Mediated coupling of surface plasmon polaritons by a moving electron beam.
Mediated coupling of surface plasmon polaritons by a moving electron beam.
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DOI：
10.1364/oe.25.025919
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发表时间：
2017-10
期刊：
影响因子：
3.8
通讯作者：
S. Gong;Min Hu;R. Zhong;T. Zhao;Chao Zhang-;Shenggang Liu
中科院分区：
文献类型：
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作者：
S. Gong;Min Hu;R. Zhong;T. Zhao;Chao Zhang-;Shenggang Liu
本文研究了平行运动电子束对表面等离子体激元的介导耦合。理论分析表明，电子束在金属薄膜上方的光栅上激发的表面等离子体激元（SSP）在介导耦合中起着激发源的作用。数值计算和粒子模拟结果表明，与平行运动电子束直接耦合的表面等离子体相比，表面等离子体耦合表面等离子体具有明显的优势。当电子束的电荷密度为100 nC/cm时，双耦合表面等离子体的光密度可达106/cm ~ 2，比直接耦合表面等离子体的光密度高两个数量级。当束流能量在10 ~ 30 keV范围内时，双耦合SPP的调谐带宽可达9%，而直接耦合SPP几乎不能调谐。光耦合SPP的寿命也更长，可达数百飞秒。因此，这种介导的偶联对SPP的应用具有重要意义。
The mediated coupling of surface plasmon polaritons (SPPs) by a parallel moving electron beam is demonstrated in this paper. The theoretical analysis shows that the electron beam excited spoof surface plasmon polaritons (SSPs) on the grating placed above the metal films play the role as the excitation source in the mediated coupling. The numerical calculations and particle-in-cell simulations demonstrate the significant advantages of the SSPs mediately coupled SPPs in contrast with that coupled by the parallel moving electron beam directly. The photo density of the mediately coupled SPPs reaches up to 106 per cm2 for the electron beam with the charge density 100 nC/cm, which is two orders of magnitude larger than that of the directly coupled SPPs. The tuning band of the mediately coupled SPPs reaches up to 9% for the beam energy ranging from 10 keV to 30 keV, while it almost cannot be tuned for the direct coupling. The lifetime of the mediately coupled SPPs, which reaches up to hundreds of femtoseconds, is also much longer. Accordingly, the mediated coupling may bring great significances for the applications of SPPs.