Nitrogen-vacancy (NV) centers in diamond are reliable single-photon emitters, with applications in quantum technologies and metrology. Two charge states are known for NV centers, NV0 and NV-, with the latter being mostly studied due to its long electron spin coherence time. Therefore, control over the charge state of the NV centers is essential. However, an understanding of the dynamics between the different states still remains challenging. Here, conversion from NV- to NV0 due to electron-induced carrier generation is shown. Ultrafast pump-probe cathodoluminescence spectroscopy is presented for the first time, with electron pulses as pump and laser pulses as probe, to prepare and read out the NV states. The experimental data are explained with a model considering carrier dynamics (0.8 ns), NV0 spontaneous emission (20 ns), and NV0 → NV- back transfer (500 ms). The results provide new insights into the NV- → NV0 conversion dynamics and into the use of pump-probe cathodoluminescence as a nanoscale NV characterization tool.

中文翻译：

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用Pump-Probe阴极发光光谱法测量Diamond NV中心的电子诱导态转换。

钻石中的氮空位（NV）中心是可靠的单光子发射器，并在量子技术和计量学中得到应用。NV中心有两个电荷状态，即NV0和NV-，后者由于其长的电子自旋相干时间而被大量研究。因此，控制NV中心的充电状态至关重要。但是，对不同状态之间动态关系的理解仍然具有挑战性。在此，显示了由于电子诱导的载流子产生而从NV-转换为NV0的过程。首次提出超快泵浦探针阴极荧光光谱法，以电子脉冲作为泵浦，激光脉冲作为探针，以准备和读出NV态。用考虑载流子动力学（0.8 ns），NV0自发发射（20 ns），NV0→NV-向后传输（500 ms）。结果为NV-→NV0转化动力学以及泵浦探针阴极发光作为纳米级NV表征工具的使用提供了新的见解。