Graphene based tunable metamaterial absorber and polarization modulation in terahertz frequency
Graphene based tunable metamaterial absorber and polarization modulation in terahertz frequency
复制标题
基于石墨烯的可调谐超材料吸收体和太赫兹频率偏振调制
DOI：
10.1364/oe.22.022743
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发表时间：
2014-09-22
期刊：
影响因子：
3.8
通讯作者：
Jiang, Tian
中科院分区：
文献类型：
--
作者：
Zhang, Yin;Feng, Yijun;Jiang, Tian
石墨烯的薄层电导率可调，可用于设计可调太赫兹器件。本文将具有十字形金属谐振器单胞的超材料与双层石墨烯丝相结合，实现了具有太赫兹频率光谱调谐的偏振无关吸收体，并将其联合收割机。通过控制石墨烯的费米能，可以方便地实现对石墨烯双层的偏压控制，从而获得了峰值频率调谐范围为15%、峰值吸收几乎完美的吸收性能。提出的吸收器的机制已被探索的传输线模型和调谐的栅极电压偏置下的石墨烯线的有效电感的变化来解释。此外，我们还提出了一种利用类似的偏振相关吸收体对太赫兹波进行偏振调制的方案。通过所提出的偏振调制器，能够在工作频率下以连续可调的主轴方位角从0度到90度的线偏振电控制反射波。这些设计方法使我们能够更灵活地控制太赫兹波的吸收光谱和偏振态。2014美国光学学会Optical Society of America
Graphene can be utilized in designing tunable terahertz devices due to its tunability of sheet conductivity. In this paper, we combine the metamaterial having unit cell of cross-shaped metallic resonator with the double layer graphene wires to realize polarization independent absorber with spectral tuning at terahertz frequency. The absorption performance with a peak frequency tuning range of 15% and almost perfect peak absorption has been demonstrated by controlling the Fermi energy of the graphene that can be conveniently achieved by adjusting the bias voltage on the graphene double layers. The mechanism of the proposed absorber has been explored by a transmission line model and the tuning is explained by the changing of the effective inductance of the graphene wires under gate voltage biasing. Further more, we also propose a polarization modulation scheme of terahertz wave by applying similar polarization dependent absorbers. Through the proposed polarization modulator, it is able to electrically control the reflected wave with a linear polarization of continuously tunable azimuth angle of the major axis from 0 degrees to 90 degrees at the working frequency. These design approaches enable us to electrically control the absorption spectrum and the polarization state of terahertz waves more flexibly. (C)2014 Optical Society of America