Seminarium Fizyki Materii Skondensowanej

Microcavity polaritons are a hybrid photonic system arising from the strong coupling of confined photons to quantum-well excitons. Due to their light-matter nature, polaritons inherit a Kerr-like nonlinearity while being easily accessible by standard optical means. The ability to engineer confinement potentials in microcavities makes polaritons a very convenient system to study spatially localized bosonic populations in for example 0D dots, 1D chains, 2D lattices. A good example of this is the polariton Josephson junction which consists of two localized polariton populations coupled via tunneling. Careful engineering of this system is predicted to induce Gaussian squeezing, a phenomenon that lies at a heart of the so-called unconventional photon blockade associated with single photon emission. We reveal a manifestation of the predicted squeezing by measuring the ultrafast time-dependent second-order correlation function g(2)(0). The light emitted by the microcavity oscillates between Poissonian and super-Poissonian in phase with the Josephson dynamics. This behavior is remarkably well explained by quantum simulations, which predict a dynamical evolution of the squeezing parameters. Beyond this, we study in depth the dephasing mechanisms of the polariton populations and are beginning to explore a wide range of artificial structures.