@article{SchneiderGlazovKornetal.2018,
  author    = {Schneider, Christian and Glazov, Mikhail M. and Korn, Tobias and H{\"o}fling, Sven and Urbaszek, Bernhard},
  title     = {Two-dimensional semiconductors in the regime of strong light-matter coupling},
  series = {Nature Communications},
  volume    = {9},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-018-04866-6},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-231295},
  year      = {2018},
  abstract  = {The optical properties of transition metal dichalcogenide monolayers are widely dominated by excitons, Coulomb-bound electron-hole pairs. These quasi-particles exhibit giant oscillator strength and give rise to narrow-band, well-pronounced optical transitions, which can be brought into resonance with electromagnetic fields in microcavities and plasmonic nanostructures. Due to the atomic thinness and robustness of the monolayers, their integration in van der Waals heterostructures provides unique opportunities for engineering strong light-matter coupling. We review first results in this emerging field and outline future opportunities and challenges.},
  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}
}
@article{WaldherrLundtKlaasetal.2018,
  author    = {Waldherr, Max and Lundt, Nils and Klaas, Martin and Betzold, Simon and Wurdack, Matthias and Baumann, Vasilij and Estrecho, Eliezer and Nalitov, Anton and Cherotchenko, Evgenia and Cai, Hui and Ostrovskaya, Elena A. and Kavokin, Alexey V. and Tongay, Sefaattin and Klembt, Sebastian and H{\"o}fling, Sven and Schneider, Christian},
  title     = {Observation of bosonic condensation in a hybrid monolayer MoSe2-GaAs microcavity},
  series = {Nature Communications},
  volume    = {9},
  journal   = {Nature Communications},
  doi       = {10.1038/s41467-018-05532-7},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-233280},
  year      = {2018},
  abstract  = {Bosonic condensation belongs to the most intriguing phenomena in physics, and was mostly reserved for experiments with ultra-cold quantum gases. More recently, it became accessible in exciton-based solid-state systems at elevated temperatures. Here, we demonstrate bosonic condensation driven by excitons hosted in an atomically thin layer of MoSe2, strongly coupled to light in a solid-state resonator. The structure is operated in the regime of collective strong coupling between a Tamm-plasmon resonance, GaAs quantum well excitons, and two-dimensional excitons confined in the monolayer crystal. Polariton condensation in a monolayer crystal manifests by a superlinear increase of emission intensity from the hybrid polariton mode, its density-dependent blueshift, and a dramatic collapse of the emission linewidth, a hallmark of temporal coherence. Importantly, we observe a significant spin-polarization in the injected polariton condensate, a fingerprint for spin-valley locking in monolayer excitons. Our results pave the way towards highly nonlinear, coherent valleytronic devices and light sources.},
  language  = {en}
}