Non-equilibrium dynamics of polaritons in the quantum strong coupling regime

Date/Time: Mon. 2nd December 2013, 15:00-16:00 - (Seminar room 2005, National Institute of Informatics)

Speaker: Dr. Natsuko Ishida (RIKEN, Japan)

The Jaynes-Cummings model, describing the interaction between a single two-level system and a photonic mode, has been used to describe a large variety of systems, ranging from cavity quantum electrodynamics, trapped ions, to superconducting qubits coupled to resonators. Recently there has been interest in studying many body physics using extended Jaynes-Cummings model called Tavis-Cummings model. Here we focus on exciton-polaritons which are quasi-particles formed by superposition of excitons and photons. We examine the photoluminescence of highly-excited exciton-polariton condensates in semiconductor microcavities. Under strong pumping, exciton-polariton condensates have been observed to undergo a lasing transition where strong coupling between the excitons and photons is lost. We discuss an alternative high-density scenario, where the strong coupling is maintained. We find that the photoluminescence smoothly transitions between the lower polariton energy to the cavity photon energy. An intuitive understanding of the change in spectral characteristics will be discussed, as well as differences to the photoluminescence characteristics of the lasing case.