Model of the optical emission of a driven semiconductor quantum dot: phonon-enhanced coherent scattering and off-resonant sideband narrowing

TL;DR

This paper investigates how the solid-state environment, especially phonons, influences the photon emission of driven quantum dots, revealing phonon-enhanced coherence and off-resonant spectral narrowing effects.

Contribution

It introduces a model showing phonon-induced enhancement of coherent emission and spectral narrowing in quantum dots under various driving conditions.

Findings

Phonon bath thermalization leads to increased coherent emission with stronger driving.

Coexistence of coherent scattering and Mollow triplet in resonance fluorescence.

Spectral sideband narrowing occurs off-resonance despite phonon effects.

Abstract

We study the crucial role played by the solid-state environment in determining the photon emission characteristics of a driven quantum dot. For resonant driving, we predict a phonon-enhancement of the coherently emitted radiation field with increasing driving strength, in stark contrast to the conventional expectation of a rapidly decreasing fraction of coherent emission with stronger driving. This surprising behaviour results from thermalisation of the dot with respect to the phonon bath, and leads to a nonstandard regime of resonance fluorescence in which significant coherent scattering and the Mollow triplet coexist. Off-resonance, we show that despite the phonon influence, narrowing of dot spectral sideband widths can occur in certain regimes, consistent with an experimental trend.