cff-version: 1.2.0
abstract: "<p>We measure the local near-field spin in topological edge state waveguides that emulate the quantum spin Hall effect. We reveal a highly structured spin density distribution that is not linked to a unique pseudospin value. From experimental near-field real-space maps and numerical calculations, we confirm that this local structure is essential in understanding the properties of optical edge states and light-matter interactions. The global spin is reduced by a factor of 30 in the near field and, for certain frequencies, flipped compared to the pseudospin measured in the far field. We experimentally reveal the influence of higher-order Bloch harmonics in spin inhomogeneity, leading to a breakdown in the coupling between local helicity and global spin.</p>"
authors:
  - family-names: Arora
    given-names: Sonakshi
    orcid: "https://orcid.org/0000-0001-7333-6953"
  - family-names: Bauer
    given-names: Thomas
    orcid: "https://orcid.org/0000-0003-0887-4717"
  - family-names: Barczyk
    given-names: René
  - family-names: Verhagen
    given-names: Ewold
  - family-names: Kuipers
    given-names: L. (Kobus)
    orcid: "https://orcid.org/0000-0003-0556-8167"
title: "Data underlying the publication and chapter 3: Breakdown of spin-to-helicity locking at the nanoscale in topological photonic crystal edge states"
keywords:
version: 1
identifiers:
  - type: doi
    value: 10.4121/18779327.v1
license: CC0
date-released: 2023-07-24