Numerical solution of surface plasmon polariton mode propagating on spatially periodic metal-dielectric interface

To obtain the numerical solution of normal surface plasmon polariton (SPP) modes of free oscillations of the electromagnetic field on a cylindrical periodic dielectric-metal interface, a combination method is proposed by taking advantage of Green's function method and Chandezon's approach. With such methods, the dispersion curves and electromagnetic field distributions of SPP modes are calculated based on an Au-Si₃N₄ interface with both sinusoidal and symmetrical sawtooth shapes. The simulation results prove that the proposed method can be applied for calculating the electromagnetic field distribution of the SPP mode at an arbitrary wave vector along the dispersion curve and on arbitrary interface shapes. Furthermore, good stability and sufficient accuracy can be obtained with moderate frequency searching steps and a coefficients matrix order.