Influence of Cross Sectional Geometry on Surface Plasmon Polariton Propagation in Gold Nanowires
Influence of Cross Sectional Geometry on Surface Plasmon Polariton Propagation in Gold Nanowires
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DOI：
10.1021/nn405183r
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发表时间：
2014-01-01
期刊：
影响因子：
17.1
通讯作者：
Link, Stephan
中科院分区：
文献类型：
--
作者：
Nauert, Scott;Paul, Aniruddha;Link, Stephan
利用漂白成像等离子体波传播和电磁场模拟研究了金纳米线中横截面几何形状对表面等离子体极化激元传播的影响。化学合成的纳米线具有五边形孪晶晶体结构，但最近的合成进展使得有可能放大这种五边形形状，以产生具有五角星形星星横截面和尖锐末端的纳米线。我们实验发现，与具有五边形横截面的光滑纳米线（标记为PNW）相比，具有五角形星星横截面的纳米线（称为SNW）在785 nm处具有较短的表面等离子体激元传播长度，但具有更高的有效耦合效率。电磁模拟表明，电场局部化在尖锐的脊的SNW，导致更高的吸收损耗，因此较短的传播长度相比，PNW。另一方面，散射损失被发现是相对不相关的横截面的几何形状，但强烈依赖于激发的等离子体激元模式。我们的研究结果提供了深入了解化学合成的金属纳米线的形状依赖的波导特性和模式依赖的损耗机制，管理表面等离子体极化激元传播。
We investigated the effects of cross sectional geometry on surface plasmon polariton propagation in gold nanowires (NWs) using bleach-imaged plasmon propagation and electromagnetic simulations. Chemically synthesized NWs have pentagonally twinned crystal structures, but recent advances in synthesis have made it possible to amplify this pentagonal shape to yield NWs with a five-pointed-star cross section and sharp end tips. We found experimentally that NWs with a five-pointed-star cross section, referred to as SNWs, had a shorter propagation length for surface plasmon polaritons at 785 nm, but a higher effective incoupling efficiency compared to smooth NWs with a pentagonal cross section, labeled as PNWs. Electromagnetic simulations revealed that the electric fields were localized at the sharp ridges of the SNWs, leading to higher absorptive losses and hence shorter propagation lengths compared to PNWs. On the other hand, scattering losses were found to be relatively uncorrelated with cross sectional geometry, but were strongly dependent on the plasmon mode excited. Our results provide insight into the shape-dependent waveguiding properties of chemically synthesized metal NWs and the mode-dependent loss mechanisms that govern surface plasmon polariton propagation.