Surface-plasmon-polariton waves guided by the uniformly moving planar interface of a metal film and dielectric slab

TL;DR

This study investigates how the relative motion of a metal-dielectric interface affects the excitation of surface-plasmon-polariton waves, revealing that motion speed and direction significantly influence excitation conditions and polarization dependence.

Contribution

It provides a detailed analysis of the impact of uniform motion on SPP wave excitation, incorporating Lorentz transformations and numerical simulations to reveal motion-dependent effects.

Findings

SPP excitation angle is highly sensitive to the ratio of motion speed to light speed and direction.

Polarization dependence varies with motion speed and direction, affecting SPP excitation.

Higher motion speeds can lead to breakdown of total reflection regimes.

Abstract

We explored the effects of relative motion on the excitation of surface-plasmon-polariton (SPP) waves guided by the planar interface of a metal film and a dielectric slab, both materials being isotropic and homogeneous. Electromagnetic phasors in moving and non-moving reference frames were related directly using the corresponding Lorentz transformations. Our numerical studies revealed that, in the case of a uniformly moving dielectric slab, the angle of incidence for SPP-wave excitation is highly sensitive to (i) the ratio $\beta$ of the speed of motion to speed of light in free space and (ii) the direction of motion. When the direction of motion is parallel to the plane of incidence, the SPP wave is excited by $p$-polarized (but not $s$-polarized) incident plane waves for low and moderate values of $\beta$, while at higher values of $\beta$ the total reflection regime breaks down. When the direction of motion is perpendicular to the plane of incidence, the SPP wave is excited by $p$-polarized incident plane waves for low values of $\beta$, but $s$-polarized incident plane waves at moderate values of $\beta$, while at higher values of $\beta$ the SPP wave is not excited. In the case of a uniformly moving metal film, the sensitivity to $\beta$ and the direction of motion is less obvious.