Importance of diffraction in determining the dispersion of designer surface plasmons
Importance of diffraction in determining the dispersion of designer surface plasmons
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DOI：
10.1103/physrevb.78.235426
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发表时间：
2008-12-01
影响因子：
3.7
通讯作者：
Sambles, J. R.
中科院分区：
文献类型：
--
作者：
Hendry, E.;Hibbins, A. P.;Sambles, J. R.
通过采用改进的模态匹配方法，我们获得了限制在真空和二维方孔阵列图案的完美导体之间界面处的表面电磁模式的频率与面内波矢量相关的明确解析表达式。我们完整的分析形式考虑了多阶波导模式和衍射倏逝波，因此克服了先前对这些表面波色散的描述所固有的先验假设。我们通过与最近使用棱镜耦合在微波频率记录的色散关系进行比较来验证我们得出的色散关系。最后，我们表明，衍射倏逝波在确定色散方面发挥着重要作用，因此与“设计”表面模式相关的电场比与真实金属表面上的表面等离子体相关的场更弱地限制在界面上。
By employing a modified modal matching approach, we obtain explicit analytical expressions relating frequency to in-plane wave vector for the surface electromagnetic mode confined at the interface between vacuum and a perfect conductor patterned with a two-dimensional square array of square holes. Our complete analytical formalism takes into account both multiple order waveguide modes and diffracted evanescent waves, hence overcoming the a priori assumptions intrinsic to previous descriptions of the dispersion of these surface waves. We validate our derived dispersion relation through comparison with that recently recorded at microwave frequencies using prism coupling. Finally, we show that diffracted evanescent waves play an important role in determining the dispersion, so that the electric field associated with "designer" surface modes is much more weakly confined to the interface than the field associated with surface plasmons on real metal surfaces.