Surface-plasmon-polariton wave propagation guided by a metal slab in a sculptured nematic thin film

TL;DR

This theoretical study investigates how the thickness and orientation of a metal slab within a sculptured nematic thin film influence surface-plasmon-polariton wave propagation, coupling, and localization.

Contribution

It provides a detailed analysis of SPP wave behavior in a nonhomogeneous, twisted SNTF environment, highlighting the effects of slab thickness and interface coupling.

Findings

Thinner slabs increase interface coupling and SPP intensity.

Thicker slabs reduce coupling, localizing SPPs to a single interface.

Coupling strength inversely affects phase speed of SPP waves.

Abstract

Surface-plasmon-polariton~(SPP) wave propagation guided by a metal slab in a periodically nonhomogeneous sculptured nematic thin film~(SNTF) was studied theoretically. The morphologically significant planes of the SNTF on both sides of the metal slab could either be aligned or twisted with respect to each other. The canonical boundary-value problem was formulated, solved for SPP-wave propagation, and examined to determine the effect of slab thickness on the multiplicity and the spatial profiles of SPP waves. Decrease in slab thickness was found to result in more intense coupling of two metal/SNTF interfaces. But when the metal slab becomes thicker, the coupling between the two interfaces reduces and SPP waves localize to one of the two interfaces. The greater the coupling between the two metal/SNTF interfaces, the smaller is the phase speed.