Double Fano Resonances in S-Shaped Plasmonic Metasurfaces in Terahertz Region

Frontiers in Physics

Lingling Chen¹  Zhi Hong¹  Weihang Xu¹  Jianjun Liu¹  Chuanshuai Sui¹  Fangming Zhu² 

[1] Centre for THz Research, China Jiliang University, Hangzhou, China;School of Information Science and Engineering, Hangzhou Normal University, Hangzhou, China;

关键词: Fano resonance;    metasurface;    plasmonic;    trapped mode;    terahertz;   

DOI  :  10.3389/fphy.2020.00256

来源: DOAJ

【 摘 要 】

We numerically and experimentally demonstrated double Fano resonances in a simple S-shaped plasmonic metasurface in the terahertz frequency range. Apart from the electric-LC resonance and electric dipole (ED) resonance, two trapped modes are excited in two different types of asymmetric S-shaped structures in the frequency range 0.2–1.4 THz, which are mainly attributed to a magnetic dipole (MD) and an electric quadrupole (EQ). Thereafter, double Fano resonances [one Fano and one electromagnetically induced transparency (EIT) resonance] are achieved via the coupling of the two dark trapped modes and a broad bright ED at normal incidence of the metasurfaces. Furthermore, under oblique incidence, strong Fano responses can be observed; they are considerably enhanced in asymmetric structures, and even in a symmetric structure. The proposed S-shaped plasmonic metasurfaces are easy to fabricate and have potential applications in multi-wavelength optical switches, filters, and sensors.

【 授权许可】

Unknown