RTG 4

Nanophotonics/Plasmonics

Tomáš Šikola (CEITEC), Lukas Novotny (ETH), Yehiam Prior/Galad Hiran (WIS)

Plasmonic strong coupling

We investigate coupling between matter particles (excitons) and natural light-matter particles (plasmons), strong enough to give rise to a fully new species, so-called plexciton, that is neither matter nor light but shares the perks of both. To demonstrate plexcitons, we fabricate nanoscale optical antennas that focus light far better than traditional eyepieces and place with a nanometer precision another type of nanostructures, so-called quantum dots supporting the excitons, to the small area of maximum light enhancement. Plexcitons are expected to find application in novel communication and computation schemes (quantum information processing) and in controlling chemical reactions.

Second-harmonic generation with two-dimensional semiconductors

Second-harmonic generation is a process of doubling the frequency of light, with two base-frequency photons being converted into exactly one photon of doubled frequency. It is important for advanced optical setups and experiments, including precise metrology. However, it is also rather difficult to achieve and usually suffers from low conversion efficiency. We investigate a rare class of materials offering that fare much better than average in a second harmonic generation: atomically thin sheets of semiconductors. We utilize them to fabricate optical resonators tuned to the desired frequency for highly efficient frequency doubling of light.