Engineering the phase speed of surface-plasmon wave at the planar interface of a metal and a chiral sculptured thin film

TL;DR

This paper demonstrates that the phase speed of surface-plasmon waves at a metal and chiral sculptured thin film interface can be engineered by adjusting the vapor incidence angle during fabrication, offering a simple control method.

Contribution

It introduces a method to control surface-plasmon wave phase speed via vapor deposition angle in a modified Kretschmann setup.

Findings

Phase speed depends on vapor incidence angle.

Phase speed can be engineered by fabrication parameters.

Surface-plasmon wave properties are tunable through film fabrication.

Abstract

The solution of a boundary-value problem formulated for a modified Kretschmann configuration shows that the phase speed of a surface-plasmon wave guided by the planar interface of a sufficiently thin metal film and a chiral sculptured thin film (STF) depends on the vapor incidence angle used while fabricating the chiral STF by physical vapor depoistion. Therefore, it may be possible to engineer the phase speed quite simply by selecting an appropriate value of the vapor deposition angle (in addition to the metal and the evaporant species).