Stimulated emission assisted time-gated detection of a solid-state spin

The nitrogen vacancy (NV) center in diamond is studied widely for magnetic field and temperature sensing at the nanoscale. Usually, the fluorescence is recorded to estimate the spin state of the NV center. Here we applied a time-gating technique to improve the contrast of the spin-dependent fluorescence. A NIR pulsed laser pumped the stimulated emission of the NV center and depleted the spontaneous emission that was excited by a green laser. We changed the relative delay between the NIR laser and the green laser. Then the spontaneous emission of the NV center in varied time windows was extracted by comparing the fluorescence intensities with and without the NIR laser. The results showed that the spin-dependent fluorescence contrast could be improved by approximately 1.8 times by applying the time gating. The background of the environment was eliminated due to temporal filtering. This work demonstrates that the stimulated emission assisted time-gating technique can be used to improve the performance of an NV center sensor in a noisy environment.