Luminescence spectra of quantum dots in microcavities. I. Bosons

We provide a unified theory of luminescence spectra of coupled light-matter systems realized with semiconductor heterostructures in microcavities, encompassing (i) the spontaneous emission case, where the system decays from a prepared (typically pure) initial state, and (ii) luminescence in the presence of a continuous incoherent pump. We show how, by provoking a self-consistent quantum state, the pump considerably alters the emission spectra, even at vanishing intensities. The main outcome of our analysis is to unambiguously identify strong coupling in situations where it appears in disguise or only seems to appear. Here, we consider bosonic matter fields, in which case fully analytical solutions can be obtained. This describes the case of quantum wells or large quantum dots, or the limit of low excitation where the probability to have particles in the system remains much smaller than one.