發(fā)布時間：2018-09-12 09:02

【摘要】：石墨烯(Graphene)是一種由碳原子以sp2雜化軌道形成六角碳環(huán)的單原子厚度的二維材料。作為一種新型二維材料,它具有極高的電子遷移率,較好的透光率和機械強度。石墨烯在太赫茲和中遠紅外波段具有負的介電常數(shù),能很好地支持等離子體諧振。石墨烯等離子體諧振與入射波之間的相互作用能改變電磁波的電磁特性,因此周期性圖案化的石墨烯結(jié)構(gòu)可以作為超表面的單元結(jié)構(gòu)對空間波束進行調(diào)控。石墨烯的電導率具有可調(diào)性,能夠通過外加電壓等方式改變超表面的特性。本文從理論上研究了石墨烯超表面對空間波束的調(diào)控。本論文的主要研究內(nèi)容安排如下:1.石墨烯的結(jié)構(gòu)特性和石墨烯等離子體諧振的簡介;對目前超表面和石墨烯超表面的研究進展的綜述。2.研究了石墨烯的電磁特性——復表面電導率以及其在不同情況下的化簡形式;給出了石墨烯電導率的三種不同的調(diào)控方式;對石墨烯進行準確電磁建模并推導得到石墨烯的等效介電常數(shù)和表面阻抗。3.提出了能實現(xiàn)極化無關(guān)透明窗口的石墨烯互補超表面結(jié)構(gòu)。利用參數(shù)分析和數(shù)值模擬相結(jié)合的方法,給出了透明窗口產(chǎn)生的物理機理。討論了透明窗口的動態(tài)調(diào)控效果和窗口頻率附近的慢光效應(yīng)。4.開展了石墨烯超表面對空間波前調(diào)控的研究。根據(jù)費馬原理得到了二維異常透反射的公式;提出了能實現(xiàn)二維異常反射的石墨烯超表面結(jié)構(gòu);結(jié)合渦旋波和梯度超表面的概念,設(shè)計了能夠產(chǎn)生具有不同模式的渦旋波的石墨烯超表面。
[Abstract]:Graphene (Graphene) is a two-dimensional material with the thickness of a single atom formed by carbon atoms in sp2 hybrid orbitals to form hexagonal carbon rings. As a new two-dimensional material, it has high electron mobility, good transmittance and mechanical strength. Graphene has negative dielectric constant in terahertz and far-infrared band, which can support plasma resonance well. The interaction between graphene plasma resonance and incident wave can change the electromagnetic characteristics of electromagnetic wave, so the periodically patterned graphene structure can be used as a supersurface element structure to regulate the spatial beam. The conductivity of graphene is adjustable and can change the properties of supersurface by means of applied voltage. In this paper, the control of space beam by graphene supersurface is studied theoretically. The main research contents of this thesis are as follows: 1. A brief introduction to the structure of graphene and the plasma resonance of graphene. The electromagnetic charateristics of graphene, the complex surface conductivity and its simplified form under different conditions, are studied, and three different ways of controlling the conductivity of graphene are given. The equivalent dielectric constant and surface impedance of graphene were derived from the accurate electromagnetic modeling of graphene. The complementary supersurface structure of graphene which can realize polarization-independent transparent window is proposed. The physical mechanism of transparent window is given by using the method of parameter analysis and numerical simulation. The dynamic control effect of the transparent window and the slow light effect near the frequency of the window are discussed. The study on the spatial wave front regulation of graphene supersurface was carried out. According to Fermat's principle, the formula of two-dimensional abnormal reflection is obtained, the graphene supersurface structure which can realize two-dimensional abnormal reflection is proposed, and the concepts of vortex wave and gradient supersurface are combined. A graphene supersurface was designed to produce vortex waves of different modes.
【學位授予單位】：東南大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：O613.71
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本文編號：2238539