Precision NV-Diamond Strain Imaging for Directional Dark Matter Detection

We use pulsed quantum sensing protocols for improved strain imaging using ensembles of nitrogen-vacancy (NV) centers in diamond. This work is a step toward assessing feasibility of directional dark matter detection in a diamond-based detector. In such a detector, NV-based strain imaging would localize potential dark matter damage tracks in a micron-size voxel within a millimeter-sized diamond detector segment.  Subsequent superresolution NV spectroscopy or high-resolution x-ray tomography, within the voxel of interest, would reveal required directional information. On the other hand, it is well-known that strain inhomogeneities affect magnetic field sensing--one of the main applications of NV centers. These results could also inform new avenues toward material development, enabling higher precision magnetometry. We have applied these methods to a variety of diamond samples grown under different conditions, to characterize the strain distribution and suitability for dark matter detection.  Here, we present our latest results and outlook for future improvements.