Plasmonic Waves on a Chain of Metallic Nanoparticles: Combined Effects of a Liquid Crystalline Host and Static Magnetic Field

N. A. Pike, D. Stroud

Published 2015-02-17Version 1

We calculate the dispersion relations of plasmonic waves propagating along a chain of metallic nanoparticles in the presence of both a static magnetic field $ B$ and a liquid crystalline host. Our calculations use the quasistatic approximation and a dipole approximation for the interaction between plasmons on different nanoparticles. For $B$ parallel to the chain, and nematic liquid crystal (NLC) host with director $\hat{n}$ also parallel to the chain, the two transverse (T) branches consist of left- and right-circularly polarized waves with slightly different wave vectors for a given frequency. For $ B$ perpendicular and $\hat{n}$ parallel to the chain, the longitudinal (L) and one of the T branches mix to form two elliptically polarized waves. In the parallel orientation we find that a linearly polarized T wave undergoes Faraday rotation as it propagates along the chain. For parameters approximating that of a typical metal, and for a field of $2T$ parallel to the chain, the Faraday rotation is of order of microdegrees per ten interparticle spacings. For a cholesteric liquid crystal (CLC) host with $B$ parallel to the chain, left- and right-traveling modes propagating along the chain have slightly different dispersion relations. This opens up the possibility of one-way wave propagation at some frequencies. Possible extensions of our approach are briefly discussed.