A perspective on topological photonics in nanoscaled systems

Topology has become a powerful tool for controlling light and protecting photonic properties against imperfections. Most approaches in photonics have borrowed directly from condensed-matter analogies, but the nanoscale brings in subtleties that standard models often overlook: strong field confinement, nonlocality, and in particular the unavoidable leakage of light into the far-field.

Scientists have only begun to extend topological band theory to capture these uniquely nanophotonic effects. In particular, I emphasize the role of polarization and far-field radiation, and how polarization singularities could act as topological markers beyond the usual bulk observables. What should “topology in nanophotonics” really mean, and how can these ideas guide the design of the next generation of photonic devices?

Read my perspective here (also on arXiv).