Chowdhury Dibakar Roy, Su Xiaofang, Zeng Yong, Chen Xiaoshuang, Taylor Antoinette J, Azad Abul
Opt Express. 2014 Aug 11;22(16):19401-10. doi: 10.1364/OE.22.019401.
Plasmonic structures with high symmetry, such as double-identical gap split ring resonators, possess dark eigenmodes. These dark eigenmodes are dominated by magnetic dipole and/or higher-order multi-poles such as electric quadrapoles. Consequently these dark modes interact very weakly with the surrounding environment, and can have very high quality factors (Q). In this work, we have studied, experimentally as well as theoretically, these dark eigenmodes in terahertz metamaterials. Theoretical investigations with the help of classical perturbation theory clearly indicate the existence of these dark modes in symmetric plasmonic metamaterials. However, these dark modes can be excited experimentally by breaking the symmetry within the constituting metamaterial resonators cell, resulting in high quality factor resonance mode. The symmetry broken metamaterials with such high quality factor can pave the way in realizing high sensitivity sensors, in addition to other applications.
具有高对称性的等离子体结构，如双相同间隙分裂环谐振器，拥有暗本征模。这些暗本征模由磁偶极子和/或高阶多极子（如电四极子）主导。因此，这些暗模与周围环境的相互作用非常微弱，并且可以具有非常高的品质因数（Q）。在这项工作中，我们通过实验和理论研究了太赫兹超材料中的这些暗本征模。借助经典微扰理论的理论研究清楚地表明了对称等离子体超材料中这些暗模的存在。然而，这些暗模可以通过破坏构成超材料谐振器单元内的对称性在实验中被激发，从而产生高品质因数的共振模式。具有如此高品质因数的对称性破缺超材料除了其他应用外，还可以为实现高灵敏度传感器铺平道路。
