Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 35: Ultrakurze Laserpulse: Anwendungen 2
Q 35.6: Vortrag
Mittwoch, 16. März 2011, 15:45–16:00, SCH A01
Time-resolved amplified spontaneous emission in quantum dots — Jordi Gomis-Bresco1, Sabine Dommers-Völkel1, Oliver Schöps1, •Yücel Kaptan1, Olga Dyatlova1, Dieter Bimberg2, and Ulrike Woggon1 — 1Institut für Optik und Atomare Physik, Technische Universität Berlin, Straße des 17. Juni 135, 10623 Berlin, Germany — 2Institut für Festkörperphysik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin, Germany
Complementary to prior pump-probe experiments the time-resolved amplified spontaneous emission (TRASE) of the excited state (ES) in InGaAs quantum dots-in-a-well (DWELL) based semiconductor optical amplifiers (SOAs) is studied by utilizing a Streak Camera System. The natural advantage of this approach is that we are able to directly resolve the population dynamics of the ES after the amplification of an ultrashort 150fs pulse resonant to the ground state (GS). Conducting the TRASE measurement when saturating the SOA we observe a 10ps delay between the nonlinear GS pulse amplification and the subsequent ES population drop-off [1]. It is well-known from pump-probe experiments that the GS population recovers in the time range of a few picoseconds. Assuming a cascade-like relaxation path (2D barrier-ES-GS) a corresponding fast decrease in the intensity of the ES ASE should be visible in the measurements. Since our observed 10ps delay contradicts this expectation, we conclude the dominance of a direct capture relaxation path (2D barrier-GS) in electrically pumped DWELL structures. [1] J. Gomis-Bresco et al., Appl. Phys. Lett. (accepted)