基于图形化石墨烯的可调谐宽光谱太赫兹吸收器的研究

Tunable Broad-Spectral Terahertz Absorber Based on Graphic Graphene

设计了一种基于图形化石墨烯的太赫兹吸收器,呈现出可调谐超宽频的吸收特性。其顶部为超薄石墨烯层,中间为电介质层,底部为金层。通过改变中间介质层的厚度和顶层石墨烯的费米能级,对太赫兹吸收器进行设计与仿真,而石墨烯的费米能级可以通过改变栅极电压来调控。结果表明,该吸收器在低频部分呈现超宽频吸收,当吸收器的介质层厚度为30μm时,吸收特性达到最优,并且通过改变石墨烯的费米能级,能够动态调控吸收器的吸收特性,使得吸收峰值点和带宽发生动态变化,吸收峰值点在431 GHz区间内移动,实现了吸收器的可调谐功能。当石墨烯的费米能级为0.4 eV时,吸收率超过90%的频带宽度为1.8744 THz,吸收器峰值吸收率为99.3357%,达到了完美吸收。

In this study,a terahertz absorber based on graphic graphene,which exhibited tunable ultra-wideband absorption characteristics,was designed.The top,middle,and bottom of the absorber comprised ultra-thin graphene,dielectric,and gold layers,respectively.The absorber was designed and simulated by changing the thickness of the middle layer and the Fermi energy level of the top layer;the Fermi level of graphene could be controlled by changing the gate voltage.The results show that the absorber exhibits ultra-wide frequency absorption in the low-frequency region,and the absorption characteristics are optimized when the thickness of the middle layer is30μm;the opening and closing of the absorber can be controlled by changing the Fermi energy level of graphene,while the frequency position and bandwidth of the absorption peak are adjusted to make the absorption peak move close to 431 GHz,thus realizing a tunable function of the absorber.When the Fermi energy level of graphene is0.4 eV,the bandwidth with an absorption rate of more than 90%is 1.8744 THz and the peak absorption rate is99.3357%.The absorber achieves perfect absorption.