Detuning-Dependent Mollow Triplet of a Coherently-Driven Single Quantum Dot

TL;DR

This paper investigates how phonon interactions affect the Mollow triplet in a coherently driven quantum dot, revealing a crossover between spectral broadening and narrowing with detuning, supported by both theory and experiments.

Contribution

It provides a fully analytical model including electron-phonon interactions and demonstrates excellent agreement with experimental data on detuning effects.

Findings

Spectral sidebands can broaden or narrow with detuning.

A crossover regime between broadening and narrowing is identified.

Theoretical predictions match experimental results closely.

Abstract

We present both experimental and theoretical investigations of a laser-driven quantum dot (QD) in the dressed-state regime of resonance fluorescence. We explore the role of phonon scattering and pure dephasing on the detuning-dependence of the Mollow triplet and show that the triplet sidebands may spectrally broaden or narrow with increasing detuning. Based on a polaron master equation approach which includes electron-phonon interaction nonperturbatively, we derive a fully analytical expression for the spectrum. With respect to detuning dependence, we identify a crossover between the regimes of spectral sideband narrowing or broadening. A comparison of the theoretical predictions to detailed experimental studies on the laser detuning-dependence of Mollow triplet resonance emission from single In(Ga)As QDs reveals excellent agreement.