Dephasing of Mollow Triplet Sideband Emission of a Resonantly Driven Quantum Dot in a Microcavity

TL;DR

This study investigates how excitation-induced dephasing affects the spectral properties of resonance fluorescence from a quantum dot in a microcavity, revealing a quadratic broadening of Mollow triplet sidebands with increasing Rabi frequency.

Contribution

It provides experimental validation of a phonon-dressed quantum dot Mollow triplet model, highlighting the dephasing effects at large Rabi splittings in cavity-QED systems.

Findings

Spectral broadening of Mollow sidebands scales with the square of Rabi frequency.

Resonance fluorescence spectra match theoretical phonon-dressed models.

Dephasing effects are strongly dependent on optical driving power and detuning.

Abstract

Detailed properties of resonance fluorescence from a single quantum dot in a micropillar cavity are investigated, with particular focus on emission coherence in dependence on optical driving field power and detuning. Power-dependent series over a wide range could trace characteristic Mollow triplet spectra with large Rabi splittings of $|\Omega| \leq 15$ GHz. In particular, the effect of dephasing in terms of systematic spectral broadening $\propto \Omega^2$ of the Mollow sidebands is observed as a strong fingerprint of excitation-induced dephasing. Our results are in excellent agreement with predictions of a recently presented model on phonon-dressed QD Mollow triplet emission in the cavity-QED regime.