TY - JOUR A1 - Wyborski, Paweł A1 - Podemski, Paweł A1 - Wroński, Piotr Andrzej A1 - Jabeen, Fauzia A1 - Höfling, Sven A1 - Sęk, Grzegorz T1 - Electronic and optical properties of InAs QDs grown by MBE on InGaAs metamorphic buffer JF - Materials N2 - We present the optical characterization of GaAs-based InAs quantum dots (QDs) grown by molecular beam epitaxy on a digitally alloyed InGaAs metamorphic buffer layer (MBL) with gradual composition ensuring a redshift of the QD emission up to the second telecom window. Based on the photoluminescence (PL) measurements and numerical calculations, we analyzed the factors influencing the energies of optical transitions in QDs, among which the QD height seems to be dominating. In addition, polarization anisotropy of the QD emission was observed, which is a fingerprint of significant valence states mixing enhanced by the QD confinement potential asymmetry, driven by the decreased strain with increasing In content in the MBL. The barrier-related transitions were probed by photoreflectance, which combined with photoluminescence data and the PL temperature dependence, allowed for the determination of the carrier activation energies and the main channels of carrier loss, identified as the carrier escape to the MBL barrier. Eventually, the zero-dimensional character of the emission was confirmed by detecting the photoluminescence from single QDs with identified features of the confined neutral exciton and biexciton complexes via the excitation power and polarization dependences. KW - molecular beam epitaxy KW - quantum dot KW - metamorphic buffer layer KW - band structure KW - photoluminescence KW - photoreflectance Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-297037 SN - 1996-1944 VL - 15 IS - 3 ER - TY - JOUR A1 - Pfenning, Andreas A1 - Krüger, Sebastian A1 - Jabeen, Fauzia A1 - Worschech, Lukas A1 - Hartmann, Fabian A1 - Höfling, Sven T1 - Single-photon counting with semiconductor resonant tunneling devices JF - Nanomaterials N2 - Optical quantum information science and technologies require the capability to generate, control, and detect single or multiple quanta of light. The need to detect individual photons has motivated the development of a variety of novel and refined single-photon detectors (SPDs) with enhanced detector performance. Superconducting nanowire single-photon detectors (SNSPDs) and single-photon avalanche diodes (SPADs) are the top-performer in this field, but alternative promising and innovative devices are emerging. In this review article, we discuss the current state-of-the-art of one such alternative device capable of single-photon counting: the resonant tunneling diode (RTD) single-photon detector. Due to their peculiar photodetection mechanism and current-voltage characteristic with a region of negative differential conductance, RTD single-photon detectors provide, theoretically, several advantages over conventional SPDs, such as an inherently deadtime-free photon-number resolution at elevated temperatures, while offering low dark counts, a low timing jitter, and multiple photon detection modes. This review article brings together our previous studies and current experimental results. We focus on the current limitations of RTD-SPDs and provide detailed design and parameter variations to be potentially employed in next-generation RTD-SPD to improve the figure of merits of these alternative single-photon counting devices. The single-photon detection capability of RTDs without quantum dots is shown. KW - single-photon detectors KW - resonant tunneling diode KW - photon counting KW - III–V semiconductor devices Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-281922 SN - 2079-4991 VL - 12 IS - 14 ER - TY - JOUR A1 - Rothmayr, Florian A1 - Guarin Castro, Edgar David A1 - Hartmann, Fabian A1 - Knebl, Georg A1 - Schade, Anne A1 - Höfling, Sven A1 - Koeth, Johannes A1 - Pfenning, Andreas A1 - Worschech, Lukas A1 - Lopez-Richard, Victor T1 - Resonant tunneling diodes: mid-infrared sensing at room temperature JF - Nanomaterials N2 - Resonant tunneling diode photodetectors appear to be promising architectures with a simple design for mid-infrared sensing operations at room temperature. We fabricated resonant tunneling devices with GaInAsSb absorbers that allow operation in the 2–4 μm range with significant electrical responsivity of 0.97 A/W at 2004 nm to optical readout. This paper characterizes the photosensor response contrasting different operational regimes and offering a comprehensive theoretical analysis of the main physical ingredients that rule the sensor functionalities and affect its performance. We demonstrate how the drift, accumulation, and escape efficiencies of photogenerated carriers influence the electrostatic modulation of the sensor's electrical response and how they allow controlling the device's sensing abilities. KW - resonant tunneling diode KW - mid-infrared sensing KW - photosensor Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-267152 SN - 2079-4991 VL - 12 IS - 6 ER - TY - JOUR A1 - Li, Donghai A1 - Shan, Hangyong A1 - Rupprecht, Christoph A1 - Knopf, Heiko A1 - Watanabe, Kenji A1 - Taniguchi, Takashi A1 - Qin, Ying A1 - Tongay, Sefaattin A1 - Nuß, Matthias A1 - Schröder, Sven A1 - Eilenberger, Falk A1 - Höfling, Sven A1 - Schneider, Christian A1 - Brixner, Tobias T1 - Hybridized exciton-photon-phonon states in a transition-metal-dichalcogenide van-der-Waals heterostructure microcavity JF - Physical Review Letters N2 - Excitons in atomically thin transition-metal dichalcogenides (TMDs) have been established as an attractive platform to explore polaritonic physics, owing to their enormous binding energies and giant oscillator strength. Basic spectral features of exciton polaritons in TMD microcavities, thus far, were conventionally explained via two-coupled-oscillator models. This ignores, however, the impact of phonons on the polariton energy structure. Here we establish and quantify the threefold coupling between excitons, cavity photons, and phonons. For this purpose, we employ energy-momentum-resolved photoluminescence and spatially resolved coherent two-dimensional spectroscopy to investigate the spectral properties of a high-quality-factor microcavity with an embedded WSe\(_2\) van-der-Waals heterostructure at room temperature. Our approach reveals a rich multi-branch structure which thus far has not been captured in previous experiments. Simulation of the data reveals hybridized exciton-photon-phonon states, providing new physical insight into the exciton polariton system based on layered TMDs. KW - strong coupling KW - laser spectroscopy KW - transition metal dichalcogenide KW - coherent multidimensional spectroscopy KW - exciton Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-351303 UR - https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.087401 SN - 1079-7114 ET - accepted version ER - TY - JOUR A1 - Wroński, Piotr Andrzej A1 - Wyborski, Paweł A1 - Musiał, Anna A1 - Podemski, Paweł A1 - Sęk, Grzegorz A1 - Höfling, Sven A1 - Jabeen, Fauzia T1 - Metamorphic Buffer Layer Platform for 1550 nm Single-Photon Sources Grown by MBE on (100) GaAs Substrate JF - Materials N2 - We demonstrate single-photon emission with a low probability of multiphoton events of 5% in the C-band of telecommunication spectral range of standard silica fibers from molecular beam epitaxy grown (100)-GaAs-based structure with InAs quantum dots (QDs) on a metamorphic buffer layer. For this purpose, we propose and implement graded In content digitally alloyed InGaAs metamorphic buffer layer with maximal In content of 42% and GaAs/AlAs distributed Bragg reflector underneath to enhance the extraction efficiency of QD emission. The fundamental limit of the emission rate for the investigated structures is 0.5 GHz based on an emission lifetime of 1.95 ns determined from time-resolved photoluminescence. We prove the relevance of a proposed technology platform for the realization of non-classical light sources in the context of fiber-based quantum communication applications. KW - single-photon source KW - quantum dots KW - telecommunication spectral range KW - metamorphic buffer layer Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246145 SN - 1996-1944 VL - 14 IS - 18 ER - TY - JOUR A1 - van Loock, Peter A1 - Alt, Wolfgang A1 - Becher, Christoph A1 - Benson, Oliver A1 - Boche, Holger A1 - Deppe, Christian A1 - Eschner, Jürgen A1 - Höfling, Sven A1 - Meschede, Dieter A1 - Michler, Peter A1 - Schmidt, Frank A1 - Weinfurter, Harald T1 - Extending Quantum Links: Modules for Fiber‐ and Memory‐Based Quantum Repeaters JF - Advanced Quantum Technologies N2 - Elementary building blocks for quantum repeaters based on fiber channels and memory stations are analyzed. Implementations are considered for three different physical platforms, for which suitable components are available: quantum dots, trapped atoms and ions, and color centers in diamond. The performances of basic quantum repeater links for these platforms are evaluated and compared, both for present‐day, state‐of‐the‐art experimental parameters as well as for parameters that can in principle be reached in the future. The ultimate goal is to experimentally explore regimes at intermediate distances—up to a few 100 km—in which the repeater‐assisted secret key transmission rates exceed the maximal rate achievable via direct transmission. Two different protocols are considered, one of which is better adapted to the higher source clock rate and lower memory coherence time of the quantum dot platform, while the other circumvents the need of writing photonic quantum states into the memories in a heralded, nondestructive fashion. The elementary building blocks and protocols can be connected in a modular form to construct a quantum repeater system that is potentially scalable to large distances. KW - color centers KW - quantum communication KW - quantum dots KW - quantum repeaters KW - trapped atoms/ions Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228322 VL - 3 IS - 11 ER - TY - JOUR A1 - Schlottmann, Elisabeth A1 - Schicke, David A1 - Krüger, Felix A1 - Lingnau, Benjamin A1 - Schneider, Christian A1 - Höfling, Sven A1 - Lüdge, Kathy A1 - Porte, Xavier A1 - Reitzenstein, Stephan T1 - Stochastic polarization switching induced by optical injection in bimodal quantum-dot micropillar lasers JF - Optics Express N2 - 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 KW - Nonlinear Dynamics KW - Bistability KW - Generation KW - Subject KW - Regimes KW - Physics KW - Vcsels Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228603 VL - 27 IS - 20 ER - TY - JOUR A1 - Wurdack, Matthias A1 - Lundt, Nils A1 - Klaas, Martin A1 - Baumann, Vasilij A1 - Kavokin, Alexey V. A1 - Höfling, Sven A1 - Schneider, Christian T1 - Observation of hybrid Tamm-plasmon exciton-polaritons with GaAs quantum wells and a MoSe\(_{2}\) monolayer JF - Nature Communications N2 - 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. KW - two-dimensional materials KW - microresonators KW - nanophotonics and plasmonics KW - cavity device KW - strong coupling Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170480 VL - 8 IS - 259 ER - TY - JOUR A1 - Kim, Seonghoon A1 - Zhang, Bo A1 - Wang, Zhaorong A1 - Fischer, Julian A1 - Brodbeck, Sebastian A1 - Kamp, Martin A1 - Schneider, Christian A1 - Höfling, Sven A1 - Deng, Hui T1 - Coherent Polariton Laser JF - Physical Review X N2 - 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. KW - polariton laser KW - condensed matter physics KW - photonics KW - quantum physics KW - coherent light Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166597 VL - 6 IS - 011026 ER - TY - JOUR A1 - Redlich, Christoph A1 - Lingnau, Benjamin A1 - Holzinger, Steffen A1 - Schlottmann, Elisabeth A1 - Kreinberg, Sören A1 - Schneider, Christian A1 - Kamp, Martin A1 - Höfling, Sven A1 - Wolters, Janik A1 - Reitzenstein, Stephan A1 - Lüdge, Kathy T1 - Mode-switching induced super-thermal bunching in quantum-dot microlasers JF - New Journal of Physics N2 - 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. KW - microlaser KW - nonlinear dynamics KW - correlation properties KW - photon statistics KW - noise and multimode dynamics KW - quantum dot laser Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166286 VL - 18 IS - 063011 ER -