Grating-coupled excitation of multiple surface plasmon-polariton waves

TL;DR

This paper theoretically investigates how a surface-relief grating can excite multiple surface plasmon-polariton waves with different polarizations and phase speeds, using rigorous coupled-wave analysis.

Contribution

It introduces a theoretical framework for exciting multiple SPP waves with various polarizations and directions on a finite metal and rugate filter structure.

Findings

Multiple SPP waves can be excited with different polarizations.

Absorbance peaks indicate SPP excitation and vary with polarization.

Multiple incident waves can excite the same or different SPP modes.

Abstract

The excitation of multiple surface-plasmon-polariton (SPP) waves of different linear polarization states and phase speeds by a surface-relief grating formed by a metal and a rugate filter, both of finite thickness, was studied theoretically, using rigorous coupled-wave-analysis. The incident plane wave can be either p or s polarized. The excitation of SPP waves is indicated by the presence of those peaks in the plots of absorbance vs. the incidence angle that are independent of the thickness of the rugate filter. The absorbance peaks representing the excitation of s-polarized SPP waves are narrower than those representing p-polarized SPP waves. Two incident plane waves propagating in different directions may excite the same SPP wave. A line source could excite several SPP waves simultaneously.