Gao Fei, Gao Zhen, Shi Xihang, Yang Zhaoju, Lin Xiao, Zhang Baile
Opt Express. 2015 Mar 9;23(5):6896-902. doi: 10.1364/OE.23.006896.
We propose and experimentally demonstrate an approach to efficiently tune the dispersion of a designer-plasmonic resonator, or a plasmonic 'meta-atom', by incorporating an extra ground plane underneath. We demonstrate that this ground plane is able to enhance resonances, and the enhancing effect can render those higher-order azimuthal modes, being absent in previously reported designer-plasmonic resonators, experimentally observable. After incorporating the ground plane, all resonance modes are red shifted with their Q factors enhanced. By increasing the separation from the planar resonator to the underneath ground plane, all enhanced modes are blue shifted with Q factors decreased slightly, whose trend is opposite to increasing the thickness of a dielectric substrate of a common meta-atom without a ground. These results may find potential applications in tunable designer-plasmonic sensors and plasmonic metamaterial designs.
我们提出并通过实验证明了一种方法，即通过在下方并入一个额外的接地平面来有效调节定制等离子体谐振器或等离子体“元原子”的色散。我们证明，该接地平面能够增强共振，并且这种增强效应能使先前报道的定制等离子体谐振器中不存在的高阶方位模式在实验中可被观测到。并入接地平面后，所有共振模式都发生红移，其品质因数得到提高。通过增加平面谐振器与下方接地平面之间的间距，所有增强模式都发生蓝移，品质因数略有下降，这一趋势与增加无接地普通元原子的介电基板厚度时相反。这些结果可能在可调谐定制等离子体传感器和等离子体超材料设计中找到潜在应用。
