石墨烯准周期结构超表面的电磁吸收特性研究

发布时间：2019-02-11 19:13

【摘要】：石墨烯是一种具有广泛应用的二维结构材料,其在可见光和太赫兹波段的优良性质吸引了大量研究者的注意,也取得了丰富的成果。基于石墨烯结构的等离激元超表面研究的一个重要方面就是电磁吸收。本文结合新近发展起来的利用高维对称性改进的严格耦合波分析(RCWA)方法对一维和二维准周期结构的石墨烯图案超表面进行研究,讨论其太赫兹波段的电磁吸收特性。一维斐波拉契准周期序列结构和二维彭罗斯拼接结构均可以通过高维空间的剪切—投影方法获得,因此它们的频谱具有明显的对称性,这种特性使在傅立叶空间求解麦克斯韦方程及电磁波与物质相互作用的RCWA算法的优点凸显出来。结合高维空间中的Floquet理论,RCWA具有高效可靠的特点。对一维准周期石墨烯微带结构的仿真表明,与周期结构相比,准周期结构在同一频段具有更多的吸收峰,吸收峰的位置和强度与石墨烯带上产生的局域表面等离共振(LSPR)有关,结构吸收率对入射角的依赖不明显,通过改变石墨烯的化学势可以有效地调控结构的吸收工作波段。对二维准周期石墨烯微盘结构的仿真表明,结构在不同频段的吸收也与LSPR相关,在不同峰值吸收处LSPR的分布呈现出五重和十重对称性。结构对入射角的依赖也不明显,是一种宽角度入射吸收体的备选结构。
[Abstract]:Graphene is a widely used two-dimensional structure material. Its excellent properties in visible light and terahertz band have attracted the attention of a large number of researchers and have achieved a lot of results. Electromagnetic absorption is an important aspect in the study of isobaric supersurface based on graphene structure. In this paper, we study the graphene pattern supersurface of one-dimensional and two-dimensional quasi-periodic structures by using the newly developed strict coupled wave analysis (RCWA) method, which is improved in high dimensional symmetry, and discuss the electromagnetic absorption characteristics of the terahertz band. Both one-dimensional Fiberaci quasi-periodic sequence structure and two-dimensional Penrose splicing structure can be obtained by shear-projection method in high dimensional space, so their spectrum has obvious symmetry. This property highlights the advantages of the RCWA algorithm for solving Maxwell equation in Fourier space and the interaction between electromagnetic waves and matter. Combined with Floquet theory in high dimensional space, RCWA has the characteristics of high efficiency and reliability. The simulation of one-dimensional quasi-periodic graphene microstrip structure shows that the quasi-periodic structure has more absorption peaks than the periodic structure in the same frequency band. The position and intensity of the absorption peak are related to the local surface isodissociation resonance (LSPR) produced by the graphene band. The absorption rate of the structure is not dependent on the incident angle. The absorption band of the structure can be effectively regulated by changing the chemical potential of the graphene. The simulation of two-dimensional quasi-periodic graphene microdisk structure shows that the absorption of the structure in different frequency bands is also related to LSPR, and the distribution of LSPR at different peak absorption shows five and ten symmetries. The dependence of the structure on the incident angle is not obvious, and it is an alternative structure of the wide-angle incident absorber.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O613.71;O441

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