@article{TempelVeitAssmannetal.2012,
  author    = {Tempel, Jean-Sebastian and Veit, Tempel and Assmann, Marc and Kreilkamp, Lars Erik and H{\"o}fling, Sven and Kamp, Martin and Forchel, Alfred and Bayer, Manfred},
  title     = {Temperature dependence of pulsed polariton lasing in a GaAs microcavity},
  series = {New Journal of Physics},
  volume    = {14},
  journal   = {New Journal of Physics},
  number    = {083014},
  doi       = {10.1088/1367-2630/14/8/083014},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134022},
  year      = {2012},
  abstract  = {The second-order correlation function g\(^2\)(\(\tau\) = 0), input-output curves and pulse duration of the emission from a microcavity exciton-polariton system subsequent to picosecond-pulsed excitation are measured for different temperatures. At low temperatures a two-threshold behaviour emerges, which has been attributed to the onset of polariton lasing and conventional lasing at the first and the second threshold, respectively. We observe that polariton lasing is stable up to temperatures comparable with the exciton binding energy. At higher temperatures a single threshold displays the direct transition from thermal emission to photon lasing.},
  language  = {en}
}
@article{AmthorWeissenseelFischeretal.2014,
  author    = {Amthor, Matthias and Weißenseel, Sebastian and Fischer, Julian and Kamp, Martin and Schneider, Christian and H{\"o}fling, Sven},
  title     = {Electro-optical switching between polariton and cavity lasing in an InGaAs quantum well microcavity},
  doi       = {10.1364/OE.22.031146},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-111130},
  year      = {2014},
  abstract  = {We report on the condensation of microcavity exciton polaritons under optical excitation in a microcavity with four embedded InGaAs quantum wells. The polariton laser is characterized by a distinct nonlinearity in the input-output-characteristics, which is accompanied by a drop of the emission linewidth indicating temporal coherence and a characteristic persisting emission blueshift with increased particle density. The temporal coherence of the device at threshold is underlined by a characteristic drop of the second order coherence function to a value close to 1. Furthermore an external electric field is used to switch between polariton regime, polariton condensate and photon lasing.},
  language  = {en}
}
@article{MaierGoldForcheletal.2014,
  author    = {Maier, Sebastian and Gold, Peter and Forchel, Alfred and Gregersen, Niels and Mork, Jesper and H{\"o}fling, Sven and Schneider, Christian and Kamp, Martin},
  title     = {Bright single photon source based on self-aligned quantum dot-cavity systems},
  series = {Optics Express},
  volume    = {22},
  journal   = {Optics Express},
  number    = {7},
  issn      = {1094-4087},
  doi       = {10.1364/OE.22.008136},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119801},
  pages     = {8136-42},
  year      = {2014},
  abstract  = {We report on a quasi-planar quantum-dot-based single-photon source that shows an unprecedented high extraction efficiency of 42\% without complex photonic resonator geometries or post-growth nanofabrication. This very high efficiency originates from the coupling of the photons emitted by a quantum dot to a Gaussian shaped nanohill defect that naturally arises during epitaxial growth in a self-aligned manner. We investigate the morphology of these defects and characterize the photonic operation mechanism. Our results show that these naturally arising coupled quantum dot-defects provide a new avenue for efficient (up to 42\% demonstrated) and pure (g(2)(0) value of 0.023) single-photon emission.},
  language  = {en}
}
@article{RauHeindelUnsleberetal.2014,
  author    = {Rau, Markus and Heindel, Tobias and Unsleber, Sebastian and Braun, Tristan and Fischer, Julian and Frick, Stefan and Nauerth, Sebastian and Schneider, Christian and Vest, Gwenaelle and Reitzenstein, Stephan and Kamp, Martin and Forchel, Alfred and H{\"o}fling, Sven and Weinfurter, Harald},
  title     = {Free space quantum key distribution over 500 meters using electrically driven quantum dot single-photon sources-a proof of principle experiment},
  series = {New Journal of Physics},
  volume    = {16},
  journal   = {New Journal of Physics},
  number    = {043003},
  doi       = {10.1088/1367-2630/16/4/043003},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116760},
  year      = {2014},
  abstract  = {Highly efficient single-photon sources (SPS) can increase the secure key rate of quantum key distribution (QKD) systems compared to conventional attenuated laser systems. Here we report on a free space QKD test using an electrically driven quantum dot single-photon source (QD SPS) that does not require a separate laser setup for optical pumping and thus allows for a simple and compact SPS QKD system. We describe its implementation in our 500 m free space QKD system in downtown Munich. Emulating a BB84 protocol operating at a repetition rate of 125 MHz, we could achieve sifted key rates of 5-17 kHz with error ratios of 6-9\% and g((2))(0)-values of 0.39-0.76.},
  language  = {en}
}
@article{WinklerFischerSchadeetal.2015,
  author    = {Winkler, Karol and Fischer, Julian and Schade, Anne and Amthor, Matthias and Dall, Robert and Geßler, Jonas and Emmerling, Monika and Ostrovskaya, Elena A. and Kamp, Martin and Schneider, Christian and H{\"o}fling, Sven},
  title     = {A polariton condensate in a photonic crystal potential landscape},
  series = {New Journal of Physics},
  volume    = {17},
  journal   = {New Journal of Physics},
  doi       = {10.1088/1367-2630/17/2/023001},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-125050},
  pages     = {023001},
  year      = {2015},
  abstract  = {The possibility of investigating macroscopic coherent quantum states in polariton condensates and of engineering polariton landscapes in semiconductors has triggered interest in using polaritonic systems to simulate complex many-body phenomena. However, advanced experiments require superior trapping techniques that allow for the engineering of periodic and arbitrary potentials with strong on-site localization, clean condensate formation, and nearest-neighbor coupling. Here we establish a technology that meets these demands and enables strong, potentially tunable trapping without affecting the favorable polariton characteristics. The traps are based on a locally elongated microcavity which can be formed by standard lithography. We observe polariton condensation with non-resonant pumping in single traps and photonic crystal square lattice arrays. In the latter structures, we observe pronounced energy bands, complete band gaps, and spontaneous condensation at the M-point of the Brillouin zone.},
  language  = {en}
}
@article{MotykaSękRyczkoetal.2015,
  author    = {Motyka, Marcin and Sęk, Grzegorz and Ryczko, Krzysztof and Dyksik, Mateusz and Weih, Robert and Patriarche, Gilles and Misiewicz, Jan and Kamp, Martin and H{\"o}fling, Sven},
  title     = {Interface Intermixing in Type II InAs/GaInAsSb Quantum Wells Designed for Active Regions of Mid-Infrared-Emitting Interband Cascade Lasers},
  series = {Nanoscale Research Letters},
  volume    = {10},
  journal   = {Nanoscale Research Letters},
  number    = {471},
  doi       = {10.1186/s11671-015-1183-x},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-136386},
  year      = {2015},
  abstract  = {The effect of interface intermixing in W-design GaSb/AlSb/InAs/Ga\(_{0.665}\)In\(_{0.335}\)As\(_x\)Sb\(_{1-x}\)/InAs/AlSb/GaSb quantum wells (QWs) has been investigated by means of optical spectroscopy supported by structural data and by band structure calculations. The fundamental optical transition has been detected at room temperature through photoluminescence and photoreflectance measurements and appeared to be blueshifted with increasing As content of the GaInAsSb layer, in contrast to the energy-gap-driven shifts calculated for an ideally rectangular QW profile. The arsenic incorporation into the hole-confining layer affects the material and optical structure also altering the InAs/GaInAsSb interfaces and their degree of intermixing. Based on the analysis of cross-sectional transmission electron microscopy images and energy-dispersive X-ray spectroscopy, we could deduce the composition distribution across the QW layers and hence simulate more realistic confinement potential profiles. For such smoothed interfaces that indicate As-enhanced intermixing, the energy level calculations have been able to reproduce the experimentally obtained trend.},
  language  = {en}
}
@article{DyksikMotykaSęketal.2015,
  author    = {Dyksik, Mateusz and Motyka, Marcin and Sęk, Grzegorz and Misiewicz, Jan and Dallner, Matthias and Weih, Robert and Kamp, Martin and H{\"o}fling, Sven},
  title     = {Submonolayer Uniformity of Type II InAs/GaInSb W-shaped Quantum Wells Probed by Full-Wafer Photoluminescence Mapping in the Mid-infrared Spectral Range},
  series = {Nanoscale Research Letters},
  volume    = {10},
  journal   = {Nanoscale Research Letters},
  number    = {402},
  doi       = {10.1186/s11671-015-1104-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-139733},
  year      = {2015},
  abstract  = {The spatial uniformity of GaSb- and InAs substrate-based structures containing type II quantum wells was probed by means of large-scale photoluminescence (PL) mapping realized utilizing a Fourier transform infrared spectrometer. The active region was designed and grown in a form of a W-shaped structure with InAs and GaInSb layers for confinement of electrons and holes, respectively. The PL spectra were recorded over the entire 2-in. wafers, and the parameters extracted from each spectrum, such as PL peak energy position, its linewidth and integrated intensity, were collected in a form of two-dimensional spatial maps. Throughout the analysis of these maps, the wafers' homogeneity and precision of the growth procedure were investigated. A very small variation of PL peak energy over the wafer indicates InAs quantum well width fluctuation of only a fraction of a monolayer and hence extraordinary thickness accuracy, a conclusion further supported by high uniformity of both the emission intensity and PL linewidth.},
  language  = {en}
}
@article{YuNatarajanHorikirietal.2015,
  author    = {Yu, Leo and Natarajan, Chandra M. and Horikiri, Tomoyuki and Langrock, Carsten and Pelc, Jason S. and Tanner, Michael G. and Abe, Eisuke and Maier, Sebastian and Schneider, Christian and H{\"o}fling, Sven and Kamp, Martin and Hadfield, Robert H. and Fejer, Martin M. and Yamamoto, Yoshihisa},
  title     = {Two-photon interference at telecom wavelengths for time-bin-encoded single photons from quantum-dot spin qubits},
  series = {Nature Communications},
  volume    = {6},
  journal   = {Nature Communications},
  doi       = {10.1038/ncomms9955},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-138677},
  pages     = {8955},
  year      = {2015},
  abstract  = {Practical quantum communication between remote quantum memories rely on single photons at telecom wavelengths. Although spin-photon entanglement has been demonstrated in atomic and solid-state qubit systems, the produced single photons at short wavelengths and with polarization encoding are not suitable for long-distance communication, because they suffer from high propagation loss and depolarization in optical fibres. Establishing entanglement between remote quantum nodes would further require the photons generated from separate nodes to be indistinguishable. Here, we report the observation of correlations between a quantum-dot spin and a telecom single photon across a 2-km fibre channel based on time-bin encoding and background-free frequency downconversion. The downconverted photon at telecom wavelengths exhibits two-photon interference with another photon from an independent source, achieving a mean wavepacket overlap of greater than 0.89 despite their original wavelength mismatch (900 and 911 nm). The quantum-networking operations that we demonstrate will enable practical communication between solid-state spin qubits across long distances.},
  language  = {en}
}
@article{LeeSongHanetal.2015,
  author    = {Lee, Eun-Hye and Song, Jin-Dong and Han, Il-Ki and Chang, Soo-Kyung and Langer, Fabian and H{\"o}fling, Sven and Forchel, Alfred and Kamp, Martin and Kim, Jong-Su},
  title     = {Structural and optical properties of position-retrievable low-density GaAs droplet epitaxial quantum dots for application to single photon sources with plasmonic optical coupling},
  series = {Nanoscale Research Letters},
  volume    = {10},
  journal   = {Nanoscale Research Letters},
  number    = {114},
  doi       = {10.1186/s11671-015-0826-2},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-143692},
  year      = {2015},
  abstract  = {The position of a single GaAs quantum dot (QD), which is optically active, grown by low-density droplet epitaxy (DE) (approximately 4 QDs/μm\(^{2}\)), was directly observed on the surface of a 45-nm-thick Al\(_{0.3}\)Ga\(_{0.7}\)As capping layer. The thin thickness of AlGaAs capping layer is useful for single photon sources with plasmonic optical coupling. A micro-photoluminescence for GaAs DE QDs has shown exciton/biexciton behavior in the range of 1.654 to 1.657 eV. The direct observation of positions of low-density GaAs DE QDs would be advantageous for mass fabrication of devices that use a single QD, such as single photon sources.},
  language  = {en}
}
@article{LeeLimSchneideretal.2015,
  author    = {Lee, Chang-Min and Lim, Hee-Jin and Schneider, Christian and Maier, Sebastian and H{\"o}fling, Sven and Kamp, Martin and Lee, Yong-Hee},
  title     = {Efficient single photon source based on \(\mu\)-fibre-coupled tunable microcavity},
  series = {Scientific Reports},
  volume    = {5},
  journal   = {Scientific Reports},
  number    = {14309},
  doi       = {10.1038/srep14309},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-145835},
  year      = {2015},
  abstract  = {Efficient and fast on-demand single photon sources have been sought after as critical components of quantum information science. We report an efficient and tunable single photon source based on an InAs quantum dot (QD) embedded in a photonic crystal cavity coupled with a highly curved \(\mu\)-fibre. Exploiting evanescent coupling between the \(\mu\)-fibre and the cavity, a high collection efficiency of 23\% and Purcell-enhanced spontaneous emissions are observed. In our scheme, the spectral position of a resonance can be tuned by as much as 1.5 nm by adjusting the contact position of the \(\mu\)-fibre, which increases the spectral coupling probability between the QD and the cavity mode. Taking advantage of the high photon count rate and the tunability, the collection efficiencies and the decay rates are systematically investigated as a function of the QD-cavity detuning.},
  language  = {en}
}
@article{KimZhangWangetal.2016,
  author    = {Kim, Seonghoon and Zhang, Bo and Wang, Zhaorong and Fischer, Julian and Brodbeck, Sebastian and Kamp, Martin and Schneider, Christian and H{\"o}fling, Sven and Deng, Hui},
  title     = {Coherent Polariton Laser},
  series = {Physical Review X},
  volume    = {6},
  journal   = {Physical Review X},
  number    = {011026},
  doi       = {10.1103/PhysRevX.6.011026},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166597},
  year      = {2016},
  abstract  = {The semiconductor polariton laser promises a new source of coherent light, which, compared to conventional semiconductor photon lasers, has input-energy threshold orders of magnitude lower. However, intensity stability, a defining feature of a coherent state, has remained poor. Intensity noise many times the shot noise of a coherent state has persisted, attributed to multiple mechanisms that are difficult to separate in conventional polariton systems. The large intensity noise, in turn, limits the phase coherence. Thus, the capability of the polariton laser as a source of coherence light is limited. Here, we demonstrate a polariton laser with shot-noise-limited intensity stability, as expected from a fully coherent state. This stability is achieved by using an optical cavity with high mode selectivity to enforce single-mode lasing, suppress condensate depletion, and establish gain saturation. Moreover, the absence of spurious intensity fluctuations enables the measurement of a transition from exponential to Gaussian decay of the phase coherence of the polariton laser. It suggests large self-interaction energies in the polariton condensate, exceeding the laser bandwidth. Such strong interactions are unique to matter-wave lasers and important for nonlinear polariton devices. The results will guide future development of polariton lasers and nonlinear polariton devices.},
  language  = {en}
}
@article{RedlichLingnauHolzingeretal.2016,
  author    = {Redlich, Christoph and Lingnau, Benjamin and Holzinger, Steffen and Schlottmann, Elisabeth and Kreinberg, S{\"o}ren and Schneider, Christian and Kamp, Martin and H{\"o}fling, Sven and Wolters, Janik and Reitzenstein, Stephan and L{\"u}dge, Kathy},
  title     = {Mode-switching induced super-thermal bunching in quantum-dot microlasers},
  series = {New Journal of Physics},
  volume    = {18},
  journal   = {New Journal of Physics},
  number    = {063011},
  doi       = {10.1088/1367-2630/18/6/063011},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166286},
  year      = {2016},
  abstract  = {The super-thermal photon bunching in quantum-dot (QD) micropillar lasers is investigated both experimentally and theoretically via simulations driven by dynamic considerations. Using stochastic multi-mode rate equations we obtain very good agreement between experiment and theory in terms of intensity profiles and intensity-correlation properties of the examined QD micro-laser's emission. Further investigations of the time-dependent emission show that super-thermal photon bunching occurs due to irregular mode-switching events in the bimodal lasers. Our bifurcation analysis reveals that these switchings find their origin in an underlying bistability, such that spontaneous emission noise is able to effectively perturb the two competing modes in a small parameter region. We thus ascribe the observed high photon correlation to dynamical multistabilities rather than quantum mechanical correlations.},
  language  = {en}
}
@article{NitscheKimRoumposetal.2016,
  author    = {Nitsche, Wolfgang H. and Kim, Na Young and Roumpos, Georgios and Schneider, Christian and H{\"o}fling, Sven and Forchel, Alfred and Yamamoto, Yoshihisa},
  title     = {Spatial correlation of two-dimensional bosonic multimode condensates},
  series = {Physical Review A},
  volume    = {93},
  journal   = {Physical Review A},
  number    = {5},
  doi       = {10.1103/PhysRevA.93.053622},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188897},
  pages     = {53622},
  year      = {2016},
  abstract  = {The Berezinskii-Kosterlitz-Thouless (BKT) theorem predicts that two-dimensional bosonic condensates exhibit quasi-long-range order which is characterized by a slow decay of the spatial coherence. However previous measurements on exciton-polariton condensates revealed that their spatial coherence can decay faster than allowed under the BKT theory, and different theoretical explanations have already been proposed. Through theoretical and experimental study of exciton-polariton condensates, we show that the fast decay of the coherence can be explained through the simultaneous presence of multiple modes in the condensate.},
  language  = {en}
}
@article{LundtKlembtCherotchenkoetal.2016,
  author    = {Lundt, Nils and Klembt, Sebastian and Cherotchenko, Evgeniia and Betzold, Simon and Iff, Oliver and Nalitov, Anton V. and Klaas, Martin and Dietrich, Christof P. and Kavokin, Alexey V. and H{\"o}fling, Sven and Schneider, Christian},
  title     = {Room-temperature Tamm-plasmon exciton-polaritons with a WSe\(_{2}\) monolayer},
  series = {Nature Communications},
  volume    = {7},
  journal   = {Nature Communications},
  doi       = {10.1038/ncomms13328},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169470},
  year      = {2016},
  abstract  = {Solid-state cavity quantum electrodynamics is a rapidly advancing field, which explores the frontiers of light-matter coupling. Metal-based approaches are of particular interest in this field, as they carry the potential to squeeze optical modes to spaces significantly below the diffraction limit. Transition metal dichalcogenides are ideally suited as the active material in cavity quantum electrodynamics, as they interact strongly with light at the ultimate monolayer limit. Here, we implement a Tamm-plasmon-polariton structure and study the coupling to a monolayer of WSe\(_{2}\), hosting highly stable excitons. Exciton-polariton formation at room temperature is manifested in the characteristic energy-momentum dispersion relation studied in photoluminescence, featuring an anti-crossing between the exciton and photon modes with a Rabi-splitting of 23.5 meV. Creating polaritonic quasiparticles in monolithic, compact architectures with atomic monolayers under ambient conditions is a crucial step towards the exploration of nonlinearities, macroscopic coherence and advanced spinor physics with novel, low-mass bosons.},
  language  = {en}
}
@article{HeIffLundtetal.2016,
  author    = {He, Yu-Ming and Iff, Oliver and Lundt, Nils and Baumann, Vasilij and Davanco, Marcelo and Srinivasan, Kartik and H{\"o}fling, Sven and Schneider, Christian},
  title     = {Cascaded emission of single photons from the biexciton in monolayered WSe\(_{2}\)},
  series = {Nature Communications},
  volume    = {7},
  journal   = {Nature Communications},
  doi       = {10.1038/ncomms13409},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-169363},
  year      = {2016},
  abstract  = {Monolayers of transition metal dichalcogenide materials emerged as a new material class to study excitonic effects in solid state, as they benefit from enormous Coulomb correlations between electrons and holes. Especially in WSe\(_{2}\), sharp emission features have been observed at cryogenic temperatures, which act as single photon sources. Tight exciton localization has been assumed to induce an anharmonic excitation spectrum; however, the evidence of the hypothesis, namely the demonstration of a localized biexciton, is elusive. Here we unambiguously demonstrate the existence of a localized biexciton in a monolayer of WSe\(_{2}\), which triggers an emission cascade of single photons. The biexciton is identified by its time-resolved photoluminescence, superlinearity and distinct polarization in micro-photoluminescence experiments. We evidence the cascaded nature of the emission process in a cross-correlation experiment, which yields a strong bunching behaviour. Our work paves the way to a new generation of quantum optics experiments with two-dimensional semiconductors.},
  language  = {en}
}
@article{JahnkeGiesAssmannetal.2016,
  author    = {Jahnke, Frank and Gies, Christopher and Aßmann, Marc and Bayer, Manfred and Leymann, H.A.M. and Foerster, Alexander and Wiersig, Jan and Schneider, Christian and Kamp, Martin and H{\"o}fling, Sven},
  title     = {Giant photon bunching, superradiant pulse emission and excitation trapping in quantum-dot nanolasers},
  series = {Nature Communications},
  volume    = {7},
  journal   = {Nature Communications},
  number    = {11540},
  doi       = {10.1038/ncomms11540},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-166144},
  year      = {2016},
  abstract  = {Light is often characterized only by its classical properties, like intensity or coherence. When looking at its quantum properties, described by photon correlations, new information about the state of the matter generating the radiation can be revealed. In particular the difference between independent and entangled emitters, which is at the heart of quantum mechanics, can be made visible in the photon statistics of the emitted light. The well-studied phenomenon of superradiance occurs when quantum-mechanical correlations between the emitters are present. Notwithstanding, superradiance was previously demonstrated only in terms of classical light properties. Here, we provide the missing link between quantum correlations of the active material and photon correlations in the emitted radiation. We use the superradiance of quantum dots in a cavity-quantum electrodynamics laser to show a direct connection between superradiant pulse emission and distinctive changes in the photon correlation function. This directly demonstrates the importance of quantum-mechanical correlations and their transfer between carriers and photons in novel optoelectronic devices.},
  language  = {en}
}
@article{DietrichSteudeTropfetal.2016,
  author    = {Dietrich, Christof P. and Steude, Anja and Tropf, Laura and Schubert, Marcel and Kronenberg, Nils M. and Ostermann, Kai and H{\"o}fling, Sven and Gather, Malte C.},
  title     = {An exciton-polariton laser based on biologically produced fluorescent protein},
  series = {Science Advances},
  volume    = {2},
  journal   = {Science Advances},
  number    = {8},
  doi       = {10.1126/sciadv.1600666},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-171305},
  pages     = {e1600666},
  year      = {2016},
  abstract  = {Under adequate conditions, cavity polaritons form a macroscopic coherent quantum state, known as polariton condensate. Compared to Wannier-Mott excitons in inorganic semiconductors, the localized Frenkel excitons in organic emitter materials show weaker interaction with each other but stronger coupling to light, which recently enabled the first realization of a polariton condensate at room temperature. However, this required ultrafast optical pumping, which limits the applications of organic polariton condensates. We demonstrate room temperature polariton condensates of cavity polaritons in simple laminated microcavities filled with biologically produced enhanced green fluorescent protein (eGFP). The unique molecular structure of eGFP prevents exciton annihilation even at high excitation densities, thus facilitating polariton condensation under conventional nanosecond pumping. Condensation is clearly evidenced by a distinct threshold, an interaction-induced blueshift of the condensate, long-range coherence, and the presence of a second threshold at higher excitation density that is associated with the onset of photon lasing.},
  language  = {en}
}
@article{HorikiriYamaguchiKamideetal.2016,
  author    = {Horikiri, Tomoyuki and Yamaguchi, Makoto and Kamide, Kenji and Matsuo, Yasuhiro and Byrnes, Tim and Ishida, Natsuko and L{\"o}ffler, Andreas and H{\"o}fling, Sven and Shikano, Yutaka and Ogawa, Tetsuo and Forchel, Alfred and Yamamoto, Yoshihisa},
  title     = {High-energy side-peak emission of exciton-polariton condensates in high density regime},
  series = {Scientific Reports},
  volume    = {6},
  journal   = {Scientific Reports},
  number    = {25655},
  doi       = {10.1038/srep25655},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-167711},
  year      = {2016},
  abstract  = {In a standard semiconductor laser, electrons and holes recombine via stimulated emission to emit coherent light, in a process that is far from thermal equilibrium. Exciton-polariton condensates-sharing the same basic device structure as a semiconductor laser, consisting of quantum wells coupled to a microcavity-have been investigated primarily at densities far below the Mott density for signatures of Bose-Einstein condensation. At high densities approaching the Mott density, exciton-polariton condensates are generally thought to revert to a standard semiconductor laser, with the loss of strong coupling. Here, we report the observation of a photoluminescence sideband at high densities that cannot be accounted for by conventional semiconductor lasing. This also differs from an upper-polariton peak by the observation of the excitation power dependence in the peak-energy separation. Our interpretation as a persistent coherent electron-hole-photon coupling captures several features of this sideband, although a complete understanding of the experimental data is lacking. A full understanding of the observations should lead to a development in non-equilibrium many-body physics.},
  language  = {en}
}
@article{WurdackLundtKlaasetal.2017,
  author    = {Wurdack, Matthias and Lundt, Nils and Klaas, Martin and Baumann, Vasilij and Kavokin, Alexey V. and H{\"o}fling, Sven and Schneider, Christian},
  title     = {Observation of hybrid Tamm-plasmon exciton-polaritons with GaAs quantum wells and a MoSe\(_{2}\) monolayer},
  series = {Nature Communications},
  volume    = {8},
  journal   = {Nature Communications},
  number    = {259},
  doi       = {10.1038/s41467-017-00155-w},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170480},
  year      = {2017},
  abstract  = {Strong light matter coupling between excitons and microcavity photons, as described in the framework of cavity quantum electrodynamics, leads to the hybridization of light and matter excitations. The regime of collective strong coupling arises, when various excitations from different host media are strongly coupled to the same optical resonance. This leads to a well-controllable admixture of various matter components in three hybrid polariton modes. Here, we study a cavity device with four embedded GaAs quantum wells hosting excitons that are spectrally matched to the A-valley exciton resonance of a MoSe\(_{2}\) monolayer. The formation of hybrid polariton modes is evidenced in momentum resolved photoluminescence and reflectivity studies. We describe the energy and k-vector distribution of exciton-polaritons along the hybrid modes by a thermodynamic model, which yields a very good agreement with the experiment.},
  language  = {en}
}
@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}
}