Precise detection of surface plasmons is crucial for the research of nanophotonics and quantum optics. In this Letter, we used a single nitrogen vacancy center in diamond as a probe to detect the surface plasmon that was tuned by the thickness of a metallic film. The fluorescence intensity and lifetime of the nitrogen vacancy (NV) center were measured to obtain the information of local light–matter interaction. A nonlinear thickness dependent change of the surface plasmon was observed, with the maximum at the thickness of approximately 30 nm. With optimized thickness of silver film, the fluorescence intensity of a single NV center was enhanced 2.6 times, and the lifetime was reduced by a factor of 3, without affecting the coherence time of the NV spin state. The results proved that this system can quantitatively detect the light–matter interaction at nanoscale, and it provides an approach to enhance the fluorescence intensity of a quantum emitter.

中文翻译：

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通过氮中空位中心检测到的银膜厚度依赖的表面等离子体激元

表面等离激元的精确检测对于纳米光子学和量子光学的研究至关重要。在这封信中，我们使用金刚石中的单个氮空位中心作为探针来检测由金属膜的厚度调整的表面等离激元。测量氮空位（NV）中心的荧光强度和寿命，以获得局部光-物质相互作用的信息。观察到了表面等离子体激元的非线性厚度依赖性变化，在约30nm的厚度处具有最大值。通过优化银膜厚度，单个NV中心的荧光强度提高了2.6倍，并且寿命缩短了3倍，而不会影响NV自旋态的相干时间。