Optical Signals to Monitor the Dynamics of Phonon‐Modified Rabi Oscillations in a Quantum Dot

Semiconductor quantum dots are solid state few‐level systems which can interact strongly with light. As such, they can be used as a single photon source or to perform solid‐state quantum‐optics experiments. A major difference to atoms is the interaction with the lattice vibrations, that is, the phonons, which strongly affect the optical signals from a quantum dot. In this paper, we calculate the time‐resolved pump‐probe signals from a continuously driven quantum dot accounting for detuned excitation and electron–phonon interaction. We provide analytical equations giving insight into the different phenomena observed in the spectra like an oscillation between absorptive and dispersive line shapes. For detuned excitation, the electron–phonon interaction can lead to phonon‐assisted occupation of the exciton, giving rise to a strong asymmetry in the dynamical behavior depending on the sign of the detuning. The time‐resolved spectra monitor this relaxation path, which helps understanding the effect of electron–phonon interaction in quantum dots. Semiconductor quantum dots under constant optical driving yield optical signals like in the Mollow triplet. Deriving and analyzing analytical equations for the probe signals for detuned excitation, the time‐dynamics shows an oscillatory behavior between absorptive and dispersive line‐shapes. Under the influence of phonons, the relaxation results in a probe signal consisting of two peaks.