A nitrogen-vacancy (NV) center is a defect in the crystal structure of diamond, where a nitrogen atom replaces a carbon atom in the diamond lattice and a neighboring site in the lattice is vacant. This and other fluorescent defects in diamond, known as color centers, have attracted researchers' attention owing to their quantum properties, such as single-photon emission at room temperature and with long coherence time. Their many applications include quantum information encoding and processing, and cell marking in biological studies.
