基于石墨烯超材料的宽频带太赫兹吸收器

Broadband Terahertz Absorber Based on Graphene Metamaterial

为了拓展太赫兹吸收器的相对吸收带宽,设计了一种基于石墨烯超材料的超薄、宽频带、可调谐的太赫兹吸收器,其由图案化石墨烯层、电介质层和金属反射底板层叠构成。仿真结果表明:该吸收器在4.48 THz频率处的吸收率为99.98%,通过调节石墨烯的化学势可使该频点处的吸收率变化至25.08%;同时,该吸收器表现出对入射波极化不敏感的吸收特性,且在太赫兹波倾斜入射的情况下仍能保持一定的宽频带吸收特性。在此基础上设计了基于三层图案化石墨烯的太赫兹吸收器,其可进一步拓展吸收频带宽度,仿真结果表明该吸收器在1.90~5.49 THz频率之间的吸收率高于90%,相对吸收带宽为97%。

In order to expand the relative absorption bandwidth of terahertz absorber,an ultra-thin,wide-band,and tunable terahertz absorber based on graphene metamaterial is designed,which is composed of patterned graphene layer,dielectric layer,and metal reflection substrate.The simulation results show that the absorptivity of the absorber at 4.48 THz frequency is 99.98%,and the absorptivity at this frequency can be changed to 25.08%by adjusting the chemical potential of graphene.At the same time,the absorber shows the absorption characteristic of insensitive to the polarization of incident wave,and can still maintain a certain wide-band absorption characteristic when the terahertz wave is tilted.On this basis,a terahertz absorber based on three-layer patterned graphene is designed,which can further expand the absorption bandwidth.The simulation results show that the absorption rate of the absorber is higher than 90%,and the relative absorption bandwidth is 97%between 1.90 THz and 5.49 THz.