Research overview

An outstanding goal of solid-state quantum optics is the realization of a system of strongly interacting photons. To achieve this goal, we pursue two parallel avenues: first, we investigate different approaches for effecting tunable artifical gauge fields for photons. Second, we explore possibilities for enhancing photon-photon interactions. We have identified dipolar exciton-polaritons as a promising system to achieve these goals.

In 2D materials, interactions between excitons and itinerant electrons provide a rich playground for many-body physics. Strong exciton binding in these systems imply that excitons can be considered as robust quasi-particles even in the presence of degenerate electrons and holes. In the limit where the exciton density is much smaller than the free carrier density, elementary optical excitations are excitons dressed by electron-hole pair excitations out of a degenerate Fermi sea, termed exciton-(Fermi)-polarons. We have demonstrated that interaction between polarons can be up to a factor of 50 stronger than those between bare-excitons. In the opposite limit, electrons are dressed by Bogoluibov excitations out of an exciton or polariton condesate, forming electron-(Bose)-polarons. A key goal of the group is to use photonic dressing to enhance electron-electron interactions and thereby realize new electronic phases.