Enhanced photonic spin Hall effect with subwavelength topological edge states

TL;DR

This paper demonstrates the enhancement of the photonic spin Hall effect using topologically protected edge states in subwavelength dielectric arrays, combining theoretical analysis with experimental validation in optics and microwaves.

Contribution

It introduces a novel approach to amplify the photonic spin Hall effect by leveraging topological edge states, supported by both theoretical insights and experimental evidence.

Findings

Enhanced spin Hall effect observed in topological edge states

Selective excitation controlled by light's handedness

Robustness of edge states against long-range coupling

Abstract

Photonic structures offer unique opportunities for controlling light-matter interaction, including the photonic spin Hall effect associated with the transverse spin-dependent displacement of light that propagates in specially designed optical media. However, due to small spin-orbit coupling, the photonic spin Hall effect is usually weak at the nanoscale. Here we suggest theoretically and demonstrate experimentally, in both optics and microwave experiments, the photonic spin Hall effect enhanced by topologically protected edge states in subwavelength arrays of resonant dielectric particles. Based on direct near-field measurements, we observe the selective excitation of the topological edge states controlled by the handedness of the incident light. Additionally, we reveal the main requirements to the symmetry of photonic structures to achieve a topology-enhanced spin Hall effect, and also analyse the robustness of the photonic edge states against the long-ranged coupling.