The observation of single molecule events using surface-enhanced Raman scattering (SERS) is a well-established phenomenon. These events are characterized by strong fluctuations in SERS intensities. High-speed SERS intensity fluctuations (in the microsecond time scale) have been reported for experiments involving single metallic particles. In this work, the high-speed SERS behavior of six different types of nanostructured metal systems (Ag nanoshells, Ag nanostars, Ag aggregated spheres, Au aggregated spheres, particle-on-mirror, and Ag deposited on microspheres) was investigated. All systems demonstrated high-speed SERS intensity fluctuations. Statistical analysis of the duration of the SERS fluctuations yielded tailed distributions with average event durations around 100 μs. Although the characteristics of the fluctuations seem to be random, the results suggest interesting differences between the system that might be associated with the strength distribution and density of the localized SERS hotspots. For instance, systems with more localized fields, such as nanostars, present faster fluctuation bursts compared to metallic aggregates that support spread-out fields. The results presented here appear to confirm that high-speed SERS intensity fluctuations are a fundamental characteristic of the SERS effect.

中文翻译：

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来自各种纳米结构的表面增强拉曼散射强度的高速波动

使用表面增强拉曼散射 (SERS) 观察单分子事件是一种公认​​的现象。这些事件的特点是 SERS 强度的剧烈波动。已经报道了涉及单个金属颗粒的实验的高速 SERS 强度波动（以微秒为单位）。在这项工作中，研究了六种不同类型的纳米结构金属系统（银纳米壳、银纳米星、银聚合球、金聚合球、镜上粒子和沉积在微球上的银）的高速 SERS 行为。所有系统都表现出高速 SERS 强度波动。SERS 波动持续时间的统计分析产生了平均事件持续时间约为 100 μs 的拖尾分布。虽然波动的特征看似随机，结果表明系统之间的有趣差异可能与局部 SERS 热点的强度分布和密度有关。例如，与支持扩展场的金属聚集体相比，具有更多局部场的系统（如纳米星）呈现出更快的波动爆发。这里呈现的结果似乎证实了高速 SERS 强度波动是 SERS 效应的基本特征。