Mode analysis of plasmonic waveguides in planarly layered media

Abstract

Spectral properties of the modes supported by plasmonic waveguides in planarly layered media are studied by the method of Multiple MultiPoles (MMP). It is shown that the most important entities in the mode analysis are the wavenumbers of the upper and lowermost layers and the wavenumbers of the guided waves supported by the layered medium. These wavenumbers introduce branch points and associated branch cuts on the complex plane where the out-of-plane wavenumbers of the modes are searched. These branch points and associated cuts make the mode analysis in layered media more demanding than the mode analysis in homogeneous media, where there is only one branch point and associated branch cut related to the wavenumber of the homogeneous medium. Several numerical examples are given to address the differences introduced by the layered media in the mode analysis and guidelines that can be used in any well-known computational electromagnetics method are provided.

Keywords:

• Plasmonic waveguides
• layered media
• mode analysis
• eigenvalue analysis
• method of multiple multipoles (MMP)

Disclosure statement

No potential conflict of interest was reported by the author(s).