SFB 1238 | December 04, 15:30
Topological structures of and for light -surprises, tragedy and usefulness-
Topology is an invaluable tool to elucidate the properties of physical systems. Typically, it refers to instances where an entity has so‑called topological protection, which means that the entity cannot disappear if small changes are made to the system. In this lecture I will address two illustrations of topology relevant to light fields.
The first relates to optical singularities, which can have a topological charge, and a topological feature of guided light called transverse optical spin. I will experimentally show that the charge of both phase‑ and polarization singularities plays a role in how they are distributed in space and also in the way they are created and annihilated. Transverse optical spin can be exploited to affect quantum emission enabling the creation of a valley-photon interface. The second relates to the behavior of light in photonic nanostructures of which the properties have a non‑trivial topology. We experimentally investigated the propagation of edge states between topologically non‑trivial photonic crystals. I will show how the propagation direction is related to the far‑field optical spin of the modes, but also the breaking of helicity-momentum locking in the near-field. Time allowing I will discuss the creation of photonic Landau levels in strained photonic crystals.
FZJ
Contact: Paul van Loosdrecht