A perfect interface between free-space and integrated optical systems. New class of integrated nanophotonic devices–a world record in simultaneous control of all four optical degrees of freedom–can convert light initially confined in an optical waveguide to an arbitrary optical pattern in free space. Researchers at Columbia Engineering have developed a new class of integrated photonic devices–“leaky-wave metasurfaces”–that can convert light initially confined in an optical waveguide to an arbitrary optical pattern in free space. These devices are the first to…
The motion of an electron in a strong infrared laser field is tracked in real time by means of a novel method developed by MPIK physicists and applied to confirm quantum-dynamics theory by cooperating researchers at MPI-PKS. The experimental approach links the absorption spectrum of the ionizing extreme ultraviolet pulse to the free-electron motion driven by the subsequent near-infrared pulse. For this experimental scheme, the classical description of the electron motion is justified even though it is a quantum object….
”When pentacene is excited by light, the electrons in the material rapidly react,” explains Prof. Ralph Ernstorfer, a senior author of the study. “It was an open and very disputed question whether a photon excites two electrons directly or initially one electron, which subsequently shares its energy with another electron.” To unravel this mystery the researchers used time- and angle-resolved photoemission spectroscopy, a cutting-edge technique to observe the dynamics of electrons on the femtosecond time scale, which is a billionth…
Alexandrite laser crystals are well suited for use in earth observation satellites. They are robust and enable laser systems with a tunable output wavelength. In the European Horizon 2020 project GALACTIC, the partners Laser Zentrum Hannover e.V. (LZH), Optomaterials S.r.l. (Italy) and Altechna (Lithuania) have now succeeded in establishing a solely European supply chain for alexandrite laser crystals, which can be used for space applications. The Italian partner Optomaterials produces competitive crystals, which the Lithuanian company Altechna provides with a…
Manual can help debug and design nanomagnet devices. An international team of researchers at the University of California, Riverside, and the Institute of Magnetism in Kyiv, Ukraine, has developed a comprehensive manual for engineering spin dynamics in nanomagnets – an important step toward advancing spintronic and quantum-information technologies. Despite their small size, nanomagnets — found in most spintronic applications — reveal rich dynamics of spin excitations, or “magnons,” the quantum-mechanical units of spin fluctuations. Due to its nanoscale confinement, a…
Researchers in Germany and the U.S.A. have shown for the first time that terahertz (THz) light pulses can stabilize ferromagnetism in a crystal at temperatures more than three times its usual transition temperature. As the team reports in Nature, using pulses just hundreds of femtoseconds long (a millionth of a billionth of a second), a ferromagnetic state was induced at high temperature in the rare-earth titanate YTiO₃ which persisted for many nanoseconds after the light exposure. Below the equilibrium transition…
They are called UFOs, but aliens have nothing to do with them. They are the ultra-fast outflows: space winds that emerge from the surroundings of supermassive black holes and blow at speeds close to that of light. An international research team has explored this still little-understood phenomenon, hunting for these gas emissions, which are crucial to understanding the mechanisms regulating the behaviour of supermassive black holes in their active phase. The research project is called SUBWAYS (SUper massive Black hole Winds in the x-rAYS) and the first…
GOES-U, the fourth and final satellite in NOAA’s GOES-R Series, recently completed a successful test deployment of its solar array to ensure it will function properly in space. This critical test verified that the satellite’s large, five-panel solar array — which is folded up when the satellite is launched — will properly deploy when GOES-U reaches geostationary orbit. During this test, engineers unfurled the five panels on rails that simulated the zero-gravity environment of space. Each solar panel is approximately 13…
Extreme pressures rearrange atoms to reveal interesting new properties. For decades, scientists sought a way to apply the outstanding analytical capabilities of neutrons to materials under pressures approaching those surrounding the Earth’s core. These extreme pressures can rearrange a material’s atoms, potentially resulting in interesting new properties. A breakthrough resulted in 2022 when researchers at Oak Ridge National Laboratory’s Spallation Neutron Source squeezed a tiny sample of material – sandwiched between two diamonds – to a record 1.2 million times the average…
The algorithm pairs machine-learning techniques with classical beam physics equations to avoid massive data crunching. Whenever SLAC National Accelerator Laboratory’s linear accelerator is on, packs of around a billion electrons each travel together at nearly the speed of light through metal piping. These electron bunches form the accelerator’s particle beam, which is used to study the atomic behavior of molecules, novel materials and many other subjects. But trying to estimate what a particle beam actually looks like as it travels…
Most massive touching stars ever found will eventually collide as black holes. Two massive touching stars in a neighbouring galaxy are on course to become black holes that will eventually crash together, generating waves in the fabric of space-time, according to a new study by researchers at University College London and the University of Potsdam. The study, accepted for publication in the journal “Astronomy & Astrophysics”, looked at a known binary star (two stars orbiting around a mutual centre of…
The most common stars in the universe are red dwarf stars, which means that rocky exoplanets are most likely to be found orbiting such a star. Red dwarf stars are cool, so a planet has to hug it in a tight orbit to stay warm enough to potentially host liquid water (meaning it lies in the habitable zone). Such stars are also active, particularly when they are young, releasing ultraviolet and X-ray radiation that could destroy planetary atmospheres. As a…
A team of Japanese astronomers used simultaneous ground-based and space-based observations to capture a more complete picture of a superflare on a star. The observed flare started with a very massive, high-velocity prominence eruption. These results give us a better idea of how superflares and stellar prominence eruptions occur. Some stars have been seen releasing superflares over 10 times larger than the largest solar flare ever seen on the Sun. The hot ionized gas released by solar flares can influence…
An international team of scientists with participation of the MPIfR in Bonn has used new millimetre-wavelength observations to image for the first time the link between the ring-like structure that reveals the matter falling into the central black hole and the powerful relativistic jet in the prominent radio galaxy M87. These images show the origin of the jet and the accretion flow near the central supermassive black hole. The new observations at 3.5 mm wavelength were obtained with the Global…
FAU physicists measure and control electron release from metals in the attosecond range. By superimposing two laser fields of different strengths and frequency, the electron emission of metals can be measured and controlled precisely to a few attoseconds. Physicists from FAU, the University of Rostock and the University of Konstanz have shown that this is the case. The findings could lead to new quantum-mechanical insights and enable electronic circuits that are a million times faster than today. The researchers have…
… with high phase purity. Researchers provide direct evidence that the magnetic properties of the novel icosahedral quasicrystals depend on the electrons-per-atom ratio. Quasicrystals (QCs) have peculiar structures with interesting atomic arrangements. Although they are similar to crystals from the exterior, at the atomic scale, they lack periodicity despite being ordered. Such structural arrangements confer quasicrystals with symmetries and other special properties that are missing in crystals. In particular, icosahedral QCs (i QCs), which have a special geometric structure, show…
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