设计了一种高折射率基底的椭圆表面等离子体波导,基于有限元法对此波导支持的基模的能流密度分布、有效折射率、传播长度、 有效面积与几何参数、结构之间的关系进行了分析。能流密度分布表明能量主要集中分布在两个金属椭圆柱之间的中心区域,在金属与锗基底、基底与基底之间 也存在能量。通过调节两个椭圆的中心距离及其两个半轴的大小,可以实现此波导模式传输特性的分析。工作波长确定时有效折射率随中心距的增大而减小, 而传播长度增大。

An elliptical surface plasmonic waveguide with a high refractive index substrate is designed. Dependences of energy flux density distribution, effective refractive index, propagation length, effective area of the fundamental mode supported by the waveguide on the geometrical parameters and structure are analyzed based on the finite element method. The energy density distribution shows that the energy is mainly distributed in the central region between two metallic elliptical cylinders, and there is also energy between the metal and germanium substrate, the substrate and substrate. Propagation characteristics of the waveguide mode can be analyzed by adjusting the centric distance of two ellipses and size of two semiaxis. With constant working wavelength, the effective refractive index decreases with increasing of center distance, while the propagation length increases.