A closed-form solution to predict short-range surface plasmons in thin films and its application to hole arrays

TL;DR

This paper derives a simple closed-form solution for short-range surface plasmon polaritons in ultrathin metal films and validates it through simulations of hole arrays, advancing analytical modeling in plasmonics.

Contribution

It introduces a novel closed-form analytical solution for SR-SPPs in ultrathin films, simplifying the prediction of plasmonic behavior.

Findings

Analytical solution matches full-wave simulations for small holes

Excellent agreement between theory and simulation results

Provides a practical tool for designing plasmonic devices

Abstract

A theoretical study of surface plasmon polaritons (SPPs) in ultrathin lossy metal films is presented. The dispersion relation of such films is well known and can be solved numerically to obtain a combination of long-range (LR-) and short-range (SR-) eigenmodes. In this contribution, a simple solution for the SR-SPPs is derived. An approximation for the LR- eigenmodes can be found elsewhere. To validate the approximation, a two dimensional (2D) periodic array of small holes is studied subsequently. The spectral response of the array is obtained by full-wave simulations and the results compared with those calculated analytically, showing an excellent agreement for small holes.