Three-Dimensional Inverse Reconstruction of Tiny Magnetic Structures by Quantum Technique

Non-destructive measurement of tiny magnetic structures widely found in precision instruments has been a challenging work. Nitrogen vacancy (NV) is a solid-state quantum sensor that enables fast vector magnetic imaging by optical detection. However, NV magnetic detection results lack information about magnetic anomalies in the perpendicular direction, while the dispersive magnetic field blurs the features of the magnetic source. In this article, we combine optical detection NV magnetic imaging with regularized inversion techniques and propose a dual-observation-plane detection inversion method. We study the relationship between spatial magnetization intensity and observed magnetic induction intensity, and realize 3-D inversion reconstruction of miniature magnetic structures. For the validation experiments, we chose to perform 3-D inverse reconstruction and quantitative analysis of the magnetic structures that break in the middle, which is difficult to detect by traditional methods. The inversion results achieve a spatial resolution of
$40~\mu \text{m}$
in all three directions and a model accuracy of 94.4% at 20 iterations, providing a new solution for magnetic structure detection.