Author
Stephan Reitzenstein
Other affiliations: Conrad Hotels, University of Würzburg
Bio: Stephan Reitzenstein is an academic researcher from Technical University of Berlin. The author has contributed to research in topics: Quantum dot & Photon. The author has an hindex of 51, co-authored 406 publications receiving 11384 citations. Previous affiliations of Stephan Reitzenstein include Conrad Hotels & University of Würzburg.
Papers published on a yearly basis
Papers
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TL;DR: The observation of strong coupling of a single two-level solid-state system with a photon, as realized by a single quantum dot in a semiconductor microcavity, may provide a basis for future applications in quantum information processing or schemes for coherent control.
Abstract: Cavity quantum electrodynamics, a central research field in optics and solid-state physics, addresses properties of atom-like emitters in cavities and can be divided into a weak and a strong coupling regime. For weak coupling, the spontaneous emission can be enhanced or reduced compared with its vacuum level by tuning discrete cavity modes in and out of resonance with the emitter. However, the most striking change of emission properties occurs when the conditions for strong coupling are fulfilled. In this case there is a change from the usual irreversible spontaneous emission to a reversible exchange of energy between the emitter and the cavity mode. This coherent coupling may provide a basis for future applications in quantum information processing or schemes for coherent control. Until now, strong coupling of individual two-level systems has been observed only for atoms in large cavities. Here we report the observation of strong coupling of a single two-level solid-state system with a photon, as realized by a single quantum dot in a semiconductor microcavity. The strong coupling is manifest in photoluminescence data that display anti-crossings between the quantum dot exciton and cavity-mode dispersion relations, characterized by a vacuum Rabi splitting of about 140 microeV.
1,809 citations
12 Nov 2015
TL;DR: An electrically pumped polariton laser based on a microcavity containing multiple quantum wells is presented, which can be extended to room-temperature operation using wide-bandgap materials and proves polariton Laser emission unambiguously.
Abstract: Exciton-polaritons are bosonic quasi-particles originating in the strong coupling regime. They can undergo a condensation process leading to coherent emission. We show a realisation of electrically driven polariton condensates using a p-i-n doped microcavity.
390 citations
TL;DR: This work presents proof that the emission from a strongly-coupled QD- microcavity system is dominated by a single quantum emitter.
Abstract: We observe antibunching in the photons emitted from a strongly coupled single quantum dot and pillar microcavity in resonance. When the quantum dot was spectrally detuned from the cavity mode, the cavity emission remained antibunched, and also anticorrelated from the quantum dot emission. Resonant pumping of the selected quantum dot via an excited state enabled these observations by eliminating the background emitters that are usually coupled to the cavity. This device demonstrates an on-demand single-photon source operating in the strong coupling regime, with a Purcell factor of 61+/-7 and quantum efficiency of 97%.
334 citations
09 Feb 2006
TL;DR: In this article, a planar cavity quantum electrodynamics (cQED) system based on a low density In0.3Ga 0.7As quantum layer placed as the active layer in a high quality planar AlAs/GaAs distributed Bragg reflector cavity grown by molecular beam epitaxy is described.
Abstract: Properties of atom-like emitters in cavities are successfully described by cavity quantum electrodynamics (cQED). We
report on cavity quantum electrodynamics (cQED) experiments in a single quantum dot semiconductor system. CQED,
which is a very active research field in optics and solid state physics, can be divided into a weak and a strong coupling
regime. In case of weak coupling, the spontaneous emission rate of an atom-like emitter, e.g. a single quantum dot
exciton, can be enhanced or reduced compared to the value in vacuum in an irreversible emission process. In contrast, a
reversible energy exchange between the emitter and the cavity mode takes place when the conditions for strong coupling
are fulfilled. We investigate weak as well as strong coupling in a system based on a low density In0.3Ga 0.7As quantum
dot layer placed as the active layer in a high quality planar AlAs/GaAs distributed Bragg reflector cavity grown by
molecular beam epitaxy. Using electron beam lithography and deep plasma etching, micropillars with high Q-factors
(up to 43.000 for 4 μm diameter) were realized from the planar cavity structure. Due to the high oscillator strength of
the In0.3Ga 0.7As quantum dots together with a small mode volume in high finesse micropillar cavities it is possible to
observe strong coupling characterized by a vacuum Rabi splitting of 140 μeV. The fabrication of high-Q micropillar
cavities as well as conditions necessary to realize strong coupling in the present system are discussed in detail.
321 citations
TL;DR: In this paper, the authors report on AlAs∕GaAs micropillar cavities with unprecedented quality factors based on high reflectivity distributed Bragg reflectors (DBRs).
Abstract: The authors report on AlAs∕GaAs micropillar cavities with unprecedented quality factors based on high reflectivity distributed Bragg reflectors (DBRs). Due to an increased number of mirror pairs in the DBRs and an optimized etching process record quality (Q) factors up to 165.000 are observed for micropillars with diameters of 4μm. Optical studies reveal a very small ellipticity of 5×10−4 of the pillar cross section. Because of the high Q factors, strong coupling with a vacuum Rabi splitting of 23μeV is observed for micropillars with a diameter of 3μm.
290 citations
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TL;DR: In this paper, the authors describe photonic crystals as the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures, and the interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.
Abstract: The term photonic crystals appears because of the analogy between electron waves in crystals and the light waves in artificial periodic dielectric structures. During the recent years the investigation of one-, two-and three-dimensional periodic structures has attracted a widespread attention of the world optics community because of great potentiality of such structures in advanced applied optical fields. The interest in periodic structures has been stimulated by the fast development of semiconductor technology that now allows the fabrication of artificial structures, whose period is comparable with the wavelength of light in the visible and infrared ranges.
2,722 citations
TL;DR: In this paper, the electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin- and valley-dependent properties are reviewed.
Abstract: The electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin- and valley-dependent properties are reviewed. Recent advances in the development of atomically thin layers of van der Waals bonded solids have opened up new possibilities for the exploration of 2D physics as well as for materials for applications. Among them, semiconductor transition metal dichalcogenides, MX2 (M = Mo, W; X = S, Se), have bandgaps in the near-infrared to the visible region, in contrast to the zero bandgap of graphene. In the monolayer limit, these materials have been shown to possess direct bandgaps, a property well suited for photonics and optoelectronics applications. Here, we review the electronic and optical properties and the recent progress in applications of 2D semiconductor transition metal dichalcogenides with emphasis on strong excitonic effects, and spin- and valley-dependent properties.
2,612 citations
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TL;DR: A number of physical systems, spanning much of modern physics, are being developed for this task, ranging from single particles of light to superconducting circuits, and it is not yet clear which, if any, will ultimately prove successful as discussed by the authors.
Abstract: Quantum mechanics---the theory describing the fundamental workings of nature---is famously counterintuitive: it predicts that a particle can be in two places at the same time, and that two remote particles can be inextricably and instantaneously linked These predictions have been the topic of intense metaphysical debate ever since the theory's inception early last century However, supreme predictive power combined with direct experimental observation of some of these unusual phenomena leave little doubt as to its fundamental correctness In fact, without quantum mechanics we could not explain the workings of a laser, nor indeed how a fridge magnet operates Over the last several decades quantum information science has emerged to seek answers to the question: can we gain some advantage by storing, transmitting and processing information encoded in systems that exhibit these unique quantum properties? Today it is understood that the answer is yes Many research groups around the world are working towards one of the most ambitious goals humankind has ever embarked upon: a quantum computer that promises to exponentially improve computational power for particular tasks A number of physical systems, spanning much of modern physics, are being developed for this task---ranging from single particles of light to superconducting circuits---and it is not yet clear which, if any, will ultimately prove successful Here we describe the latest developments for each of the leading approaches and explain what the major challenges are for the future
2,301 citations
TL;DR: The first quantum technology that harnesses quantum mechanical effects for its core operation has arrived in the form of commercially available quantum key distribution systems as mentioned in this paper, which achieves enhanced security by encoding information in photons such that an eavesdropper in the system can be detected.
Abstract: The first quantum technology that harnesses quantum mechanical effects for its core operation has arrived in the form of commercially available quantum key distribution systems. This technology achieves enhanced security by encoding information in photons such that an eavesdropper in the system can be detected. Anticipated future quantum technologies include large-scale secure networks, enhanced measurement and lithography, and quantum information processors, which promise exponentially greater computational power for particular tasks. Photonics is destined to have a central role in such technologies owing to the high-speed transmission and outstanding low-noise properties of photons. These technologies may use single photons, quantum states of bright laser beams or both, and will undoubtedly apply and drive state-of-the-art developments in photonics.
1,889 citations