Spin-Hall effect in the scattering of structured light from plasmonic nanowire

TL;DR

This paper demonstrates the Spin-Hall effect in the scattering of structured light from plasmonic nanowires, showing polarization-dependent asymmetry and enhancement with Hermite-Gaussian beams supported by numerical analysis.

Contribution

It reports the first observation of the Spin-Hall effect in scattering from plasmonic nanowires, highlighting the enhancement with Hermite-Gaussian beams and the role of spin flow in the effect.

Findings

Asymmetric scattering depends on polarization handedness.

Hermite-Gaussian beams show greater Spin-Hall effect than Gaussian beams.

Numerical simulations support experimental results.

Abstract

Spin-orbit interactions are subwavelength phenomena which can potentially lead to numerous device related applications in nanophotonics. Here, we report Spin-Hall effect in the forward scattering of Hermite-Gaussian and Gaussian beams from a plasmonic nanowire. Asymmetric scattered radiation distribution was observed for circularly polarized beams. Asymmetry in the scattered radiation distribution changes the sign when the polarization handedness inverts. We found a significant enhancement in the Spin-Hall effect for Hermite-Gaussian beam as compared to Gaussian beam for constant input power. The difference between scattered powers perpendicular to the long axis of the plasmonic nanowire was used to quantify the enhancement. In addition to it, nodal line of HG beam acts as the marker for the Spin-Hall shift. Numerical calculations corroborate experimental observations and suggest that the Spin flow component of Poynting vector associated with the circular polarization is responsible for the Spin-Hall effect and its enhancement.