基于石墨烯超材料的三频段可调谐完美吸收器  

Triple-band tunable terahertz perfect absorber based on graphene metamaterial

作　　者：李辉 余江[1] 陈哲 LI Hui;YU Jiang;CHEN Zhe(School of Information Science and Engineering,Yunnan University,Kunming 650500,China)

机构地区：[1]云南大学信息学院,昆明650500

出　　处：《电波科学学报》2021年第2期277-284,共8页Chinese Journal of Radio Science

基　　金：国家自然科学基金(61162004)。

摘　　要：为进一步降低太赫兹频率下高性能调控器件的结构复杂度,提出一种三频段可调谐超材料完美吸收器.该吸收器由图案化的石墨烯层和经Si介质层隔开的Au接地平面组成,利用太赫兹下的石墨烯表面等离子体共振以及图案化石墨烯与电场耦合提供的电偶极子共振形成多个吸收峰.数值仿真结果表明,在0.489 THz、1.492 THz和2.437 THz处实现了对入射波的共振吸收,各峰值处的幅值均大于99.9%.由于吸收峰处的幅值可以通过外部施加的偏置电压改变石墨烯的费米能级进行控制,因而所提出的吸收器结构的工作状态可在反射器和吸收器之间灵活切换.同时,通过对吸收器单元结构的对称设计实现了对极化角度的不敏感特性,且在宽入射角范围内仍能保持良好的吸收性能.因此,所设计的基于石墨烯的太赫兹超材料功能器件在调制和传感方面具有巨大的潜力.To further reduce the structural complexity of high-performance modulation devices in the terahertz region,we propose and demonstrate a triple-band tunable metamaterial perfect absorber,which consists of a patterned graphene and Au ground plane spaced by Si dielectric layer.The graphene surface plasmon resonance at the terahertz region is used to couple the patterned graphene with the electric field and provide electric dipole resonance to form multiple absorption peaks.Numerical results indicate that the amplitude of the absorption peaks is large than 99.9%at0.489 THz,1.492 THz,and 2.437 THz,respectively.In addition,due to the amplitude of the absorption peaks that can be controlled by the Fermi level via externally applied bias voltage,it means that we are able to switch the structure between reflector and absorber at their corresponding absorption bands.However,the symmetric unit cell structure of the proposed absorber is the inherent reason for the excellent polarization-insensitive,and the broadband absorption of the absorber maintains excellent absorption performance over a wide range of incident angles.Therefore,the designed graphene-based terahertz metamaterial function device has great potential in modulation and sensing.

关 键 词：超材料 吸收器 石墨烯 三频段 可调谐 极化不敏感 

分 类 号：TB34[一般工业技术—材料科学与工程]