Three-axis closed-loop optically pumped magnetometer operated in the SERF regime.

Area of Science:

• Atomic Physics
• Magnetometry
• Optics

Background:

• Optically pumped magnetometers (OPMs) are crucial for sensitive magnetic field detection.
• Traditional OPMs often face limitations in dynamic range and bandwidth.
• Three-axis magnetic field measurement is essential for various applications.

Purpose of the Study:

• To propose and characterize a novel three-axis closed-loop optically pumped magnetometer.
• To enhance the sensitivity, dynamic range, and bandwidth of OPMs.
• To demonstrate the robustness of the magnetometer in complex environments.

Main Methods:

• Utilizing two orthogonal laser beams for pumping and probing alkali metal atoms.
• Implementing a closed-loop feedback system for magnetometer operation.
• Employing modulation fields at 10 kHz (x, y) and 6 kHz (z) for enhanced performance.

Main Results:

• Achieved a three-axis sensitivity of approximately 30 fT/√Hz.
• Significantly improved the dynamic range from ±5 nT to ±150 nT.
• Increased the operational bandwidth from ~100 Hz to over 2 kHz.

Conclusions:

• The proposed three-axis closed-loop OPM offers high sensitivity and robustness.
• The enhanced dynamic range and bandwidth enable new applications.
• This magnetometer is suitable for biomagnetic measurements, MRI, and fundamental physics research.