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HL: Fachverband Halbleiterphysik

HL 82: Ultrafast Phenomena

HL 82.5: Vortrag

Donnerstag, 17. März 2011, 15:30–15:45, POT 251

Modulation of photoluminescence kinetics of InGaAs quantum dots embedded into a microcavity using picosecond acoustics — •C. Brüggemann¹, T. Berstermann¹, A.V. Scherbakov², M. Bombeck¹, S. Höfling³, C. Schneider³, A. Forchel³, A.V. Akimov², D.R. Yakovlev^1,2, and M. Bayer¹ — ¹Experimentelle Physik 2a, Technische Universität Dortmund, 44227 Dortmund, Germany — ²A.F. Ioffe Physical Technical Institute, Russian Institute of Sciences, 194021 St. Petersburg, Russia — ³Lehrstuhl für Technische Physik, Universität Würzburg, 97074 Würzburg, Germany

We use picosecond acoustics to modulate the photoluminescence (PL) kinetics of quantum dots (QDs) embedded into a microcavity (MC).

The distributed bragg reflector MC with a layer of In_0.3Ga_0.7As QDs at the center is grown on a GaAs(100) substrate. An Al-film has been evaporated on the backside. It is used to excite and inject a picosecond strain-pulse into the substrate, by illumination of the film with an intense femtosecond laser pulse. The strain pulse propagates through the substrate and reaches the cavity structure at a specific time after the PL excitation, which can be variably delayed. While the strain-pulse propagates through the MC the PL kinetics are perturbated, which is monitored by a streak camera in the time- and spectral domain.

We observe a strong modulation of the PL intensity under pulsed and steady state PL excitation conditions, due to the strain-pulse perturbation. In the latter case we are able to decrease the PL intensity by a factor of 20 and later increase it up to a factor of 6 for ∼100 ps.