Analysis of long-range surface plasmon polaritons in nonlinear plasmonic waveguides using pseudospectral method

Abstract

A full-vectorial pseudospectral method is reported for solving the mode characteristics of nonlinear dielectric and plasmonic waveguides. The coupled equations are formulated in terms of transverse magnetic-field components, and self-consistent solutions are obtained through an iterative procedure. The proposed scheme applies in a saturable medium with biaxial anisotropy of practical interest. The accuracy and efficiency of this scheme are demonstrated by solving the mode bistability of a nonlinear dielectric optical waveguide, analyzed by the well-known finite-element-method-based imaginary-distance beam propagation method. Furthermore, the relationship between geometry and input power is studied by analyzing the power dispersion curve of the long-range surface plasmon polariton modes of a nonlinear plasmonic waveguide.

An Efficient Numerical Full-Vectorial Mode Solver Based on Fourier Series Expansion Method

“…To further confirm the accuracy of the proposed scheme, Table 4 lists the numerical results including the mode index n eff and the normalized propagation constant ðb ¼ n 2 eff À n 2 2 =n 2 1 À n 2 2 Þ obtained by the proposed method and by other available methods. The second waveguide under study named waveguide #2 (surface plasmon waveguide) is a rib-type waveguide with structural parameters same as waveguide #1, except that an Au film with thickness t au ¼ 10 nm and the refractive index n au ¼ 0:55 À j11:5 [32]- [34] (at wavelength ¼ 1550 nm) is deposited on top of the rib region. The converged refractive indices obtained by the proposed method in this case are n effNM ¼ 3:388540 À j0:000285 for full-vectorial TE Mode indices of the full-vectorial TM mode calculated by the commercial software BeamPROP using different discretizations for waveguide #1.…”