Measurement Sensitivity of the Optically Detected Magnetic Resonance for a Single NV– Center in Diamond

The spectra of the optically detected magnetic resonance for single NV^– centers have been experimentally studied in two solid-state samples in the range of hyperfine interactions between the electron spin and the nitrogen nucleus spin in the same NV^– center. This study has been aimed at reaching a maximal microwave frequency resolution in the experimental setup used. For measurements, two low-nitrogen (no higher than 50 ppb) diamond single-crystal samples have been grown. Measured time \(T_{2}^{*}\) of the spin decoherence in NV^– centers was about 2 μs in one sample and 20 μs in the other. For both samples, the spectrum of the optically detected magnetic resonance for the hyperfine splitting of a single NV^– center and ¹⁴N atom has been taken and investigated. The resolution in these samples has been estimated at a level of 3.5 and 0.18 MHz, respectively. It has been noted that the resolution of the spectrum improves with increasing time \(T_{2}^{*}\) of the spin decoherence of the single NV^– center.