• 文献标题:   Multilayer graphene-based metasurfaces: robust design method for extremely broadband, wide-angle, and polarization-insensitive terahertz absorbers
  • 文献类型:   Article
  • 作  者:   RAHMANZADEH M, RAJABALIPANAH H, ABDOLALI A
  • 作者关键词:  
  • 出版物名称:   APPLIED OPTICS
  • ISSN:   1559-128X EI 2155-3165
  • 通讯作者地址:   Iran Univ Sci Technol
  • 被引频次:   25
  • DOI:   10.1364/AO.57.000959
  • 出版年:   2018

▎ 摘  要

In this study, by using an equivalent circuit method, a polarization-insensitive terahertz (THz) absorber based on multilayer graphene-based metasurfaces (MGBMs) is systematically designed, providing an extremely broad absorption bandwidth (BW). The proposed absorber is a compact, three-layer structure, comprising square-, cross-, and circular-shaped graphene metasurfaces embedded between three separator dielectrics. The equivalent-conductivity method serves as a parameter retrieval technique to characterize the graphene metasurfaces as the components of the proposed circuit model. Good agreement is observed between the full-wave simulations and the equivalent-circuit predictions. The optimum MGBM absorber exhibits >90% absorbance in an extremely broad frequency band of 0.55-3.12 THz (BW = 140%). The results indicate a significant BW enhancement compared with both the previous metal-and graphene-based THz absorbers, highlighting the capability of the designed MGBM absorber. To clarify the physical mechanism of absorption, the surface current and the electric-field distributions, as well as the power loss density of each graphene metasurface, are monitored and discussed. The MGBM functionality is evaluated under a wide range of incident wave angles to prove that the proposed absorber is omnidirectional and polarization-insensitive. These superior performances guarantee the applicability of the MGBM structure as an ultra-broadband absorber for various THz applications. (C) 2018 Optical Society of America