Reddy Innem V A K, Jornet Josep M, Baev Alexander, Prasad Paras N
Opt Lett. 2020 Oct 15;45(20):5744-5747. doi: 10.1364/OL.402647.
Epsilon-near-zero (ENZ) materials display unique properties, and among them, large local field enhancement at ENZ frequency is of particular interest for many potential applications. In this Letter, we introduce the concept that a combination of epsilon-near-zero and surface plasmon polariton modes can be excited over an interface between a dielectric and a single ENZ layer in a specific frequency region, which can lead to extreme enhancement of local electric field. We demonstrate it with a systematic numerical simulation using finite element analysis and consider two configurations (Kretschmann configuration and a grating configuration), where an indium tin oxide (ITO) layer is sandwiched between two dielectric slabs. We confirm the formation of a hybrid mode at the ITO-dielectric interface at the wavelength of ENZ, as the ITO layer thickness reduces. The hybrid mode provides both high confinement and long propagation distance, which makes it more attractive for many applications than just a pure ENZ mode.
近零介电常数（ENZ）材料展现出独特的性质，其中，在ENZ频率下的大局部场增强对于许多潜在应用尤为重要。在本信函中，我们提出了一个概念，即在特定频率区域内，介电体与单个ENZ层之间的界面上可以激发近零介电常数和表面等离激元极化激元模式的组合，这会导致局部电场的极大增强。我们使用有限元分析通过系统的数值模拟对其进行了论证，并考虑了两种配置（Kretschmann配置和光栅配置），其中氧化铟锡（ITO）层夹在两个介电平板之间。我们证实，随着ITO层厚度的减小，在ENZ波长处的ITO - 介电体界面会形成一种混合模式。这种混合模式兼具高限制和长传播距离的特性，这使得它比单纯的ENZ模式在许多应用中更具吸引力。
