Mapping plasmonic near-field profiles and interferences by surface-enhanced Raman scattering.
Mapping plasmonic near-field profiles and interferences by surface-enhanced Raman scattering.
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通过表面增强拉曼散射绘制等离子体近场分布和干扰
DOI：
10.1038/srep03064
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发表时间：
2013-10-29
影响因子：
4.6
通讯作者：
Yuan X
中科院分区：
文献类型：
--
作者：
Du L;Lei DY;Yuan G;Fang H;Zhang X;Wang Q;Tang D;Min C;Maier SA;Yuan X
绘制表面等离子体激元的近场轮廓和动力学对于理解其基本光学特性和设计小型光子器件至关重要。这需要亚波长尺度的空间分辨率，因为有效极化子波长比自由空间激发波长短。在这里，通过将全内反射激发与表面增强拉曼散射成像相结合，我们通过垂直间隙模式的光谱选择性和偏振分辨激发，在亚波长尺度上绘制了金属纳米粒子-薄膜系统中表面等离子体场的主要垂直分量的空间分布。结处的横向场延伸由间隙模式体积决定，足够小，足以以高再现性区分由聚焦径向偏振光束产生的~0.355λ0 的光斑尺寸。相同的激发和成像方案还用于追踪近场纳米聚焦和由各种等离激元透镜产生的表面等离激元极化激元的干扰。
Mapping near-field profiles and dynamics of surface plasmon polaritons is crucial for understanding their fundamental optical properties and designing miniaturized photonic devices. This requires a spatial resolution on the sub-wavelength scale because the effective polariton wavelength is shorter than free-space excitation wavelengths. Here by combining total internal reflection excitation with surface-enhanced Raman scattering imaging, we mapped at the sub-wavelength scale the spatial distribution of the dominant perpendicular component of surface plasmon fields in a metal nanoparticle-film system through spectrally selective and polarization-resolved excitation of the vertical gap mode. The lateral field-extension at the junction, which is determined by the gap-mode volume, is small enough to distinguish a spot size ~0.355λ0generated by a focused radially polarized beam with high reproducibility. The same excitation and imaging schemes are also used to trace near-field nano-focusing and interferences of surface plasmon polaritons created by a variety of plasmon lenses.