Project QuMat.1-TUD-4.1C in Pillar 4

Optical characterization of exciton-photon conversion and hybridization

Samples for ensemble optical spectroscopy and single-nanocrystal spectroscopy will be prepared. Due to the processibility of colloidal nanocrystals the substrate and other optical connections can be freely chosen. Therefore, Bi2Se3 nanocrystals can also be coupled to photonic nanostructures, like cavities and wave guides. We will employ both for far-field and near-field optical spectroscopy to interrogate both ensembles and single nanocrystals. Building on the spectroscopic information we will design dedicated nanostructures to maximize the light-matter interaction down to the individual topological nanocrystal (for bulk and for edge-related excitons), influencing radiative lifetimes and yielding ease of access to its photon statistics. Finally, we will study the transfer of electronic topological information (spin momentum coupled to linear momentum) to the photon state (photon polarization, and eventually also linear momentum) employing emerging concepts from nanophotonics, like optical spin-orbit coupling and transverse optical spin.