Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 31: Poster II
HL 31.38: Poster
Dienstag, 26. Februar 2008, 16:30–19:00, Poster D
Measurements of the second order intensity correlation of quantum dots in GaAs/AlGaAs microcavities — •Marc Aßmann, Thorsten Berstermann, and Manfred Bayer — Experimentelle Physik II, TU Dortmund, 44221 Dortmund
The second order intensity correlation function g2 as defined by optical coherence theory is one of the main tools to classify photon emitters. We present g2-measurements of the emission of an ensemble of InGaAs quantum dots embedded as an active medium in high-Q micropillar laser structures. With increasing excitation density a transition into the lasing regime can be observed as a decrease of photon bunching from a value of g2(0)=1,84 towards a value of g2(0)=1. A change from Bose-Einstein statistics towards Poissonian statistics in the underlying photon number distribution can be seen as well. The results also show a strong dependence of the emission characteristics on the microcavity diameter. The experimental setup involves a streak camera which is modified such that a signal at fixed wavelength can be monitored after each pulsed laser excitation. The correlations are evaluated by averaging over an ensemble of such pulses. From these measurements insights into the quantum optical properties of light emission from semiconductor nanostructures can be taken.