Nitrogen-vacancy center

The nitrogen-vacancy center (N-V center or NV center) is one of numerous photoluminescentpoint defects in diamond. It consists of a nearest-neighbor pair of a nitrogen atom, which substitutes for a carbon atom, and a lattice vacancy.

The most explored and useful properties of an NV center include its spin-dependent photoluminescence (which enables measurement of the electronic spin state using optically detected magnetic resonance), and its relatively long spin coherence at room temperature, lasting up to milliseconds. The NV center energy levels are modified by magnetic fields, electric fields, temperature, and strain, which allow it to serve as a sensor of a variety of physical phenomena. Its atomic size and spin properties can form the basis for useful quantum sensors.

NV centers enable nanoscale measurements of magnetic and electric fields, temperature, and mechanical strain with improved precision. Beyond sensing, NV centers have been investigated as room-temperature polarization sources for nuclear spins in diamond. Optically induced cross relaxation between NV centers and substitutional nitrogen defects (P1 centers) in the ground state has been identified as the dominant mechanism for bulk C hyperpolarization, enabling significant enhancement of nuclear magnetic resonance signals without requiring microwave excitation or cryogenic conditions. External perturbation sensitivity makes NV centers ideal for applications in biomedicine—such as single-molecule imaging and cellular process modeling. NV centers can also be initialized as qubits and enable the implementation of quantum algorithms and networks. It has also been explored for applications in quantum computing (e.g. for entanglement generation), quantum simulation, and spintronics.