Wide-field AC Magnetic Field Imaging using Continuous-Wave Optically Detected Magnetic Resonance of Nitrogen-Vacancy Centers in Diamond

摘要

A promising candidate for room temperature highly-sensitive magnetometry with high spatial resolution is the nitrogen-vacancy (NV) center in diamond. Scanning confocal microscopic techniques are typically used for conventional magnetometry. However, long measurement times are required to achieve a wide observation area and/or high sensitivity. There are advantages of using CCD/CMOS cameras to enable wide field of view and rapid acquisition time by detecting signals from NV centers many camera pixels simultaneously, so called wide-field imaging. For cameras with slow response time, it is suitable to use continuous-wave optically detected magnetic resonance (CW-ODMR) to perform magnetic field imaging. However, by using conventional CW-ODMR techniques, only DC or low-frequency AC magnetic fields can be detected. Our group has recently developed a new measurement protocol using CW-ODMR to detect high-frequency AC magnetic fields by taking advantage of the zero-field splitting of the spin triplet states of the NV center. By further applying a DC magnetic field the contribution from the different crystallographic axes of the NV center can be separated and focusing on one preferential axis the sensitivity can be increased. These techniques are compatible imaging techniques using CCD cameras.