  Rare-earth doped nanocrystals are emerging light sources used for many
applications in nanotechnology enabled by human ability to control their
various optical properties with chemistry and material science. However, one
important optical problem -- polarisation of photoluminescence -- remains
largely out of control by chemistry methods. Control over photoluminescence
polarisation can be gained via coupling of emitters to resonant nanostructures
such as optical antennas and metasurfaces. However, the resulting polarization
is typically sensitive to position disorder of emitters, which is difficult to
mitigate. Recently, new classes of disorder-immune optical systems have been
explored within the framework of topological photonics. Here we explore
disorder-robust topological arrays of Mie-resonant nanoparticles for
polarisation control of photoluminescence of nanocrystals. We demonstrate
polarized emission from rare-earth-doped nanocrystals governed by photonic
topological edge states supported by zigzag arrays of dielectric resonators. We
verify the topological origin of polarised photoluminescence by comparing
emission from nanoparticles coupled to topologically trivial and nontrivial
arrays of nanoresonators.

Optics