Berlin 2012 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 95: Quantum Dots and Wires: Optical Properties III (mainly Cavities and Ultrafast Response)
HL 95.3: Talk
Friday, March 30, 2012, 10:00–10:15, EW 201
Strong Quantum Dot - Cavity coupling in submicron diameter AlAs/GaAs micropillar cavities — •Matthias Lermer1, Niels Gregersen2, Florian Dunzer1, Jesper Mørk2, Stephan Reitzenstein1, Alfred Forchel1, Sven Höfling1, and Martin Kamp1 — 1Technische Physik and Wilhelm Conrad Röntgen Research Center for Complex Material Systems, Universität Würzburg, Am Hubland, D-97074 Würzburg, Germany — 2DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, Building 343, DK-2800 Kongens Lyngby, Denmark
Micropillar (MP) cavities with embedded quantum dots (QD) are a promising semiconductor based platform for the investigation and application of cavity quantum electrodynamic (cQED) effects, e.g. the strong QD - cavity coupling. A figure of merit for this regime is the ratio Q/sqrt(Vmode), expressing that it is preferable to realize MPs providing not only high Q factors but also small mode volumes Vmode. This puts stringent requirements to the design and the processing of the MPs, which show a drastic decrease of the Q factor in the low diameter limit due to sidewall scattering losses and mode mismatch. These effects limit Q to about 2,000 in the submicron diameter range. To overcome this problem, we have designed and implemented a novel AlAs/GaAs cavity design showing Q factors exceeding 10,000 for MPs with submicron diameters. A record-high vacuum Rabi splitting (VRS = 85 micro eV) of the strong coupling in MPs with modest oscillator strength QDs has been observed for a MP with Q = 13,600 and a diameter of 850 nm.