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HL: Fachverband Halbleiterphysik

HL 60: Quantum dots: Optical properties I (with TT)

HL 60.4: Vortrag

Mittwoch, 2. April 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.