Opt Express. 2023 May 8;31(10):16645-16658. doi: 10.1364/OE.487142.
Considering the widespread applications of resonant phenomena in metasurfaces to bend, slow, concentrate, guide and manipulate lights, it is important to gain deep analytical insight into different types of resonances. Fano resonance and its special case electromagnetically induced transparency (EIT) which are realized in coupled resonators, have been the subject of many studies due to their high-quality factor and strong field confinement. In this paper, an efficient approach based on Floquet modal expansion is presented to accurately predict the electromagnetic response of two-dimensional/one-dimensional Fano resonant plasmonic metasurfaces. Unlike the previously reported methods, this method is valid over a wide frequency range for different types of coupled resonators and can be applied to practical structures where the array is placed on one or more dielectric layers. Given that the formulation is written in a comprehensive and flexible way, both metal-based and graphene-based plasmonic metasurfaces under normal/oblique incident waves are investigated, and it is demonstrated that this method can be posed as an accurate tool for the design of diverse practical tunable/untunable metasurfaces.
考虑到共振现象在超表面中广泛应用于弯曲、减慢、集中、引导和操纵光，深入了解不同类型的共振现象非常重要。由于具有高品质因数和强场限制，在耦合谐振器中实现的 Fano 共振及其特殊情况电磁感应透明（EIT）已经成为许多研究的主题。本文提出了一种基于 Floquet 模态展开的有效方法，可准确预测二维/一维 Fano 共振等离子体超表面的电磁响应。与之前报道的方法不同，该方法在不同类型的耦合谐振器的宽频率范围内有效，并且可应用于将阵列放置在一个或多个介电层上的实际结构。由于公式以全面灵活的方式编写，因此研究了正常/斜入射波下基于金属和基于石墨烯的等离子体超表面，并证明该方法可以作为设计各种可调谐/不可调谐超表面的精确工具。
