2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/121634We study the momentum distribution and relaxation dynamics of semiconductor microcavity polaritons by angle-resolved and time-resolved spectroscopy. Above a critical pump level, the thermalization time of polaritons at positive detunings becomes shorter than their lifetime, and the polaritons form a quantum degenerate Bose-Einstein distribution in thermal equilibrium with the lattice.Updated with the published versionMesoscale and Nanoscale Physicstext