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. We also predict regimes of phonon-induced squeezing and anti-squeezing of the spectral resonances. 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.
Publication: Detuning-dependent Mollow triplet of a coherently-driven single quantum dot
Ata Ulhaq, Stefanie Weiler, Chiranjeeb Roy, Sven Marcus Ulrich, Michael Jetter, Stephen Hughes, and Peter Michler 
Optics Express Vol. 21, Iss. 4, pp. 4382–4395 (2013)
Contact person: Prof. Peter Michler