High-Precision Mapping of Diamond Crystal Strain Using Quantum Interferometry

Crystal strain variation imposes significant limitations on many quantum sensing and information applications for solid-state defect qubits in diamond. Thus, precision measurement control of diamond crystal is a key challenge. Here, we report measurements with unique set capabilities, including micron-scale spatial resolution, millimeter-scale field-of-view, two order-of-magnitude improvement volume-normalized sensitivity over previous work [1], reaching $5(2) \times 10^{-8}/\sqrt{\rm{Hz}\cdot\rm{\mu m}^3}$ (with spin-strain coupling coefficients representing the dominant systematic uncertainty). We use strain-sensitive spin-state interferometry ensembles nitrogen vacancy (NV) color centers single-crystal CVD bulk low gradients. This technique provides insensitivity to magnetic-field inhomogeneity from electronic nuclear spin bath, thereby enabling long NV ensemble dephasing times enhanced sensitivity. demonstrate protocol first scanning confocal laser microscope, providing quantitative as well three-dimensional mapping; second wide-field imaging microscope (QDM). Our microscopy enables fast, sensitive characterization material engineering nanofabrication; diamond-based strains applied externally, anvil cells or embedded stress sensors, internally, by damage due particle-induced recoils.