A polarization-improved dual-beam spin-exchange relaxation-free magnetometer with reflection-assisted pumping

• Published in: Sensors and actuators. A. Physical. 2024-09, Vol.375, p.115523, Article 115523
• Main Authors: Huang, Binyue, Liu, Ying, Li, Renjie, Li, Jiajie, Tang, Junjian, Zhai, Yueyang
• Format: Article
• Language: English
• Subjects: Double-pass pumping; High sensitivity; Optical polarization; Reflective atomic magnetometer; Spin-exchange relaxation-free
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2024.115523

The highly sensitive SERF magnetometers hold exciting prospects for magnetocardiography and magnetoencephalography, and the accuracy of medical measurements depends largely on the performance of the magnetometers. A double-pass configuration is used to obtain uniform polarization and constructed by adding a mirror to retro-reflect the pump light. The transmission model of the reflected light which takes the effect of forward light into account is proposed, and the improved polarization is experimentally verified. The essential operation parameters of the magnetometer are optimized. The theoretical framework is established outlining the relationship between pump power, probe frequency, and signal response, and the optimal values for these parameters are experimentally determined. With the appropriate selection of probe power and operating temperature, the double-pass configuration achieves a sensitivity of 5.81 fT/Hz1/2, a bandwidth of 110 Hz, and represents a 17% improvement in stability compared to the single-pass configuration. The optimized magnetometer exhibits reduced susceptibility to laser conditions and enhanced stability, attributed to the reflection-assisted polarization improvement and better uniformity. This configuration efficiently utilizes the pumping laser, and its miniaturization offers significant benefits for magnetoencephalography and other biomagnetic measurements. [Display omitted] •Highly sensitive magnetometer with reflection-assisted enhancement.•Improved transmission model of the reflected light considering the forward light.•Thorough comparison between single-pass and double-pass SERF magnetometer.•Sensitivity and stability comparison of magnetometers across 16 test conditions.