Optimization of solid atomic magnetometer with frequency modulation method on ensembles of nitrogen vacancy color centers in diamond

In this paper, we explored the optimal rate and amplitude parameters of microwave-modulated signal applied on ensembles of NV centers where the linear slope of the derivation of optically detected magnetic resonance reached the maximum both theoretically and experimentally. Further, we compared the linear slope of the derivation of the optically detected magnetic resonance and frequency response induced by rectangular modulation, which was 1.38 and approximately 10 times higher than that of sine-wave modulation. Besides, the noise levels when two-signal modulation was used were compared, which showed that the magnetic field sensitivity of the magnetometer with rectangular-wave modulation approached as low as 9.4 nT √Hz−1.