Multi-Objective Optimization for Triaxial Atomic Magnetometer Based on Harmonic Signals

We report a triaxial magnetic field measurement method using the multi-objective optimization algorithms for single-beam atomic magnetometers (AMs). We utilize triaxial magnetic field coils to apply magnetic fields around the AM as a triaxial magnetic field probe vector, which serve as the parameters to be optimized. The first and second harmonic response signals of the AM are simultaneously collected as fitness evaluation values. Driven by the multi-objective optimization algorithm, the probe moves within the feasible solution space until the vector sum of the probe vector and the target magnetic field vector reaches zero. At this point, the fitness evaluation values are minimized, and the probe vector resides at its optimal value. The target magnetic field is obtained from the optimal probe vector. This technology provides support for accurate measurement of triaxial static magnetic fields, e.g. evaluating residual magnetic fields inside magnetic shields and testing magnetic materials.