单介质加载双层石墨烯对称表面等离激元波导的理论分析  

Theoretical Analysis of Single Dielectric Loaded Two-Sheet Graphene Symmetric Surface Plasmon Waveguide

作　　者：李勇 张惠芳[1] 吴琼 何英[1] 王燕[1] Li Yong;Zhang Huifang;Wu Qiong;He Ying;Wang Yan(College of Sciences,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学理学院

出　　处：《激光与光电子学进展》2019年第20期167-175,共9页Laser & Optoelectronics Progress

基　　金：国家自然科学基金（11704241)

摘　　要：基于介质加载石墨烯等离激元波导(DLGPW),提出并研究了单介质加载双层石墨烯对称表面等离激元波导(DLTGSSPW)。在DLTGSSPW中,双层石墨烯中的表面等离激元(SPP)相互作用,形成耦合的SPP模,即对称和反对称SPP模。采用有效折射率法和有限元法进行研究,发现耦合的SPP模的有效折射率、传播损耗、模式数目及电场强烈地依赖于DLTGSSPW的参数,例如入射波长、单介质条的高度和宽度等。耦合的SPP模与三层介质平板波导中的导模很相似。另外,当单介质条的高度足够大时,在每层石墨烯中,耦合的对称和反对称SPP模退化成非耦合SPP模,DLTGSSPW可被看作两个独立的DLGPW。DLTGSSPW这种性质使其有望在集成光学器件中有潜在的应用价值。Based on a dielectric loaded graphene plasmon waveguide(DLGPW),this study proposes and investigates a single dielectric loaded two-sheet graphene symmetric surface plasmon waveguide(DLTGSSPW).In the DLTGSSPW,the interaction between the surface plasmon polaritons(SPPs)in two graphene sheets induces the coupled SPP modes,i.e.,the symmetric and anti-symmetric SPP modes.The effective index method and the finite element method are used to reveal that the effective mode refractive indexes,propagation losses,mode numbers,and electromagnetic fields of the coupled SPP modes are strongly dependent on the DLTGSSPW parameters,such as the incident wavelength and the width and height of a single dielectric strip.The coupled SPP modes are similar to the guided modes in a three-layer dielectric planar waveguide.In addition,when the single dielectric strip is sufficiently high,the symmetric and anti-symmetric SPPs degenerate into the uncouple SPP modes in the respective graphene sheets,and this structure can be considered as two independent DLGPWs.All the results about SPP waveguide may have some possible application in actively integrated optics.

关 键 词：表面光学 表面等离子激元 波导 有限元法 有效折射率法 石墨烯 

分 类 号：O436[机械工程—光学工程]