We present a novel wide-field imaging technique to image vortices in type-II superconductors. We acquire the images using ensembles of NV centers in diamond. By using microfabricated diamond plates we reduce the superconductor-NV distance to less than one µm, which allowed us to study the stray magnetic field of vortices in a Type-II superconductor.
https://arxiv.org/abs/1803.01957
Caption: Vortices in a type-II superconductor, imaged using NV centers in a widefield microscope.