Resonant wedge-plasmon modes in single-crystalline gold nanoplatelets
Resonant wedge-plasmon modes in single-crystalline gold nanoplatelets
复制标题
单晶金纳米片中的共振楔形等离子体模式
DOI：
10.1103/physrevb.83.195433
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发表时间：
2011-05-24
影响因子：
3.7
通讯作者：
Mao, Jian
中科院分区：
文献类型：
--
作者：
Gu, Lin;Sigle, Wilfried;Mao, Jian
利用能量过滤透射电子显微镜在高空间分辨率下测量了不同形状和边缘长度的金纳米薄片的表面等离子体共振。我们发现沿血小板边缘能量损失概率的等距最大值。不同几何形状的等离子体色散非常相似，即几乎不依赖于试样的形状。通过时域有限差分计算验证了实验结果，发现沿血小板边缘传播的楔形等离子激元极化子的存在。在血小板角落，除了辐射损失外，楔形等离子激元的极化子被部分反射或传输到邻近的边缘。所有这些贡献的干涉导致了观测到的等离子体共振模式。这是深入了解棱柱形纳米片中等离子体特征模式的重要一步。
Using energy-filtered transmission electron microscopy we measured surface-plasmon resonances of gold nanoplatelets with different shapes and edge lengths at high spatial resolution. We find equidistant maxima of the energy-loss probability along the platelet edges. The plasmon dispersion of the different geometries is very similar, i.e., hardly dependent on specimen shape. The experimental results are verified by means of finite-difference time-domain calculations which reveal the presence of wedge-plasmon polaritons propagating along the platelet edges. At platelet corners, apart from radiative losses, wedge-plasmon polaritons are partially reflected or transmitted to neighboring edges. The interference of all these contributions leads to the observed plasmon resonance modes. This is an essential step towards a thorough understanding of plasmon eigenmodes in prismatic nanoplatelets.