Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 60: Quantum dots: Optical properties I (with TT)
HL 60.4: Talk
Wednesday, April 2, 2014, 10:15–10:30, POT 251
Observation of carrier relaxation dynamics in Quantum Dot Excited State Laser — Holger Schmeckebier1, Dejan Arsenijevic1, Dieter Bimberg1, •Bastian Herzog2, Yücel Kaptan2, Nina Owschimikow2, Ulrike Woggon2, Vissarion Mikhelashvili3, and Gadi Eisenstein3 — 1Institute of Solid-State Physics, Technical University Berlin, Germany — 2Institute of Optics and Atomic Physics, Technical University Berlin, Germany — 3Electrical Engineering Dept. Technion - Israel Institute of Technology, Haifa, Israel
Single- and two-color Heterodyne pump-probe measurements were used to investigate the carrier dynamics of an InAs/InGaAs quantum dot based excited state laser at room temperature. Our main attention has been attracted by the excitonic ground state relaxation dynamics before and after the onset of excited state lasing, giving information about possible carrier relaxation paths. We found an ultrafast recovery with higher device currents, showing no change at and above the excited state lasing threshold. This could be an indication for a decoupling of the ground state gain recovery from the excited state gain dynamics. Two-color pump-probe experiments were performed to identify the excited state and ground state sub-ensemble belonging to the equal dot sub-ensemble.