Analytical method for metal-insulator-metal surface plasmon polaritons waveguide networks

Metal-insulator-metal (MIM) surface plasmon polaritons (SPPs) waveguides with side-coupled resonators have been widely studied through various approaches. However, few methods are both physically transparent and complete. Here, an analytical approach, which is based on the Green’s function method, is developed in order to investigate electromagnetic wave transmission across SPPs MIM waveguide networks. The proposed method is applied in order to model different MIM-waveguide geometries with weakly-coupled side stubs, comparing to the geometries with strongly-coupled stubs. The weak coupling between the backbone and stubs is taken into account by the electromagnetic field leakage at metal-insulator interface. Analytical expressions for transmittance in cases of single stub and cavity are obtained straightforwardly. Our method shows excellent computational efficiency in contrast with solving Maxwell equations numerically.