Nanoscale Vector Magnetometry with a Fiber-Coupled Diamond Probe

A nanoscale vector magnetometer is demonstrated by integrating a microfabricated diamond probe with a nanopillar on top of a single-mode optical fiber. Based on the recently developed self-aligned patterning techniques, & AP;80 nitrogen vacancies are concentrated at a 100 nm(2) area at the center of nanopillars to maximize the excitation and collection efficiencies. The spatial resolution of such a fiber-coupled diamond magnetometer can reach 100 nm for the first time with a sensitivity of 11.27 & mu;T/Hz$\sqrt {{\mathrm{Hz}}} $ for DC magnetic field sensing. In addition, the probe can provide deterministic oriented diamond nanopillars for simplified vector magnetometry. This fiber-coupled diamond probe is applied to demonstrate the magnetic field imaging of charged electrodes in a confined box. These results mark a decisive step toward fiber-based applications with nanoscale vector magnetometry capabilities.