Non-linear emission spectra of quantum dots strongly coupled to photonic mode

TL;DR

This paper develops a theoretical model describing the non-linear optical emission spectra of quantum dot arrays in microcavities, highlighting the transition from superradiant to lasing regimes as pumping increases.

Contribution

It introduces a new theory accounting for non-linear effects and the influence of quantum dot parity on emission spectra in strongly coupled quantum dot-cavity systems.

Findings

Emission spectra dominated by superradiant mode in linear regime

Destruction of superradiant mode in non-linear regime

Line width narrowing indicating lasing transition

Abstract

A theory of optical emission of quantum dot arrays in quantum microcavities is developed. The regime of the strong coupling between the quantum dots and photonic mode of the cavity is considered. The quantum dots are modeled as two-level systems. In the low pumping (linear) regime the emission spectra are mainly determined by the superradiant mode where the effective dipoles of the dots oscillate in phase. In the non-linear regime the superradiant mode is destroyed and the emission spectra are sensitive to the parity of quantum dot number. Further increase of the pumping results in the line width narrowing being an evidence of the lasing regime.