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Fabrication of Single-Photon Sources by Use of Pyramidal Quantum-Dot Microcavities

  • Daniel Rülke
  • C. Reinheimer
  • D. M. Schaadt
  • H. Kalt
  • M. Hetterich
Conference paper
Part of the NATO Science for Peace and Security Series B: Physics and Biophysics book series (NAPSB)

Abstract

In recent years the interest in single-photon emitters for quantum-optical applications is strongly increasing. For this purpose, we have investigated In(Ga)As quantum-dots (QDs) embedded in reversed pyramidal GaAs microcavities (Fig. 52.1a). Even though it has been shown recently, that such cavities can act as high-Q optical resonators [1], our focus has been on the directional radiation of the QD emission due to reflection at the facets of the reversed pyramids. With QDs embedded close to the vertex of the four facets and a base angle adaptable between 35° and 55° the pyramids can be perceived as a kind of retroreflector. Since the QD layer is inserted near the tip of the predicted reversed pyramid during molecular-beam epitaxial (MBE) growth, the average number of QDs inside the cavity can be reduced to one, depending on the size of the pyramid and density of QDs. The pyramidal cavities are shaped after MBE growth by a wet-chemical etching process with a solution of H3PO4, H2O2 and H2O [2, 3].

Finite-element simulations have been performed to proof the ability of reversed pyra-mids to radiate the QD emission through the top surface and to prevent the emission from being lost into the substrate (Fig. 52.1b). For an optimized geometry we have calcula-ted, that radiation through the surface is more than two orders of magnitude higher than through the substrate.
Fig. 52.1

In order to analyze the radiation characteristics for continuous optical excitation, a Hanbury-Brown and Twiss setup has been used. The measured correlation function reveals a g(2)(0) of 0.26 which is sufficient to prove the single-photon character of the emitted light (Fig. 52.1c).

Keywords

Etching Process Optical Excitation Radiation Characteristic Directional Radiation Optical Resonator 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

References

  1. 1.
    Karl M et al (2010) Superlattice Microst 47(1):83–86ADSCrossRefGoogle Scholar
  2. 2.
    Weber FM et al (2007) Appl Phys Lett 90:161104ADSCrossRefGoogle Scholar
  3. 3.
    Karl M et al (2008) Appl Phys Lett 92:231105ADSCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2013

Authors and Affiliations

  • Daniel Rülke
    • 1
    • 2
  • C. Reinheimer
    • 1
  • D. M. Schaadt
    • 1
  • H. Kalt
    • 1
  • M. Hetterich
    • 1
  1. 1.Institut für Angewandte Physik, Center for Functional NanostructuresKarlsruhe Institute of Technology (KIT)KarlsruheGermany
  2. 2.Institute of Applied PhysicsKarlsruhe Institute of Technology (KIT)KarlsruheGermany

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