Manjappa Manukumara, Turaga Shuvan Prashant, Srivastava Yogesh Kumar, Bettiol Andrew Anthony, Singh Ranjan
Opt Lett. 2017 Jun 1;42(11):2106-2109. doi: 10.1364/OL.42.002106.
Dark mode in metamaterials has become a vital component in determining the merit of the Fano type of interference in the system. Its strength dictates the enhancement and suppression in the amplitude and Q-factors of resulting resonance features. In this work, we experimentally probe the effect of strong near-field coupling on the strength of the dark mode in a concentrically aligned bright resonator and a dark split ring resonator (SRR) system exhibiting the classical analog of the electromagnetically induced transparency effect. An enhanced strong magnetic field between the bright-dark resonators destructively interferes with the inherent magnetic field of the dark mode to completely annihilate its effect in the coupled system. Moreover, the observed annihilation effect in the dark mode has a direct consequence on the disappearance of the SRR effect in the proposed system, wherein under the strong magnetic interactions, the LC resonance feature of the split ring resonator becomes invisible to the incident terahertz wave.
超材料中的暗模式已成为决定系统中Fano型干涉优劣的关键因素。其强度决定了所产生共振特征的幅度和品质因数的增强与抑制。在这项工作中，我们通过实验探究了强近场耦合对同心排列的亮谐振器和暗裂环谐振器（SRR）系统中暗模式强度的影响，该系统展现出电磁诱导透明效应的经典类似物。亮-暗谐振器之间增强的强磁场与暗模式的固有磁场相消干涉，从而在耦合系统中完全消除其影响。此外，在暗模式中观察到的消光效应直接导致了所提出系统中SRR效应的消失，即在强磁相互作用下，裂环谐振器的LC共振特征对入射太赫兹波变得不可见。
