Physicists of the group of Prof. Harald Weinfurter (at the Ludwig-Maximilians-Universität München and the Max-Planck-Institute for Quantum Optics, Garching, Germany, in the Cluster of Excellence "Munich Center for Advanced Photonics") succeeded in developing a new method for the generation of intense, ultra-short light pulses in the ultraviolet (UV) wavelength region at high repetition rates. These pulses are essential for the generation of multiple entangled photons.
The goal of the Munich scientists is to entangle as many photons as possible and to study their properties. Entanglement, or Einstein's "spooky action at a distance", still fascinates quantum physicists today. Therefore, their focus is not only on realizing the quantum computer, but they would also like to obtain a deeper insight into the world of quantum physics and to understand how entanglement is distributed over large quantum systems. To generate several entangled photons at once, ultra-short stroboscope-like light pulses of very high power are required. The main challenge for this project was to obtain ultra-short, high energy pulses with a high repetition rate and at UV wavelengths. All these demands had to be fulfilled at the same time.
The Munich team has now succeeded in transferring a method working in the infrared wavelength region to the more powerful ultraviolet region. They implemented a resonator to enhance UV light pulses with a pulse duration in the femtosecond regime (10-15 seconds) at a high repetition rate (82 MHz). Inside the resonator the pulses continuously add up only if the following condition is fulfilled: each incoming pulse has to overlap exactly with the pulses already stored in the resonator. The light intensity created in the resonator exceeds those of comparable commercial laser systems by at least a factor of five. A crystal inside the resonator then allows the generation of entangled photons.
Roland Krischek, who co-constructed and characterized the light resonator, sees a lot of potential: "This light resonator allows us to study entanglement of larger quantum systems." His colleague Witlef Wieczorek remarks: "This resonator can not only be used to generate multi-photon entanglement but also to analyze, for example, molecular formation or carrier dynamics in semiconductors."The results of the Munich team are published in the next issue of Nature Photonics, online on January 31, 2010.
Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1
21.03.2018 | Fraunhofer-Institut für Hochfrequenzphysik und Radartechnik FHR
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21.03.2018 | American Institute of Physics
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
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Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
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For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.
In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
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