%0 Generic
%A Arora, Sonakshi
%A Bauer, Thomas
%A Barczyk, René
%A Verhagen, Ewold
%A Kuipers, L. (Kobus)
%D 2023
%T Data underlying the publication and chapter 3: Breakdown of spin-to-helicity locking at the nanoscale in topological photonic crystal edge states
%U https://data.4tu.nl/articles/dataset/_/18779327
%R 10.4121/18779327.v1
%K Spin density maps
%K dispersion relation
%K SNOM tip
%K silicon-on-insulator waveguide structure
%K topological waveguides
%X <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>
%I 4TU.ResearchData