The electron–phonon coupling in self-assembled InGaAs quantum dots is relatively weak at low light intensities, which means that the zero-phonon line in emission is strong compared to the phonon sideband. However, the coupling to acoustic phonons can be dynamically enhanced in the presence of an intense optical pulse tuned within the phonon sideband. Recent experiments have shown that this dynamic vibronic coupling can enable population inversion to be achieved when pumping with a blueshifted laser and for rapid de-excitation of an inverted state with red detuning. In this paper we confirm the incoherent nature of the phonon-assisted pumping process and explore the temperature dependence of the mechanism. We also show that a combination of blueshifted and redshifted pulses can create and destroy an exciton within a timescale of ∼20 ps as determined by the pulse duration and ultimately limited by the phonon thermalization time.
|Number of pages
|Journal of the optical society of america b-Optical physics
|Published - 24 May 2016