan

* Presenter:Yi-Hsuan Chen, email:yschen222@gmail.com

We investigate the operation of alkali metal-optically pumped magnetometers (OPMs) using a single-beam scheme. By simulating the interactions between spin polarization, magnetic fields, and optical pumping intensity, we gained insights into the underlying atomic spin dynamics. The experimental setup, including a Rb glass cell inside a μ-metal shield and magnetic modulation by coils, is used to detect low magnetic fields through a lock-in amplifier. However, challenges such as self-frequency locking caused by pressure broadening were encountered, which reduced system performance. These issues highlight critical considerations for the development of high-sensitivity, commercial OPM systems. We aim to integrate this sensor to 10 cm³ and address the challenges involved in optimization to achieve a sensitivity of approximately 15 fT/√Hz, which is necessary for the applications.

Keywords: Optically pumped magnetometer, atomic sensor, Zeeman effect