Extending the field of quantum metrology i.e., magnetometry, electrometry, and thermometry to the atomic scale requires robust sensors with high sensitivity and spatial resolution. Optically addressable spins in diamond are excellent candidates as they often come with outstanding stability and narrow transitions, facilitating high sensitivity and nanometer resolution.
The Nitrogen-Vacancy (NV) center has already proven its applicability to quantum sensing of magnetic and electric fields as well as temperature at nanometer scale. Unfortunately, strong magnetic fields lead to a mixing of the NV sub-levels which prevents effective spin initialization (spin pumping) for field-orientations not aligned with the NV symmetry axis. As a result, transitions within the NV center can no longer be observed in optically detected magnetic resonance measurement, hindering the sensing of strong magnetic fields for arbitrary orientations.
The researchers have presented an extensive optically detected magnetic resonance study on individual TR12 centers in diamond which show much larger acceptance angle in high magnetic field and can sense magnetic fields up to several tens or even hundreds of mT for arbitrary orientation allowing for full vector magnetometry under ambient conditions.
They showed that the TR12 radiative defect in diamond, exhibits strong Optically Detected Magnetic Resonance (ODMR) signal under optical saturation. They also demonstrated that the spin system responsible for the magnetic resonance is an excited triplet state that can be coherently controlled at room temperature on a single defect level. The high optically detected magnetic resonance contrast, which is maintained even for strong off-axis magnetic fields, suggests that TR12 centers can be used for vector magnetometry even at high field.
The paper has been published in npj Quantum Information.
