Luminescence Spectra of Quantum Dots in Microcavities. I. Bosons

TL;DR

This paper develops a unified theoretical framework for luminescence spectra of semiconductor microcavity systems, analyzing effects of incoherent pumping and identifying strong-coupling regimes with analytical solutions for bosonic matter fields.

Contribution

It introduces a comprehensive theory that includes incoherent pumping effects on luminescence spectra, clarifies the conditions for strong-coupling, and provides analytical solutions for bosonic systems.

Findings

Incoherent pump significantly alters emission spectra.

Strong-coupling can be hidden or only apparent without proper analysis.

Analytical solutions are obtained for bosonic matter fields.

Abstract

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. While the former case has been amply discussed in the literature (albeit mainly for the case of resonance), no consideration has been given to the influence of the 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 average populations remain much smaller than one.