Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 18: Semiconductor Lasers II
HL 18.3: Vortrag
Montag, 20. März 2017, 15:15–15:30, POT 06
Controlling the influence of background emitters on lasing in quantum dot micropillars — •Fabian Gericke1, Mawussey Segnon3, Martin von Helversen1, Tobias Heindel1, Christian Schneider2, Frank Jahnke3, Sven Höfling2, Anna Musial2, Xavier Porte2, Martin Kamp2, Christopher Gies3, and Stephan Reitzenstein1 — 1Institut für Festkörperphysik, Technische Universität Berlin, Germany — 2Technische Physik, Universität Würzburg, Germany — 3Institut für Theoretische Physik, Universität Bremen, Germany
In case of microlasers with a low number of quantum dots (QDs) acting as gain material, it is important to consider the relative gain contribution from individual QDs. In particular, in the single QD lasing regime one has to distinguish between the gain contribution of a single QD in resonance with the cavity mode and that of additional off-resonant emitters. In this regime, we control and study the relative gain contribution of the resonant QD and a small ensemble of non-resonant QDs by using a two-color excitation scheme. The experiments are supported by a theoretical description in which we describe the system using a microscopic semiconductor model. This enables us to discriminate a truly single QD laser from a device where lasing threshold is enabled by additional background emitters. We show that a single QD in the spontaneous emission regime contributes with up to 70% to the laser output. Interestingly, increasing the number of contributing off-resonant emitters changes the effective beta-factor and lowers the laser threshold.