A5005429676- Quantum Information and Cryptography
- Quantum Mechanics and Applications
- Orbital Angular Momentum in Optics
- Quantum optics and atomic interactions
- Photonic and Optical Devices
- Quantum Computing Algorithms and Architecture
- Neural Networks and Reservoir Computing
- Random lasers and scattering media
- Advanced Optical Sensing Technologies
- Advanced Fiber Laser Technologies
- Digital Holography and Microscopy
- Mechanical and Optical Resonators
- Advanced Fluorescence Microscopy Techniques
- Laser-Matter Interactions and Applications
- Atomic and Subatomic Physics Research
- Photorefractive and Nonlinear Optics
- Optical Network Technologies
- Optical Coherence Tomography Applications
- Molecular Communication and Nanonetworks
- Advanced Optical Imaging Technologies
- Optical Wireless Communication Technologies
- Spacecraft Design and Technology
- Advanced Thermodynamics and Statistical Mechanics
- Chaos-based Image/Signal Encryption
- Philosophy and History of Science
Friedrich Schiller University Jena
2019-2024
Fraunhofer Institute for Applied Optics and Precision Engineering
2019-2024
Albert Einstein College of Medicine
2022-2023
Leibniz Institute of Photonic Technology
2022
Austrian Academy of Sciences
2015-2019
Institute for Quantum Optics and Quantum Information Innsbruck
2015-2019
Vienna Center for Quantum Science and Technology
2018-2019
University of Vienna
2018-2019
Institute of Photonic Sciences
2011-2016
Local realism is the worldview in which physical properties of objects exist independently measurement and where influences cannot travel faster than speed light. Bell's theorem states that this incompatible with predictions quantum mechanics, as expressed inequalities. Previous experiments convincingly supported predictions. Yet, every experiment requires assumptions provide loopholes for a local realist explanation. Here, we report Bell test closes most significant these simultaneously....
Tests of the predictions quantum mechanics for entangled systems have provided increasing evidence against local realistic theories. However, there remains crucial challenge simultaneously closing all major loopholes—the locality, freedom-of-choice and detection loopholes—in a single experiment. An important sub-class theories can be tested with concept 'steering'. The term 'steering' was introduced by Schrödinger in 1935 fact that entanglement would seem to allow an experimenter remotely...
Noise can be considered the natural enemy of quantum information. An often implied benefit high-dimensional entanglement is its increased resilience to noise. However, manifesting this potential in an experimentally meaningful fashion challenging and has never been done before. In infinite dimensional spaces, discretisation inevitable renders effective dimension states a tunable parameter. Owing advances experimental techniques theoretical tools, we demonstrate resistance noise by...
Bell's theorem states that some predictions of quantum mechanics cannot be reproduced by a local-realist theory. That conflict is expressed inequality, which usually derived under the assumption there are no statistical correlations between choices measurement settings and anything else can causally affect outcomes. In previous experiments, this "freedom choice" was addressed ensuring selection via conventional "quantum random number generators" spacelike separated from entangled particle...
In this Letter, we present a cosmic Bell experiment with polarization-entangled photons, in which measurement settings were determined based on real-time measurements of the wavelength photons from high-redshift quasars, whose light was emitted billions years ago; simultaneously ensures locality. Assuming fair sampling for all detected and that quasar had not been selectively altered or previewed between emission detection, observe statistically significant violation Bell's inequality by 9.3...
Quantum entanglement is a fundamental resource in quantum information processing and its distribution between distant parties key challenge communications. Increasing the dimensionality of has been shown to improve robustness channel capacities secure Here we report on genuine high-dimensional via 1.2-km-long free-space link across Vienna. We exploit hyperentanglement, that is, simultaneous polarization energy-time bases, encode information, observe high-visibility interference for...
Abstract Quantum imaging is a multifaceted field of research that promises highly efficient in extreme spectral ranges as well ultralow‐light microscopy. Since the first proof‐of‐concept experiments over 30 years ago, has evolved from fascinating academic to verge demonstrating practical technological enhancements and Here, aim give researchers outside quantum optical community, particular those applying technology, an overview several promising approaches evaluate both benefit prospects for...
Significance Entanglement, the existence of correlations in distant systems stronger than those allowed by classical physics, is one most astonishing features quantum physics. By distributing entangled photon pairs over a 96-km-long submarine fiber, which part existing infrastructure carrying internet traffic, we demonstrate that polarization entanglement-based key distribution (QKD) can be implemented real-world scenarios. QKD facilitates secure communication links between two parties,...
Entangled photon-pairs are a critical resource in quantum communication protocols ranging from key distribution to teleportation. The current workhorse technique for producing is via spontaneous parametric down conversion (SPDC) bulk nonlinear crystals. increased prominence of networks has led growing interest deployable high performance entangled photon-pair sources. This manuscript provides review the state-of-the-art bulk-optics-based SPDC sources with continuous wave pump, and discusses...
Holography exploits the interference of light fields to obtain a systematic reconstruction wavefronts. Classical holography techniques have been very successful in diverse areas such as microscopy, manufacturing technology, and basic science. Extending holographic methods level single photons has proven challenging, since applying classical this regime pose technical problems. Recently retrieval spatial structure photon, using another photon under experimental control with well-characterized...
Event synchronization is a ubiquitous task, with applications ranging from 5G technology to industrial automation and smart power grids. The emergence of quantum communication networks will further increase the demand for precise in optical electronic domains, which implies significant resource overhead, such as requirement ultrastable clocks or additional lasers. Here, we show how temporal correlations photons may be harnessed networks. We achieve stable jitter $<68$ ps few 44 correlated...
Random numbers are essential for applications ranging from secure communications to numerical simulation and quantitative finance. Algorithms can rapidly produce pseudo-random outcomes, series of that mimic most properties true random while quantum number generators (QRNGs) exploit intrinsic randomness numbers. Single-photon QRNGs conceptually simple but few bits per detection. In contrast, vacuum fluctuations a vast resource QRNGs: they broad-band thus encode many second. Direct recording...
Ultrabright sources of entangled photon pairs with high heralding efficiency are an important step in the pursuit high-bit-rate entanglement-base quantum key distribution, as well enabling tool for loss-sensitive optics experiments. Here, we present a robust single-mode fiber-coupled source polarization-entangled photons around 810 nm both brightness and efficiency. Our approach is based on quasi-phase-matched spontaneous parametric downconversion (SPDC) from periodically poled KTiOPO4...
Abstract Quantum key distribution (QKD) is a pioneering quantum technology on the brink of widespread deployment. Nevertheless, secret keys beyond few 100 km at practical rates remains major challenge. One approach to circumvent lossy terrestrial transmission entangled photon pairs deployment optical satellite links. Optimizing these non-static links yield highest possible rate essential for their successful operation. We therefore developed high-brightness polarization-entangled pair source...
Abstract Imaging and microscopy are some of the most important tools in modern life science for getting new insights into metabolisms or unravelling bio‐chemical processes. However, particular low‐light observations outside visible spectrum still challenging a limiting factor. A rugged, label‐free quantum imaging system is presented capable recording at video rate regime, while illuminating sample with undetected light different wavelength. The results pave way field deployable device...
We present a simple but highly efficient source of polarization-entangled photons based on spontaneous parametric down-conversion (SPDC) in bulk periodically poled potassium titanyl phosphate crystals (PPKTP) pumped by 405 nm laser diode. Utilizing one the highest available nonlinear coefficients non-degenerate, collinear type-0 phase-matching configuration, we generate polarization entanglement via crossed-crystal scheme and detect 0.64 million photon pair events/s/mW, while maintaining an...
Quantum techniques can be used to enhance the signal-to-noise ratio in optical imaging. Leveraging latest advances single-photon avalanche diode array cameras and multiphoton detection techniques, here, we introduce a supersensitive phase imager, which uses space-polarization hyperentanglement operate over large field of view without need scanning operation. We show quantum-enhanced imaging birefringent nonbirefringent samples areas, with sensitivity improvements equivalent classical...
Abstract Information exchange between two distant parties, where information is shared without physically transporting it, a crucial resource in future quantum networks. Doing so with high-dimensional states offers the promise of higher capacity and improved resilience to noise, but progress date has been limited. Here we demonstrate how nonlinear parametric process allows for arbitrary state projections spatial degree freedom, strong coherent field enhances probability process. This us...
Sources of entanglement are an enabling resource in quantum technology, and pushing the limits generation rate quality is a necessary pre-requisite towards practical applications. Here, we present ultra-bright source polarization-entangled photon pairs based on time-reversed Hong-Ou-Mandel interference. By superimposing four pair-creation possibilities polarization beam splitter, identical photons separated into two spatial modes without usual requirement for wavelength distinguishability or...
High-dimensional quantum entanglement is currently one of the most prolific fields in information processing due to its high capacity and error resilience. A versatile method for harnessing high-dimensional has long been hailed as an absolute necessity exploration science technologies. Here we exploit Hong-Ou-Mandel interference manipulate discrete frequency arbitrary-dimensional Hilbert space. The generation characterization two-, four- six-dimensional entangled qudits are theoretically...
We present a polarization-entangled photon pair source operating in the visible light range around 532 nm. Employing collinear crossed-crystal scheme with type-I degenerate phase matching barium borate (BBO), our achieves brightness of 9.5 k pairs/s/mW and quantum state fidelity 98.3%, making it candidate for integration microscopes make use advantages mid-visible optimized single-photon detection technologies. In order to study potential applications, we trade-off between polarization...
Abstract Quantum communication has seen rapid progress towards practical large-scale networks, with quantum key distribution (QKD) spearheading this development. While fibre-based systems have been shown to be well suited for metropolitan scales, suitable fibre infrastructure may not always in place. Here, we make the case an entanglement-based free-space network as a and efficient alternative applications. We developed deployable QKD system demonstrated its use realistic scenarios. For...
Optical clock networks connected by phase-coherent links offer significant potential for advancing fundamental research and diverse scientific applications. Free-space optical frequency transfer extends fiber-based connectivity to remote areas holds the global coverage via satellite links. Here we present a compact robust portable, rack-integrated two-way free-space link characterization system. Equipped with plug-and-play capabilities, system enables straightforward interfacing various...