Definition of the NV-center orientations relative to the diamond crystal plane

Abstract We investigate the electron spin resonance of an ensemble of Nitrogen-Vacancy color centers in a bulk diamond crystal obtained by CVD-method. The diamond crystal had 1 ppm concentration of nitrogen. The four possible orientations of the NV-center in the crystal lattice lead to different dependences of a magnitude and an orientation of the external static magnetic field. We used the field of 35 Gauss with the vector in the plane of the crystal. We could rotate it to a certain angle within almost 360 degrees around the normal vector to the plane of the crystal. The goal was to define the unknown orientations of the four axes of the NV-centers relatively to the crystal plane. Experimental results obtained at room temperature with a continuous microwave excitation and presented in this paper are in a good agreement with our simulations.