基于单层石墨烯的偏振无关和入射角度不敏感的可切换宽带吸收器/反射器  

Polarization-Independent and Incident-Angle-Insensitive Switchable Broadband Absorber/Reflector Based on Single-Layer Graphene

作　　者：李辉 余江[1] 陈哲 Li Hui;Yu Jiang;Chen Zhe(School of Information,Yunnan University,Kunming,Yunnan 650500,China)

机构地区：[1]云南大学信息学院,云南昆明650500

出　　处：《中国激光》2020年第8期133-139,共7页Chinese Journal of Lasers

基　　金：国家自然科学基金(61162004)。

摘　　要：提出了一种新型的宽带可调谐超材料吸收器/反射器的设计方案,该结构由方形的单层石墨烯和被SiO2介质层隔开的金属接地平面组成。由于单元结构的对称性,在光波垂直入射时该吸收器具有极化不敏感特性。通过连续地调节石墨烯的费米能级,可以改变其表面电导率,使得该结构在整个宽吸收带上的工作状态可以在反射器和吸收器之间切换。数值仿真结果表明,该吸收器的吸收率在90%以上的吸收带宽达到了4.13THz,并且吸收器在65°的宽入射角范围内保持着良好的宽带吸收性能。所提吸收器可以广泛应用于高性能的太赫兹设备中,如有源伪装、成像、调制器和光电开关等。A novel tunable broadband metamaterial absorber/reflector is designed.Its structure consists of square single-layer graphene and a metal ground plane separated by a dielectric layer of SiO2.Due to the symmetry of the unit cell,the absorber is polarization insensitive when the light wave is incident vertically.By continuously adjusting the Fermi level of graphene,the surface conductivity of graphene can be tuned,and the working state of the proposed structure can be switched between the reflector and the absorber throughout the whole broad absorption band.The numerical simulation results show that the absorption bandwidth of the absorber reaches 4.13 THz at absorptivity larger than 90%,and the absorber maintains good broadband absorption performance within a wide incidence angle range of 65°.The proposed absorber can be widely used in high-performance terahertz devices,such as active camouflage,imaging,modulators and photoelectric switches.

关 键 词：材料 超材料 吸收 石墨烯 极化不敏感 光电开关 

分 类 号：TB34[一般工业技术—材料科学与工程]