Faraday Rotation and One-Way Propagation of Plasmon Waves on a Nanoparticle Chain

TL;DR

This paper investigates how static magnetic fields and liquid crystalline environments influence plasmon wave propagation along nanoparticle chains, revealing Faraday rotation and directional propagation effects.

Contribution

It introduces a theoretical framework for calculating dispersion relations of plasmonic waves in nanoparticle chains within liquid crystals under magnetic fields, highlighting Faraday rotation and unidirectional propagation.

Findings

Finite Faraday rotation angle in nematic hosts.

Different dispersion relations for left- and right-moving waves in cholesteric hosts.

Potential for unidirectional plasmonic wave propagation at certain frequencies.

Abstract

We calculate the dispersion relations of plasmonic waves propagating along a chain of metallic nanoparticles in the presence of both a static magnetic field ${\bf B}$ and a liquid crystalline host. The dispersion relations are obtained using the quasistatic approximation and a dipole-dipole approximation to treat the interaction between surface plasmons on different nanoparticles. For a plasmons propagating along a particle chain in a nematic liquid crystalline host and a field parallel to the chain, we find a small, but finite, Faraday rotation angle. In a cholesteric liquid crystal host and an applied magnetic field parallel to the chain, the dispersion relations for left- and right-moving waves are found to be different. For some frequencies, the plasmonic wave may propagate only in one of the two directions.