Amid a fast game in a vast venue, sports photography seeks to freeze motion and isolate small portions of space for special consideration. In the scientific world of the ultrafast and ultrasmall, stroboscopic effects are achieved with greatly attenuated laser pulses. The advent of laser light served up in femtosecond (or 10^-15 second) bursts has helped to elucidate the molecular world by freezing their vibrational and rotational motions. Scientists would of course like to instigate and monitor even shorter times and distances.
A collaboration between scientists at the Technical University of Vienna and the Max Planck Institute for Quantum Optics (MPQ) has now done precisely this. They have produced a series of 2.5-fsec pulses, each consisting of only a few cycles of a carrier light signal modulated within an amplitude envelope. In the case of the Vienna-MPQ experiment, however, all the pulses are identical (a feat not achieved previously) and the phase of the carrier wave within the envelope is controlled with a time resolution of about 100 attoseconds.
When the intense (100 GW) few-cycle pulse strikes an atom, an electron can be stripped away quickly, and reabsorbed just as quickly. This violent excursion results in the emission of a sharp x-ray spike with a duration even shorter than the pulse that excited the reaction. In fact the x-ray pulses are about 500 attoseconds long. Moreover, because all the waveforms of the optical pulse are identical, and controlled, the subsequent electron motions and x-ray emissions are also highly controlled and reproducible. At a talk at this weeks meeting of the American Association for the Advancement of Science (AAAS) in Denver, Vienna physicist Ferenc Krausz said that this sub-femtosecond control of electron currents represented true attophysics, a new technique for directing and watching atomic processes at unprecedentedly short time intervals. (See Baltuska et al., Nature, 6 February 2003.)
Phillip F. Schewe | PHYSICS NEWS UPDATE
Only an atom thick: Physicists succeed in measuring mechanical properties of 2D monolayer materials
17.01.2018 | Universität des Saarlandes
Black hole spin cranks-up radio volume
15.01.2018 | National Institutes of Natural Sciences
What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...
For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.
Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...
At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.
No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...
Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.
Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...
The oceans are the largest global heat reservoir. As a result of man-made global warming, the temperature in the global climate system increases; around 90% of...
08.01.2018 | Event News
11.12.2017 | Event News
08.12.2017 | Event News
17.01.2018 | Ecology, The Environment and Conservation
17.01.2018 | Physics and Astronomy
17.01.2018 | Awards Funding