Gao Fan, Yuan Peicheng, Gao Shaojun, Deng Juan, Sun Zhiyu, Jin Guoli, Zeng Guanglu, Yan Bo
Collaborative Innovation Center for Bio-Med Physics Information Technology of ZJUT, Zhejiang University of Technology, Hangzhou 310023, China.
Department of Physics, Zhejiang University of Technology, Hangzhou 310023, China.
Nanomaterials (Basel). 2021 Aug 10;11(8):2032. doi: 10.3390/nano11082032.
Electromagnetically induced transparency (EIT) based on dielectric metamaterials has attracted attentions in recent years because of its functional manipulation of electromagnetic waves and high refractive index sensitivity, such as high transmission, sharp phase change, and large group delay, etc. In this paper, an active controlled EIT effect based on a graphene-dielectric hybrid metamaterial is proposed in the near infrared region. By changing the Fermi level of the top-covered graphene, a dynamic EIT effect with a high quality factor (Q-factor) is realized, which exhibits a tunable, slow, light performance with a maximum group index of 2500. Another intriguing characteristic of the EIT effect is its high refractive index sensitivity. In the graphene-covered metamaterial, the refractive index sensitivity is simulated as high as 411 nm/RIU and the figure-of-merit (FOM) is up to 159, which outperforms the metastructure without graphene. Therefore, the proposed graphene-covered dielectric metamaterial presents an active EIT effect in the near infrared region, which highlights its great application potential in deep optical switching, tunable slow light devices, and sensitive refractive index sensors, etc.
近年来,基于介质超材料的电磁诱导透明(EIT)因其对电磁波的功能操控以及高折射率灵敏度,如高透射率、急剧的相位变化和大群延迟等,而备受关注。本文提出了一种基于石墨烯 - 介质混合超材料的有源可控EIT效应,该效应发生在近红外区域。通过改变顶部覆盖的石墨烯的费米能级,实现了具有高品质因数(Q因子)的动态EIT效应,其展现出可调谐、慢光特性,最大群折射率可达2500。EIT效应的另一个有趣特性是其高折射率灵敏度。在覆盖石墨烯的超材料中,模拟得到的折射率灵敏度高达411 nm/RIU,品质因数(FOM)高达159,优于无石墨烯的超结构。因此,所提出的覆盖石墨烯的介质超材料在近红外区域呈现出有源EIT效应,这突出了其在深度光开关、可调谐慢光器件和灵敏折射率传感器等方面的巨大应用潜力。