Abstract
Placing a sensor close to the target at the nano-level is a central challenge in quantum sensing. We demonstrate high-spatial-resolution magnetic field imaging with a boron vacancy (VB⁻) defects array in hexagonal boron nitride with a few 10 nm thickness. VB⁻ sensor spots with a size of (100 nm)² are arranged periodically with nanoscale precision using a helium ion microscope and attached tightly to a gold wire. The sensor array allows us to visualize the magnetic field induced by the current in the wire with a spatial resolution beyond the diffraction limit. Each sensor exhibits a practical sensitivity of 73.6 μT/Hz^0.5, suitable for quantum materials research. Our technique of arranging VB⁻ quantum sensors periodically and tightly on measurement targets will maximize their potential.