Refine
Has Fulltext
- yes (26)
Is part of the Bibliography
- yes (26)
Year of publication
Document Type
- Journal article (26)
Language
- English (26)
Keywords
- quantum dots (4)
- emission (2)
- generation (2)
- interband cascade lasers (2)
- metamorphic buffer layer (2)
- photon statistics (2)
- quantum dot (2)
- quantum physics (2)
- resonant tunneling diode (2)
- strong coupling (2)
- two-dimensional materials (2)
- 1550 nm (1)
- Bistability (1)
- EDX spectra (1)
- Exciton-polariton condensate (1)
- FTIR spectroscopy (1)
- GaAs (1)
- Generation (1)
- III–V semiconductor devices (1)
- LED (1)
- Long-range order (1)
- Microcavity (1)
- Microcavity devices (1)
- Nonlinear Dynamics (1)
- Physics (1)
- QKD (1)
- QW interface profile (1)
- Quantum-well, -wire and -dot devices (1)
- Regimes (1)
- Resonators (1)
- Scattering (1)
- Subject (1)
- Systems (1)
- Vcsels (1)
- Vortices (1)
- atom (1)
- band structure (1)
- cavity device (1)
- cavity polaritons (1)
- coherent light (1)
- coherent multidimensional spectroscopy (1)
- color centers (1)
- communication (1)
- condensed matter physics (1)
- correlation properties (1)
- crystal (1)
- downconversion (1)
- droplet epitaxy (1)
- electrically driven (1)
- electronic properties and materials (1)
- enhanced green fluorescent protein (1)
- exciton (1)
- exciton-polariton condensates (1)
- excitons (1)
- fourier transform spectroscopy (1)
- free space (1)
- heralded entanglement (1)
- interface (1)
- intermixing (1)
- laser spectroscopy (1)
- lasers (1)
- light sources (1)
- micro-photoluminescence (1)
- microlaser (1)
- microresonators (1)
- mid-infrared (1)
- mid-infrared sensing (1)
- mode (1)
- molecular beam epitaxy (1)
- nanoactivity (1)
- nanophotonics and plasmonics (1)
- nanowire (1)
- noise and multimode dynamics (1)
- nonlinear dynamics (1)
- optics and photonics (1)
- photoluminescence (1)
- photon bunching (1)
- photon counting (1)
- photon lasing (1)
- photonics (1)
- photoreflectance (1)
- photosensor (1)
- polarition condensate (1)
- polariton laser (1)
- quantized vortices (1)
- quantum communication (1)
- quantum communications (1)
- quantum dot laser (1)
- quantum key distribution (1)
- quantum mechanics (1)
- quantum repeaters (1)
- quantum-well -wire and -dot devices (1)
- resonators (1)
- room temperature (1)
- semiconductor microavity (1)
- semiconductor quantum dots (1)
- side-peak emission (1)
- single photon (1)
- single-photon detectors (1)
- single-photon source (1)
- spatially resolved photoluminescence (1)
- standard semiconductor laser (1)
- stimulated (1)
- superradiant pulse emission (1)
- tapers (1)
- telecommunication spectral range (1)
- time (1)
- transition metal dichalcogenide (1)
- trapped atoms/ions (1)
- type II GaIn(As)Sb/GaSb (1)
- type II quantum wells (1)
- up-conversion (1)
Institute
- Physikalisches Institut (26) (remove)
Sonstige beteiligte Institutionen
- Wilhelm-Conrad-Röntgen-Forschungszentrum für komplexe Materialsysteme (3)
- Arizona State University, Tempe, Arizona, USA (1)
- Fraunhofer-Institute for Applied Optics and Precision Engineering IOF Jena, Germany (1)
- Friedrich Schiller University Jena, Germany (1)
- Max Planck School of Photonics Jena, Germany (1)
- National Institute for Materials Science, Tsukuba, Japan (1)
- Röntgen Center for Complex Material Systems (RCCM), Am Hubland, 97074 W¨urzburg, Germany (1)
- University of Oldenburg, Germany (1)
- University of Science and Technology of China, Hefei, China (1)
- Wilhelm Conrad Röntgen-Center for Complex Material Systems, Würzburg (1)
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.
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.
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.
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.
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
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.
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.
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.
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.
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.