Research on Magnetic Field Modulation Coils for Manipulating Spin-Polarized Atoms

Quantum current sensors require highly precise magnetic field measurements for power grid monitoring. As a core component, the magnetic field modulation coil must achieve miniaturization while maintaining high magnetic field uniformity. This study focuses on the design, fabrication, and testing of MEMS (Micro-Electro-Mechanical Systems)-based magnetic field modulation coils. The magnetic field produced by the coil was simulated through COMSOL as well as the coil was fabricated by using MEMS technology, and tested on a custom-built SERF magnetometer platform. Results show that the fabricated bi-planar coil achieves a magnetic field non-uniformity of only 2.1% within a 1.5 mm region for the x/y coil, with coil constants of 68.22 nT/mA (x/y direction) and 395.98 nT/mA (z direction). To ensure integration into chip-scale atomic devices, the layout was carefully designed to suppress parasitic magnetic fields introduced by wiring and interconnections. The MEMS process employed copper sputtering, multilayer insulation, and ICP etching to ensure high fidelity in micro-fabrication. These properties satisfy the integration and accuracy requirements of quantum current sensors, offering key technical support for power grid current monitoring.