Dresden 2014 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 54: Quantum light sources based on solid state systems: Status and visions II (Focus session with TT)
HL 54.4: Talk
Tuesday, April 1, 2014, 15:00–15:15, POT 251
Bright quantum dot single photon source based on a low Q defect cavity — •Sebastian Maier1, Peter Gold1, Alfred Forchel1, Niels Gregersen2, Sven Höfling1, 3, Christian Schneider1, and Martin Kamp1 — 1Technische Physik, Physikalisches Institut 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 — 3present address: SUPA, University of St Andrews, St Andrews, KY16 9SS, United Kingdom
Efficient light outcoupling in quantum dot single photon sources is critical and usually complicated resonator geometries, lithographic steps and spatial alignment are necessary. In this paper we demonstrate a quantum dot based quasi-planar single photon source with a high extraction efficiency of 42% measured with a numerical aperture of 0.7. Our sample was fabricated via molecular beam epitaxy (MBE) and contains a λ-thick cavity which is sandwiched between two distributed Bragg reflector (DBRs), consisting of 18 (5) bottom (top) layers of AlAs/GaAs mirror pairs. The high efficiency is caused by the self-aligned formation of oval defects on top of the quantum dots which is interesting for a possible scalable sample layout. Besides the high extraction efficiency the sample shows a high purity with a g2(0) value of 0.023. Due to the absence of any etched and exposed lateral semiconductor-air interfaces, such cavities are nearly ideal for spin manipulation and readout experiments.