Signatures of dynamically dressed states

TL;DR

This paper reports the first experimental observation of the complete resonance fluorescence spectrum of a single quantum two-level system driven by pulsed excitation, revealing multiple sidebands and their dependence on pulse parameters.

Contribution

It provides the first experimental verification of theoretical predictions regarding the emission spectrum of dynamically dressed states in a quantum dot under pulsed excitation.

Findings

Multiple sidebands observed in the emission spectrum

Sideband number and spectral detuning increase with pulse intensity

Spectral shape and intensity depend on pulse length

Abstract

The interaction of a resonant light field with a quantum two-level system is of key interest both for fundamental quantum optics and quantum technological applications employing resonant excitation. While emission under resonant continuous-wave excitation has been well-studied, the more complex emission spectrum of dynamically dressed states, a quantum two-level system driven by resonant pulsed excitation, has so far been investigated in detail only theoretically. Here, we present the first experimental observation of the complete resonance fluorescence emission spectrum of a single quantum two-level system, in form of an excitonic transition in a semiconductor quantum dot, driven by finite Gaussian pulses. We observe multiple emerging sidebands as predicted by theory with an increase of their number and spectral detuning with excitation pulse intensity and a dependence of their spectral shape and intensity on the pulse length. Detuning-dependent measurements provide additional insights into the emission features. The experimental results are in excellent agreement with theoretical calculations of the emission spectra, corroborating our findings.