基于石墨烯表面等离激元的混合型纳米并行线波导的模式分析

Mode Analysis of Hybrid Nanoparallel Wire Waveguides Based on Graphene Surface Plasmons

设计了一种由涂覆石墨烯的两根椭圆柱形和一根圆柱形电介质纳米线构成的基于石墨烯表面等离激元的纳米并行线波导。利用有限元方法,对波导所支持的5个最低阶模式的传输特性进行了分析。结果表明,波导所支持的这些模式均可由涂覆石墨烯的椭圆柱形和圆柱形电介质纳米线的基模和一阶模合成。工作波长或者石墨烯的费米能变化时,这些模式的传输特性的变化趋势保持一致。模式1和模式2的传输特性受椭圆柱纳米线半长轴、中心间距和圆柱纳米线的高度的影响相对较大。模式3的传输特性受结构参数的影响相对较小。模式4和模式5的传输特性受椭圆柱纳米线半长轴、中心间距和圆柱纳米线的半径的影响相对较大。本文设计的波导采用了椭圆柱形结构,增加了可调节的参数,其传输性能优于由涂覆石墨烯的三根圆柱形电介质纳米线构成的波导。本文设计的波导在微纳光学器件集成和传感器领域具有一定的应用前景。

A graphene surface plasmon-based nano-parallel wire waveguide composed of two elliptical cylindrical and one cylindrical dielectric nanowires coated with graphene is designed. Using the finite element method, the transmission characteristics of the five lowest-order modes supported by the waveguide are analyzed. The results show that these modes supported by the waveguide can be synthesized from the fundamental mode and the first-order mode of the graphene-coated elliptical cylindrical and cylindrical dielectric nanowires. When the working wavelength or the Fermi energy of graphene changes, the changing trend of the transmission characteristics of these modes remains the same. The transmission characteristics of mode 1 and mode 2 are relatively greatly affected by the semi-major axis of the elliptical cylindrical nanowire, the center distance, and the height of the cylindrical nanowire. The transmission characteristics of Mode 3 are relatively less affected by structural parameters. The transmission characteristics of mode 4 and mode 5 are relatively greatly affected by the semi-major axis of the elliptical cylindrical nanowire, the center distance, and the radius of the cylindrical nanowire. The waveguide designed in this paper adopts an elliptical cylindrical structure and increases adjustable parameters. Its transmission performance is better than that of a waveguide composed of three cylindrical dielectric nanowires coated with graphene. The waveguide designed in this paper has certain application prospects in the field of micro-nano optical device integration and sensors.