The concentration estimation for ensemble of NV– color centers with spin coherent manipulation

The concentration and distribution of negatively charged nitrogen-vacancy color centers (NV − ) directly affect the sensitivity and resolution of quantum sensing. In this paper, a simple method is proposed to estimate the concentration of the ensemble of NV − centers with spin coherent manipulation. The stray fluorescence is eliminated by separating the fluorescence near the NV − zero-phonon line. By introducing a single NV − fluorescence quantitative model, the number of NV − centers in the diamond under test can be obtained. The average concentration of the ensemble of NV − centers in the sample can be obtained by combining the detection volume. Compared with the results measured by electron spin resonance, the concentration of NV − centers measured by our method can be verified, and the maximum error between the two methods is less than 4.3%. The results show that the method provides an effective reference for accurately characterizing the concentration distribution characteristics of the NV − ensemble.