Zhang Siwen, Liu Haitao, Sun Xiaodong
J Opt Soc Am A Opt Image Sci Vis. 2014 Jun 1;31(6):1194-9. doi: 10.1364/JOSAA.31.001194.
We provide an elaborate investigation on the role of a hybrid wave (HW) in electromagnetic enhancement by a groove doublet in metallic substrate. A simple HW model is built to explore the detailed effect of HW on electromagnetic enhancement. The effective range of electromagnetic enhancement is obtained within 0.1λ away from a metal surface. The excitation of HW by a single groove has a gentle growth (from 0.03 to 0.26) as the groove gets wide, which implies that the emerging field of HW launched by a single groove is quite weak for narrow ones. HW, being like an "energy porter," takes away partial energy from the Fabry-Perot resonance, which will be further coupled into the fundamental mode in the other groove after traveling along the metal surface. Our analysis reveals a compensation of electromagnetic enhancement for wide grooves attributed to the appearance of HW. The dependence of HW and electromagnetic enhancement on the noble metal type is also discussed.
我们对混合波（HW）在金属基底中槽型双峰结构电磁增强作用方面进行了详尽研究。构建了一个简单的HW模型来探究HW对电磁增强的具体影响。在距离金属表面0.1λ范围内获得了电磁增强的有效范围。随着槽变宽，单个槽对HW的激发呈平缓增长（从0.03至0.26），这意味着对于窄槽而言，单个槽所激发的HW的新兴场相当微弱。HW就像一个“能量搬运工”，从法布里-珀罗共振中带走部分能量，这部分能量在沿金属表面传播后会进一步耦合到另一个槽中的基模。我们的分析揭示了由于HW的出现，宽槽的电磁增强存在一种补偿现象。同时还讨论了HW和电磁增强对贵金属类型的依赖性。
