Splitting of Surface Plasmon Frequencies of Metal Particles in a Nematic Liquid Crystal

TL;DR

This paper investigates how the surface plasmon resonance frequencies of small metallic particles are split when embedded in a nematic liquid crystal, providing theoretical calculations validated by experiments.

Contribution

It presents an exact calculation of the dielectric tensor and plasmon splitting in NLC suspensions, extending to higher concentrations with a generalized Maxwell-Garnett approximation.

Findings

Surface plasmon resonance splits into two polarized modes.

Theoretical splitting matches recent experimental observations.

Validated approximation methods for NLC-coated particles.

Abstract

We calculate the effective dielectric function for a suspension of small metallic particles immersed in a nematic liquid crystal (NLC) host. For a random suspension of such particles in the dilute limit, we calculate the effective dielectric tensor exactly and show that the surface plasmon (SP)resonance of such particles splits into two resonances, polarized parallel and perpendicular to the NLC director. At higher concentrations, we calculate this splitting using a generalized Maxwell-Garnett approximation, which can also be applied to a small metal particle coated with NLC. To confirm the accuracy of the MGA for NLC-coated spheres, we also use the Discrete Dipole Approximation. The calculated splitting is comparable to that observed in recent experiments on NLC-coated small metal particles