Implementation of a nitrogen-vacancy micro-pillar array in diamond for a quantum imaging application with improved sensitivity

In this Letter, we have fabricated a diamond pillar array device from an in-situ grown nitrogen-vacancy (NV)-doped diamond epi-layer. The device can achieve an imaging function of current-induced magnetic fields thanks to the elaborately patterned circular truncated cones. Through a simple continuous-wave optically detected magnetic resonance scheme as a demo, a 7-fold improvement in fluorescence collection intensity, a 40% narrower line-width, and a 2-fold improvement in the contrast have been achieved on the device, leading to a considerable improvement on the magnetic sensitivity. With these improvements, the device can resolve a line current one order of magnitude smaller than the non-patterned NV layer on diamond, demonstrating artificially patterned NV ensembles being implemented to the magnetic field imaging of an external sample. It will promote wider adoption of 2D sensing/imaging using the NVs.