By creating and using the first optical attosecond pulse, scientists from the Laboratory for Attosecond Physics measured the time it takes electrons inside atoms to respond to the electromagnetic forces of light.
In the race to establish ever-faster electronics, light could play an important role. For instance, using light pulses of a precisely controlled waveform, physicists aim to switch electric currents in electronics circuits with light frequencies.
But will electrons in such circuits follow light oscillations instantaneously? How fast will electrons react to the push of a “light-based” button? Or, from a more fundamental perspective: how fast do electrons bound in atoms, molecules or solids respond to light?
Now, an international collaboration of physicists led by Dr. Eleftherios Goulielmakis, head of the research group “Attoelectronics” at the Max Planck Institute of Quantum Optics, researchers from Texas A&M University, USA, and the Lomonosov Moscow State University, have been able to track the effect of this delay for the first time. By creating the first optical attosecond pulse and using it to set electrons in krypton atoms in motion, they discovered that it takes as long as 100 attoseconds for electrons to respond to the electromagnetic forces of light. (Nature, 4 February 2016, DOI: 10.1038/nature16528)
Even for electrons, the lightest particles residing outside the atomic nucleus, quantum mechanics predicts that when exposed to light, a tiny but finite time interval to respond to the forces of light is necessary. But this time interval is predicted to be extremely brief – in the order of tens to hundreds of attoseconds, with one attosecond being one billionth of a billionth of a second. Owing to its brevity, such a phenomenon was considered by scientists immeasurably fast for many decades.
“A prerequisite for capturing such a brief event is a light flash which can pull electrons – or to use the scientific term, polarize them – extremely quickly, and thus probe their response,” said Dr. Mohammed Hassan, a researcher in the group of Dr. Goulielmakis.
With a light-field synthesizer, a device which can manipulate the properties of visible light and nearby infrared and ultraviolet frequencies, the scientists were able to compose visible light pulses as short as 380 attoseconds. These light pulses are so short that they entailed barely more than a half-oscillation of a light field in their time profile. This makes them the fastest pulses of visible light ever created. “We can now not only manipulate visible light with attosecond precision, but also confine its waves into attosecond time intervals,” said Dr. Tran Trung Luu, a researcher in the Attoelectronics group.
With this novel tool at hand, the researchers flashed krypton atoms with optical attosecond pulses. They performed several experiments, each time with a pulse that would apply a slightly different force to the electrons. To check how the electrons responded, they measured the ultraviolet radiation of the wiggling electrons in a vacuum. From the measurements, they were able to deduce that electrons would need some 100 attoseconds to react to the force of light.
“Our study closes a several-decades-long inquiry into the fundamental dynamic response of matter to light fields. From the rotation and the nuclear motion in molecules captured in the last decades with femtosecond technology, we are now able for the first time to track in real time the response of electrons bound in atoms,” Dr. Goulielmakis pointed out. “But at the same time, it opens up a new era of probing and manipulating matter on the electronic level,” he added.
As one of the next steps, Dr. Goulielmakis and his team plan to extend the studies of electron dynamics in solid materials. “Tracing and controlling electrons in solids will enable us to identify the most promising routes for novel ultrafast electronics and photonics operating on sub-fs time scales and at Petahertz clocking rates,” Goulielmakis said.
M. Th. Hassan, T. T. Luu, A. Moulet, O. Raskazovskaya, P. Zhokhov, M. Garg, N. Karpowicz, A. M. Zheltikov, V. Pervak, F. Krausz, and E. Goulielmakis
Optical attosecond pulses and tracking the nonlinear response of bound electrons
Nature, 4 February 2016, DOI: 10.1038/nature16528
Dr. Eleftherios Goulielmakis
ERC Research Group Attoelectronics
Max-Planck-Institute of Quantum Optics
Laboratory for Attosecond Physics
Hans-Kopfermann-Str. 1, 85748 Garching, Germany
Phone: +49(0)89 / 32 905 -632 /Fax: -200
Dr. Olivia Meyer-Streng
Press & Public Relations
Max Planck Institute of Quantum Optics, Garching, Germany
Phone: +49 (0)89 / 32 905 -213
Dr. Olivia Meyer-Streng | Max-Planck-Institut für Quantenoptik
Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt
Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Power and Electrical Engineering
16.01.2017 | Information Technology
16.01.2017 | Power and Electrical Engineering