Their achievement currently represents the shortest artificial light pulse that has been reported in a refereed journal. Shining this ultrashort light pulse on atoms and molecules can reveal new details of their inner workings—providing benefits to fundamental science as well as potential industrial applications such as better controlling chemical reactions. Working at Italy's National Laboratory for Ultrafast and Ultraintense Optical Science in Milan (as well as laboratories in Padua and Naples), the researchers believe that their current technique will allow them to create even shorter pulses well below 100 attoseconds. Results will be presented in Baltimore at CLEO/QELS, May 6 – May 11.
Whereas humans perceive the world in terms of seconds and minutes, the electrons in atoms and molecules often perform actions on attosecond time scales. How short is this? 130 attoseconds is to one second as a second is to approximately 243 million years—roughly the time that has passed since the first dinosaurs walked the Earth. Aiming a human-made attosecond-scale light pulse on atoms and molecules can trigger new effects in electrons—which are responsible for all chemical reactions—and provide new details on how they work.
In previous experiments, longer pulses, in the higher hundreds of attoseconds, have been created, and the general process is the same. An intense infrared laser strikes a jet of gas, usually argon or neon. The laser’s powerful electric fields rock the electrons back and forth, causing them to release a train of attosecond pulses consisting of high-energy photons in the extreme ultraviolet or soft x-ray part of the spectrum.
Creating a single isolated attosecond pulse, rather than a train of them, is more complex. To do this, the researchers employ their previously developed technique for delivering intense short (5 femtoseconds, or millionths of a billionth of a second) laser pulses to an argon gas target. They use additional optical techniques (including ones borrowed from the research that won the 2005 Nobel Prize in Physics) for creating and shaping a single attosecond pulse. These isolated attosecond pulses promise to probe electron phenomena such as "wavepackets"—specially tailored electron waves inside atoms and molecules that may help scientists use lasers to change the course of chemical reactions for scientific and practical uses, such as controlling the breaking of bonds in complex molecules for medical and pharmaceutical applications.
Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst
Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
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27.03.2017 | Life Sciences