  This article proposes a scheme for nitrogen-vacancy (NV) center magnetometry
that combines the advantages of lock-in detection and pulse-type scheme. The
optimal conditions, optimal sensitivity, and noise-suppression capability of
the proposed method are compared with those of the conventional methods from
both theoretical and simulation points of view. Through experimental
measurements, a four-time improvement in sensitivity and 60-times improvement
in minimum resolvable magnetic field (MRMF) was obtained. By using a confocal
experiment setup, proposed scheme achieves a sensitivity of 3 nT/Hz1/2 and a
MRMF of 100 pT.
