Chiral Surface Plasmon Polaritons on Metallic Nanowires

TL;DR

This paper demonstrates the generation and observation of chiral surface plasmon polaritons on metallic nanowires, showing their dependence on input polarization and nanowire properties, and highlights their potential as sources of circular polarized photons.

Contribution

It provides a theoretical and experimental study of chiral SPPs on nanowires, revealing their dependence on various parameters and their ability to produce circular polarized light.

Findings

Chiral SPPs can be excited by linearly polarized light at nanowire ends.

Chirality and spatial features depend on polarization angle, nanowire diameter, and environment.

Chiral SPPs can produce circular polarized photons in free space.

Abstract

Chiral surface plasmon polaritons (SPPs) can be generated by linearly polarized light incident at the end of a nanowire, exciting a coherent superposition of three specific nanowire waveguide modes. Images of chiral SPPs on individual nanowires obtained from quantum dot fluorescence excited by the SPP evanescent field reveal the chirality predicted in our theoretical model. The handedness and spatial extent of the helical periods of the chiral SPPs depend on the input polarization angle and nanowire diameter as well as the dielectric environment. Chirality is preserved in the free-space output wave, making a metallic nanowire a broad bandwidth subwavelength source of circular polarized photons.