基于石墨烯的太赫兹波调控器件研究

The lack of modulation and control devices for terahertz (THz) wave is the key problem which is needed to be solved in the development of THz technology. The study of functional materials that can effectively interact with THz waves and the research on methods to design devices are effective ways to solve this problem. The two-dimensional material graphene has become an ideal material for terahertz functional devices for its unique carrier characteristics and excellent photoelectric properties. The project aims at improving the THz modulation depth of graphene. In this project, the electromagnetic response and optical pumping characteristics of graphene with different layers, different doping levels, graphene-metamaterials and the structure parameters of graphene metasurface are studied both theoretically and experimentally in the THz band. The theoretical model of the THz response will be established to disclose the physical mechanisms of THz modulation. It is expected to explore the basic laws that affect the THz modulation performance and the application of devices in photoelectric modulators and ultrafast switches etc. aspects. The project outcome will not only provide a theoretical basis for the design of THz wave modulation devices, but also play a positive role in promoting the development of high performance terahertz wave modulation and control devices.

太赫兹（Terahertz）波调控器件的匮乏是THz技术发展亟待解决的关键问题，而深入研究能与THz波发生有效作用的功能材料及器件是解决该问题的有效途径。二维材料石墨烯以其独特的载流子特性和优异的光电性能成为THz波调制器设计的理想材料。本项目以提高石墨烯对THz波的调制深度为目的，拟从理论和实验两个方面研究石墨烯自身特性如层数和掺杂水平、石墨烯-金属超材料及石墨烯超表面微结构在THz波段的电磁响应及光泵浦特性，建立它们与THz波相互作用的理论模型，揭示其调控THz波的物理机制，明确其影响THz波调控性能的基本规律，探索石墨烯在THz波段全光调制器、超快开关等领域的应用。本项目的研究成果不仅可以为THz波调制器件的设计提供一定的理论基础，也会对高性能太赫兹波调控器件的发展起到积极的推动作用。

太赫兹（Terahertz）波调控器件的匮乏是THz技术发展亟待解决的关键问题，石墨烯以其优异的光电性被认为是调控THz波最具潜力的理想材料之一。本项目利用太赫兹时域光谱系统研究了石墨烯在太赫兹波段的光学响应特性，并根据实验获取的太赫兹透射光谱，采用Drude模型得到石墨烯在太赫兹波段的电导率。设计了基于双层石墨烯带状结构的超材料，通过激发石墨烯中的等离子体实现宽带可调谐的带阻滤波效应，在中心频率1.2THz处的3dB的带宽为0.9THz。设计了基于石墨烯块状结构的超表面，利用阻抗匹配原理，实现了宽频带可调谐太赫兹吸波器，在1.11THz-2.61THz 频率范围内吸收率超过90%，相对吸收带宽达80.6%。设计了基于石墨烯花状结构超表面，实现了在0.68THz-1.63THz和3.34THz-4.08THz的双宽带可调谐太赫兹吸波，吸收率均超过90%，相对带宽分别为82.3%和20%。还设计了基于石墨烯双U结构的超表面，在2.7THz和8THz附近的太赫兹吸收率达90%以上。本项目的研究成果为太赫兹波调控器件的设计提供了一定的理论基础，丰富了基于石墨烯的太赫兹波调控器件，在一定程度上对高性能太赫兹波调控器件的发展也会起到较为积极的推动作用。