Spectral hole burning and Raman heterodyne signals associated with an avoided crossing in the NV centre in diamond

The nitrogen-vacancy centre in diamond exhibits an avoided crossing of ground state electron spin levels in a magnetic field of similar to 1028 G applied along the [1 1 1] direction. In this paper, the magnetic field dependence of Raman heterodyne signals and the optical transmission at 638 nm in the vicinity of the avoided crossing are reported. It is discussed that the optically induced spin polarization of ground state populations produces anomalous fine structure hole-burning behaviour. (C) 2000 Elsevier Science B.V. All rights reserved.