Mollow quintuplets from coherently excited quantum dots

Abstract

Charge-neutral excitons in semiconductor quantum dots (QDs) have a small finite energy separation caused by the anisotropic exchange splitting. Coherent excitation of neutral excitons will generally excite both exciton components, unless the excitation is parallel to one of the dipole axes. We present a polaron master equation model to describe two-exciton pumping using a coherent continuous wave pump field in the presence of a realistic anisotropic exchange splitting. We predict a five-peak incoherent spectrum, namely a Mollow quintuplet under general excitation conditions. We experimentally confirm such spectral quintuplets for In(Ga)As QDs and obtain very good agreement with theory.