CM Seminar: Carlos Silva-Acuña – Institut Courtois & Département de physique, Université de Montréal

Title: Many-Body Exciton Polariton Quantum Dynamics in Optical Microcavities based on two-dimensional Metal-Halide Semiconductors

Abstract: Two-dimensional analogs of metal-halide perovskites represent a promising platform for exciton-polariton-based technologies. They sustain strongly bound excitons that are stable at room temperature, readily enabling strong light-matter coupling at ambient conditions. In the strong coupling limit, uncoupled excitons have been mainly regarded as a reservoir for the polariton population. In this work, we posit that there is a bidirectional interplay between the uncoupled exciton dynamics and the polariton quantum dynamics. We fabricated a Fabry-Pérot microcavity, enclosing a two-dimensional hybrid organic-inorganic lead-iodide semiconductor, and resolved the multi-particle correlations of exciton-polaritons — that is their population and coherence dynamics — employing excitation correlation photoluminescence and two-dimensional coherent excitation spectroscopies. We find (i) an increased exciton bimolecular scattering rate of the exciton reservoir in the microcavity relative to the bare semiconductor; (ii) ultrafast population transfer from the uncoupled exciton states and the middle polariton to the lower polariton; and (iii) two-quantum correlations between polaritons and uncoupled excitons. Our work quantifies many-body correlations between bare excitons and exciton-polaritons, which are fundamental in mechanisms of the formation of polariton condensates.

Speaker Bio: Carlos Silva-Acuña is the Director of the Courtois Institute and a Professor at the Department of Physics at Université de Montréal.