Original Article

Citation: Light: Science & Applications (2017) 6, e17030; doi:10.1038/lsa.2017.30
Published online 25 August 2017

Emission from quantum-dot high-β microcavities: transition from spontaneous emission to lasing and the effects of superradiant emitter coupling
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Sören Kreinberg1, Weng W Chow2, Janik Wolters1, Christian Schneider3, Christopher Gies4, Frank Jahnke4, Sven Höfling3,4, Martin Kamp3 and Stephan Reitzenstein1

  1. 1Institut für Festkörperphysik, Technische Universität Berlin, Berlin 10623, Germany
  2. 2Sandia National Laboratories, Albuquerque, NM 87185-1086, USA
  3. 3Lehrstuhl für Technische Physik, Universität Würzburg, Würzburg 97074, Germany
  4. 4School of Physics and Astronomy, University of St Andrews, St Andrews KY16 9SS, UK
  5. 5Institute for Theoretical Physics, University of Bremen, Bremen 28334, Germany

Correspondence: WW Chow, E-mail: wwchow@sandia.gov

Received 8 August 2016; Revised 26 February 2017; Accepted 26 February 2017
Accepted article preview online 28 February 2017

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Abstract

Measured and calculated results are presented for the emission properties of a new class of emitters operating in the cavity quantum electrodynamics regime. The structures are based on high-finesse GaAs/AlAs micropillar cavities, each with an active medium consisting of a layer of InGaAs quantum dots (QDs) and the distinguishing feature of having a substantial fraction of spontaneous emission channeled into one cavity mode (high β-factor). This paper demonstrates that the usual criterion for lasing with a conventional (low β-factor) cavity, that is, a sharp non-linearity in the input–output curve accompanied by noticeable linewidth narrowing, has to be reinforced by the equal-time second-order photon autocorrelation function to confirm lasing. The paper also shows that the equal-time second-order photon autocorrelation function is useful for recognizing superradiance, a manifestation of the correlations possible in high-β microcavities operating with QDs. In terms of consolidating the collected data and identifying the physics underlying laser action, both theory and experiment suggest a sole dependence on intracavity photon number. Evidence for this assertion comes from all our measured and calculated data on emission coherence and fluctuation, for devices ranging from light-emitting diodes (LEDs) and cavity-enhanced LEDs to lasers, lying on the same two curves: one for linewidth narrowing versus intracavity photon number and the other for g(2)(0) versus intracavity photon number.

Keywords:

coherence; laser physics; microlasers; nanolasers; optoelectronics; photon statistics; quantum dots; quantum optics