Direct imaging of the near field and dynamics of surface plasmon resonance on gold nanostructures using photoemission electron microscopy
Direct imaging of the near field and dynamics of surface plasmon resonance on gold nanostructures using photoemission electron microscopy
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DOI：
10.1038/lsa.2013.74
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发表时间：
2013-12-01
影响因子：
19.4
通讯作者：
Misawa, Hiroaki
中科院分区：
文献类型：
--
作者：
Sun, Quan;Ueno, Kosei;Misawa, Hiroaki
局部表面等离子体共振（LSPR）可以由金属纳米颗粒和工程纳米结构支持。对LSPR的空间分辨近场特性和动力学的理解是重要的，但仍然具有实验挑战性。我们报告的实验研究，实现这一目标，使用光电子发射电子显微镜（PEEM）与高空间分辨率的子10 nm。各种工程金纳米结构阵列（如杆，纳米盘状颗粒和二聚体）的研究通过PEEM使用近红外（NIR）飞秒激光脉冲作为激发源。当LSPR波长与飞秒脉冲的光谱重叠时，LSPR被有效激发并促进多光子光发射，这与近场金属纳米颗粒的局部强度相关。因此，局部场分布的LSPR不同的Au纳米结构可以直接探索和讨论使用PEEM图像。此外，还结合干涉时间分辨泵浦-探测技术和脉冲电子显微镜对LSPR的动力学进行了研究。可以获得关于LSPR场的振荡和退相的详细信息。结果确定PEEM作为一个强大的工具，用于访问近场映射和等离子体纳米结构的动态特性。
Localized surface plasmon resonance (LSPR) can be supported by metallic nanoparticles and engineered nanostructures. An understanding of the spatially resolved near-field properties and dynamics of LSPR is important, but remains experimentally challenging. We report experimental studies toward this aim using photoemission electron microscopy (PEEM) with high spatial resolution of sub-10 nm. Various engineered gold nanostructure arrays (such as rods, nanodisk-like particles and dimers) are investigated via PEEM using near-infrared (NIR) femtosecond laser pulses as the excitation source. When the LSPR wavelengths overlap the spectrum of the femtosecond pulses, the LSPR is efficiently excited and promotes multiphoton photoemission, which is correlated with the local intensity of the metallic nanoparticles in the near field. Thus, the local field distribution of the LSPR on different Au nanostructures can be directly explored and discussed using the PEEM images. In addition, the dynamics of the LSPR is studied by combining interferometric time-resolved pump-probe technique and PEEM. Detailed information on the oscillation and dephasing of the LSPR field can be obtained. The results identify PEEM as a powerful tool for accessing the near-field mapping and dynamic properties of plasmonic nanostructures.