Analysis of pulse propagation through multilayer plasmonic waveguides in the quasi-bound mode region

Abstract

We present a numerical analysis of surface plasmon dispersion and the nonlinear nature of wave propagation on different smooth waveguides with lossy noble metal films. We also analyze the effective parameters that can affect the dispersion behavior of a thin dielectric slab waveguide embedded in a symmetric metal film. Three kinds of metal (silver, gold, and copper) with Johnson–Christy constants have been utilized in waveguides. Four kinds of dielectric material (air, Teflon, FR-4, and silicon) have been employed in the insulator layer of the metal–insulator–metal waveguide. The dispersion curve of the metal–insulator–metal waveguide with different metal and dielectric arrangements has been studied numerically. By multi-nominal fitting of dispersion curves, we have derived the nonlinear properties of Gaussian (chirped) wave propagation, dispersion length, and pulse broadening through a three-layer plasmonic waveguide. A comparison of three-layered plasmonic waveguides with different guiding layers has been accomplished. Simulation results have shown that dispersion curves with a larger peak and a quasi-bound mode cause the Gaussian waves to be dispersed and broadened during longer traveling distances. The achieved results serve an impressive function in the design of optical switches and delay lines.