High-sensitivity absorption-based magnetometry using Nitrogen-Vacancy centers in diamond*

Precision optical measurements using Nitrogen-Vacancy (NV) centers in diamond have proved useful for numerous applications. Over the last decade, NV center-based magnetometers have made astonishing improvements in sensitivity, due to new understanding of noise sources, improved pulse sequences, and various engineering techniques. However, the best achievable sensitivity still suffers from the intrinsically limited contrast of fluorescence-based Optically Detected Magnetic Resonance (ODMR) measurements. We are pursuing a magnetometry modality based on infrared absorption of the 1042 nm singlet transition of NV centers. This method allows for higher ODMR contrast and detection power, which in turn promises substantial improvements in sensitivity. Combined with other techniques for improving the sensitivity, like magnetic field concentrators, the absorption-based measurements offer a path for realizing femtotesla-level sensitivity.