Side resonances in diamond: influence of isotopic substitution of carbon
We discuss the structure of optically detected magnetic resonance (ODMR) spectra of diamond crystal. We propose the new approach to the calculation of hyperfine interaction in composed system, consisted of negatively charged nitrogen-vacancy (NV) center and nearby C<sup>13</sup> nuclear spin. Energy levels, rule selection and radiative transitions are obtained by new method. It is obtained the estimation of the carbon hyperfine splitting parameters in the diamond NV<sup>-</sup> center from side-resonance frequencies in the frame of this method. The base of this method is the using of entangled spin states.