Phonon-dressed Mollow triplet in the regime of cavity-QED

TL;DR

This paper investigates how phonon interactions affect the resonance fluorescence spectra of a driven quantum dot in a high-Q cavity, revealing complex broadening behaviors of the Mollow triplet peaks influenced by cavity coupling and phonon bath asymmetry.

Contribution

It introduces a polaron frame master equation approach to analyze phonon effects on Mollow triplet spectra in cavity-QED systems, highlighting the complex dependence on cavity coupling.

Findings

Spectral broadening of Mollow sidebands increases quadratically with Rabi frequency at small cavity coupling.

Broadening dependence becomes more complex at larger cavity coupling rates.

Asymmetry of the phonon bath influences the triplet peak sampling and broadening.

Abstract

We study the resonance fluorescence spectra of a driven quantum dot placed inside a high $Q$ semiconductor cavity and interacting with an acoustic phonon bath. The dynamics is calculated using a time-convolutionless master equation obtained in the polaron frame. We demonstrate pronounced spectral broadening of the Mollow sidebands through cavity-emission which, for small cavity-coupling rates, increases quadratically with the Rabi frequency. However, for larger cavity coupling rates, this broadening dependence is found to be more complex. This field-dependent Mollow triplet broadening is primarily a consequence of the triplet peaks sampling different parts of the asymmetric phonon bath, and agrees directly with recent experiments with semiconductor micropillars. The influence from the detuned cavity photon bath and multi-photon effects is shown to play a qualitatively important role on the fluorescence spectra.