Magnetic-field-dependent photodynamics of single NV defects in diamond: an application to qualitative all-optical magnetic imaging

Magnetometry and magnetic imaging with nitrogen-vacancy (NV) defects in rely on the optical detection of electron spin resonance (ESR). , this technique is inherently limited to magnetic fields that are weak to avoid electron spin mixing. Here we focus on the high off-axis field regime for which spin mixing alters the NV defect spin dynamics. first study in a quantitative manner the dependence of the NV defect optical on the magnetic field vector B. Magnetic-field-dependent-resolved photoluminescence (PL) measurements are compared to a seven-level of the NV defect that accounts for field-induced spin mixing. The model the decreases in (i) ESR contrast, (ii) PL intensity and (iii) level lifetime with an increasing off-axis magnetic field. We next that those effects can be used to perform all-optical magnetic in the high off-axis magnetic field regime. Using a scanning NV defect, we map the stray field of a magnetic hard disk through both PL and lifetime imaging. This all-optical method for high magnetic field at the nanoscale might be of interest in the field of nanomagnetism, samples producing fields in excess of several tens of milliteslas are.