Ultimate limit of field confinement by surface plasmon polaritons

TL;DR

This paper demonstrates that the fundamental limit of field confinement in surface plasmon polaritons is set by Landau damping, which cannot be overcome even with ideal materials, thus defining the ultimate confinement boundary.

Contribution

It provides a theoretical analysis showing Landau damping as an intrinsic limit to plasmonic confinement, independent of conventional loss mechanisms.

Findings

Landau damping directly limits field confinement in SPPs.

Eliminating conventional losses does not significantly improve confinement.

Maximum confinement is similar to that in the best existing plasmonic materials.

Abstract

We show that electric field confinement in surface plasmon polaritons propagating at the metal/dielectric interfaces enhances the loss due to Landau damping and which effectively limits the degree of confinement itself. We prove that Landau damping and associated with it surface collision damping follow directly from Lindhard formula for the dielectric constant of free electron gas Furthermore, we demonstrate that even if all the conventional loss mechanisms, caused by phonons, electron-electron, and interface roughness scattering, were eliminated, the maximum attainable degree of confinement and the loss accompanying it would not change significantly compared to the best existing plasmonic materials, such as silver.