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Compact high-bandwidth single-beam optically-pumped magnetometer for biomagnetic measurement.
Tianbo Wu1, Wei Xiao1,2, Xiang Peng1
1State Key Laboratory of Advanced Optical Communication Systems and Networks, School of Electronics, and Center for Quantum Information Technology, Peking University, Beijing 100871, China.
Biomedical Optics Express
|January 16, 2025
Summary
We developed a high-bandwidth optically-pumped magnetometer (OPM) for measuring fast biomagnetic signals. This novel spin-exchange-relaxation-free (SERF) magnetometer achieves 1 kHz bandwidth, enabling mouse magnetocardiography.
Area of Science:
- Biophysics
- Biomedical Engineering
- Quantum Sensing
Background:
- Optically-pumped magnetometers (OPMs) offer a low-cost, portable alternative to SQUID systems for biomagnetic measurements.
- Miniaturized spin-exchange-relaxation-free (SERF) OPMs traditionally have limited bandwidth (< few hundred Hz), hindering high-frequency signal detection like mouse magnetocardiography (MCG).
Purpose of the Study:
- To introduce a prototype miniaturized single-beam SERF OPM with enhanced bandwidth for biomagnetic signal measurement.
- To overcome the bandwidth limitations of existing SERF OPMs for capturing high-frequency biological signals.
Main Methods:
- Utilized power-broadening effects to reduce spin relaxation time, enabling faster magnetic field response.
- Implemented light power stabilizations to enhance magnetometer sensitivity and stability.
- Developed a single-beam SERF OPM with a bandwidth of approximately 1 kHz.
Main Results:
- Achieved a magnetometer bandwidth of ~1 kHz, significantly exceeding typical SERF OPM capabilities.
- Demonstrated a low noise floor of 30 fT/√Hz.
- Successfully measured mouse magnetocardiography (MCG) signals using the developed OPM.
Conclusions:
- The developed high-bandwidth SERF OPM is suitable for measuring high-frequency biomagnetic signals like mouse MCG.
- Power-broadening is an effective technique for enhancing OPM bandwidth without compromising performance in the high-frequency range.
- This advancement opens new possibilities for portable and cost-effective biomagnetic research.
