Mitigation of sensor inhomogeneities to speed up diamond-based wide-field magnetic imaging.

Wide-field magnetometry can be realized by imaging the optically-detected magnetic resonance of diamond nitrogen vacancy (NV) center ensembles. However, sensor inhomogeneities significantly limit the magnetic field sensitivity of these measurements. We report a technique for mitigating NV ensemble inhomogeneities to speed up absolute magnetic imaging which uses a double-double quantum (DDQ) driving scheme. DDQ difference imaging employs four-tone radio frequency pulses to suppress inhomogeneity-induced variations of the resonant response, enabling a linear mapping between the magnetic field projection onto the NV ensemble symmetry axis and changes in the emitted NV photoluminesence intensity. This simple and robust technique expands the application space of diamond NV centers by extending existing NV absolute magnetic sensing techniques to rapid, wide-field imaging.