We demonstrate microwave-free eddy-current imaging using nitrogen-vacancy centers in diamond. By detecting the eddy-current induced magnetic field of conductive samples, we can distinguish between different materials and shapes and identify structural defects. Our technique allows for the discrimination of different materials according to their conductivity. The sensitivity of the measurements is calculated as 8×105\,S/m\,Hz at 3.5\,MHz, for a cylindrical sample with radius r0\,=\,1\,mm and height h\,=\,0.1\,mm (volume ∼\,0.3\,mm3), at a distance of 0.5\,mm. In comparison with existing technologies, the diamond-based device exhibits a superior bandwidth and spatial resolution. In particular, we demonstrate a flat frequency response from DC to 3.5 MHz and a spatial resolution of 348\,±\,2\,μm.
@article{arxiv.1810.02723,
title = {Eddy-current imaging with nitrogen-vacancy centers in diamond},
author = {Georgios Chatzidrosos and Arne Wickenbrock and Lykourgos Bougas and Huijie Zheng and Oleg Tretiak and Yu Yang and Dmitry Budker},
journal= {arXiv preprint arXiv:1810.02723},
year = {2019}
}