Asymmetric coupling and dispersion of surface-plasmon-polariton waves on a periodically patterned anisotropic metal film

TL;DR

This paper investigates how a patterned anisotropic silver film influences surface plasmon-polariton waves, revealing asymmetric coupling and hyperbolic dispersion effects through experimental and homogenization analyses.

Contribution

It demonstrates the asymmetric coupling of SPP waves on patterned anisotropic silver films and models their dispersion using the Bruggeman formalism.

Findings

Strong blazing action observed in patterned films.

Asymmetric coupling of SPP waves along specific directions.

Dispersion characterized as hyperbolic via homogenization.

Abstract

The morphology of a columnar thin film (CTF) of silver renders it an effectively biaxially anisotropic continuum. CTFs of silver deposited on one-dimensional gratings of photoresist showed strong blazing action and asymmetrically coupled optical radiation to surface plasmon-polariton (SPP) waves propagating only along one direction supported by either the CTF/photoresist or the CTF/air interfaces. Homogenization of the CTFs using the Bruggeman formalism revealed them to display hyperbolic dispersion, and the dispersion of SPP waves was adequately described thereby.