Resonance fluorescence of semiconductor quantum dots: Signatures of the electron-phonon interaction

Using a fully quantized description of strongly confined electrons interacting with acoustic phonons and the photon field, the nonstationary resonance-fluorescence spectra of a semiconductor quantum dot are investigated. For excitation pulses with durations approaching typical electron-phonon scattering times, the virtual quantum processes yield an observable electron-phonon sideband broadening.

Figure 1

Resonance-fluorescence spectra (inset: absorption spectrum) without phonons (free) and with phonons ($T=4\mathrm{K}$, 40 K, 77 K) excited by the two Gaussian pulses [FWHM (a) $=50\mathrm{fs}$, (b) $=8\mathrm{ps}$], (c) polarizations, and (d) the population dynamics of the upper level.

Figure 2

Time development of the resonance-fluorescence spectra for (a) $t=10\mathrm{ps}$, (b) $t=100\mathrm{ps}$, and (c) the quasistationary spectrum without phonons (free) and with phonons at $T=77\mathrm{K}$ driven by the 8 ps Gaussian pulse.