@article{SchlottmannSchickeKruegeretal.2019,
  author    = {Schlottmann, Elisabeth and Schicke, David and Kr{\"u}ger, Felix and Lingnau, Benjamin and Schneider, Christian and H{\"o}fling, Sven and L{\"u}dge, Kathy and Porte, Xavier and Reitzenstein, Stephan},
  title     = {Stochastic polarization switching induced by optical injection in bimodal quantum-dot micropillar lasers},
  series = {Optics Express},
  volume    = {27},
  journal   = {Optics Express},
  number    = {20},
  doi       = {10.1364/OE.27.028816},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-228603},
  pages     = {28816-28831},
  year      = {2019},
  abstract  = {Mutual coupling and injection locking of semiconductor lasers is of great interest in non-linear dynamics and its applications for instance in secure data communication and photonic reservoir computing. Despite its importance, it has hardly been studied in microlasers operating at mu W light levels. In this context, vertically emitting quantum dot micropillar lasers are of high interest. Usually, their light emission is bimodal, and the gain competition of the associated linearly polarized fundamental emission modes results in complex switching dynamics. We report on selective optical injection into either one of the two fundamental mode components of a bimodal micropillar laser. Both modes can lock to the master laser and influence the non-injected mode by reducing the available gain. We demonstrate that the switching dynamics can be tailored externally via optical injection in very good agreement with our theory based on semi-classical rate equations. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement},
  language  = {en}
}
@article{HolzingerSchneiderHoeflingetal.2019,
  author    = {Holzinger, Steffen and Schneider, Christian and H{\"o}fling, Sven and Porte, Xavier and Reitzenstein, Stephan},
  title     = {Quantum-dot micropillar lasers subject to coherent time-delayed optical feedback from a short external cavity},
  series = {Scientific Reports},
  volume    = {9},
  journal   = {Scientific Reports},
  doi       = {10.1038/s41598-018-36599-3},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-322485},
  year      = {2019},
  abstract  = {We investigate the mode-switching dynamics of an electrically driven bimodal quantum-dot micropillar laser when subject to delayed coherent optical feedback from a short external cavity. We experimentally characterize how the external cavity length, being on the same order than the microlaser's coherence length, influences the spectral and dynamical properties of the micropillar laser. Moreover, we determine the relaxation oscillation frequency of the micropillar by superimposing optical pulse injection to a dc current. It is found that the optical pulse can be used to disturb the feedback-coupled laser within one roundtrip time in such a way that it reaches the same output power as if no feedback was present. Our results do not only expand the understanding of microlasers when subject to optical feedback from short external cavities, but pave the way towards tailoring the properties of this key nanophotonic system for studies in the quantum regime of self-feedback and its implementation to integrated photonic circuits.},
  language  = {en}
}
@article{KreinbergPorteSchickeetal.2019,
  author    = {Kreinberg, S{\"o}ren and Porte, Xavier and Schicke, David and Lingnau, Benjamin and Schneider, Christian and H{\"o}fling, Sven and Kanter, Ido and L{\"u}dge, Kathy and Reitzenstein, Stephan},
  title     = {Mutual coupling and synchronization of optically coupled quantum-dot micropillar lasers at ultra-low light levels},
  series = {Nature Communications},
  volume    = {10},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-019-09559-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229811},
  year      = {2019},
  abstract  = {Synchronization of coupled oscillators at the transition between classical physics and quantum physics has become an emerging research topic at the crossroads of nonlinear dynamics and nanophotonics. We study this unexplored field by using quantum dot microlasers as optical oscillators. Operating in the regime of cavity quantum electrodynamics (cQED) with an intracavity photon number on the order of 10 and output powers in the 100 nW range, these devices have high β-factors associated with enhanced spontaneous emission noise. We identify synchronization of mutually coupled microlasers via frequency locking associated with a sub-gigahertz locking range. A theoretical analysis of the coupling behavior reveals striking differences from optical synchronization in the classical domain with negligible spontaneous emission noise. Beyond that, additional self-feedback leads to zero-lag synchronization of coupled microlasers at ultra-low light levels. Our work has high potential to pave the way for future experiments in the quantum regime of synchronization.},
  language  = {en}
}
@article{KreinbergGrbešićStraussetal.2018,
  author    = {Kreinberg, S{\"o}ren and Grbešić, Tomislav and Strauß, Max and Carmele, Alexander and Emmerling, Monika and Schneider, Christian and H{\"o}fling, Sven and Porte, Xavier and Reitzenstein, Stephan},
  title     = {Quantum-optical spectroscopy of a two-level system using an electrically driven micropillar laser as a resonant excitation source},
  series = {Light: Science \& Applications},
  volume    = {7},
  journal   = {Light: Science \& Applications},
  doi       = {10.1038/s41377-018-0045-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-229802},
  year      = {2018},
  abstract  = {Two-level emitters are the main building blocks of photonic quantum technologies and are model systems for the exploration of quantum optics in the solid state. Most interesting is the strict resonant excitation of such emitters to control their occupation coherently and to generate close to ideal quantum light, which is of utmost importance for applications in photonic quantum technology. To date, the approaches and experiments in this field have been performed exclusively using bulky lasers, which hinders the application of resonantly driven two-level emitters in compact photonic quantum systems. Here we address this issue and present a concept for a compact resonantly driven single-photon source by performing quantum-optical spectroscopy of a two-level system using a compact high-β microlaser as the excitation source. The two-level system is based on a semiconductor quantum dot (QD), which is excited resonantly by a fiber-coupled electrically driven micropillar laser. We dress the excitonic state of the QD under continuous wave excitation, and trigger the emission of single photons with strong multi-photon suppression (g\(^{(2)}\)(0)=0.02) and high photon indistinguishability (V = 57±9\%) via pulsed resonant excitation at 156 MHz. These results clearly demonstrate the high potential of our resonant excitation scheme, which can pave the way for compact electrically driven quantum light sources with excellent quantum properties to enable the implementation of advanced quantum communication protocols.},
  language  = {en}
}