Infrared emission of the NV centre in diamond: Zeeman and uniaxial stress studies

An emission band in the infrared (IR) is shown to be associated with a transition within the negative nitrogen-vacancy centre in diamond. The band has a zero-phonon line at 1046 nm, and uniaxial stress and magnetic field measurements indicate that the emission is associated with a transition between (1)E and (1)A(1) singlet levels. Inter-system crossing to these singlets causes the spin polarization that makes the NV(-) centre attractive for quantum information processing, and the IR emission band provides a new avenue for using the centre in such applications.