  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.
