Excitonic dynamics in a single quantum dot within a microcavity

The excitonic dynamics in a single quantum dot within a microcavity is investigated theoretically in terms of the perturbation treatment based on a unitary transformation. The excitonic Rabi oscillations with a damping rate are obtained explicitly. It is shown that the damping rate depends on exciton-phonon coupling constant and the vacuum Rabi frequency. Even at absolute zero temperature and in the vacuum cavity, the exciton-phonon interaction and exciton-photon interaction still cause excitonic decoherence. We also predict that under strong control fields the collapse and revival of excitonic Rabi oscillation may be observed for the quantum dots with small exciton-phonon coupling in the $T\to 0$ limit.

Figure 1

The population inversion as a function of time for four exciton-phonon coupling constants [in unit of ${\left(\mathrm{ps}\right)}^2$] while ${\Omega }_c=1.0{\omega }_l$ and $g=0.2{\omega }_l$.

Figure 2

The population inversion as a function of time for three Rabi frequencies (in unit of ${\omega }_l$) of the external control field while $\alpha =0.05{\left(\mathrm{ps}\right)}^2$ and $g=0.2{\omega }_l$.

Figure 3

The vacuum damping rate as a function of exciton-phonon coupling constant $\alpha$ (solid curve, $g=0.2{\omega }_l$) or the vacuum Rabi frequency $g$ [dashed curve, $\alpha =0.1{\left(\mathrm{ps}\right)}^2$].