Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Billard game in an atom

08.05.2012
Physicists from the Max Planck Institute of Quantum Optics trace the double ionization of argon atoms on attosecond time scales.

When an intense laser pulse interacts with an atom it generates agitation on the micro scale. A rather likely outcome of this interaction is single ionization, where one electron is ejected from the atom. From time to time, however, two electrons can be removed from the atom, resulting in the more complex process of double ionization.


Picture 1: Artist's view of non-sequential double ionization. The 3D plots on the circle were obtained from experimental data and show how the velocities of the two electrons change with the electric-field evolution of the ionizing pulse. The plot in the center is the sum of all these single measurements. From these data, the scientists can reconstruct the detailed process of the double ionization. Courtesey of Christian Hackenberger/ LMU


Picture 2: A scientist of the laboratory for attosecond physics working with the COLTRIMS (Cold Target Recoil Ion Momentum Spectroscopy) apparatus, which is used to perform the experiments on double ionization. Courtesey of Thorsten Naeser/LMU

The detailed course of this process on attosecond time scales (an attosecond is a billionth of a billionth of a second) has been observed by an international team lead by researchers from the Laboratory for Attosecond Physics at the Max Planck Institute of Quantum Optics in close collaboration with colleagues from the Max Planck Institute for Nuclear Physics. The researchers report on their results in Nature Communications (8th May 2012).

The process is reminiscent of a billiard game, where, after a collision, a ball brings another one in motion. The so called non-sequential double ionization investigated by the researchers bears many similarities with such a billiard ball collision. The strong laser light first ejects an electron from the atom, accelerates it away from and then back towards the atomic core. During the collision the electron transfers part of its energy onto a second electron, which is promoted into an excited state of the core. A little later, the electric field of the laser pulse also liberates the second electron from the atomic core. The non-sequential double ionization usually consists of many such recollision and excitation events, which hampers the interpretation of experimental results.
In close collaboration with colleagues from the Max Planck Institute for Nuclear Physics scientists from the Laboratory for Attosecond Physics at the Max Planck Institute of Quantum Optics and international collaborators have now succeeded in confining such a non-sequential double ionization to a single recollision and excitation event allowing for tracing this process on attosecond time scales.

To achieve this, the scientists sent a four femtosecond long laser pulse onto argon atoms (a femtosecond is a millionth of a billionth of a second). The light wave of this pulse essentially consisted of two wave maxima and two wave minima, i.e two cycles. Due to the action of the laser field, most atoms were singly ionized. Every thousandth atom, however, underwent non-sequential double ionization: After the ionization of the first electron just after the first wave maximum, it took approximately 1.8 femtoseconds for it to revisit the atomic core and excite a second electron. The electron stayed in the excited state for about 400 attoseconds before the laser field released it from the core just before the second wave maximum. „We were surprised to see that the second electron leaves the atomic core 200 attoseconds before the maximum of the second cycle“, said Boris Bergues, a scientist in the LAP-Team. It was assumed so far that the second electron escapes the atomic core at the maximum of a cycle.

Through their observations, the scientists gave a deep insight into the quantum dynamics of a laser-driven multi-electron system. Following such dynamics on attosecond time scales is essential for refining our fundamental understanding of matter-light interactions. Application of the experimental technique to the study of molecules might shed light, one day, on more complex 'billiard games' played by multiple electrons in the course of chemical reaction. [Thorsten Naeser]

Original Publication:
Boris Bergues, Matthias Kübel, Nora G. Johnson, Bettina Fischer, Nicolas Camus, Kelsie J. Betsch, Oliver Herrwerth, Arne Senftleben, A. Max Sayler, Tim Rathje, Thomas Pfeifer, Itzik Ben-Itzhak, Robert R. Jones, Gerhard G. Paulus, Ferenc Krausz, Robert Moshammer, Joachim Ullrich,
Matthias F. Kling

Attosecond Tracing of Correlated Electron-Emission in Non-Sequential Double Ionization, Nature Communications, 8th May 2012

For further information, please contact:

Dr. Boris Bergues
Laboratory for Attosecond Physics
Max Planck Institute of Quantum Optics
Hans-Kopfermann-Str. 1
D-85748 Garching
Phone: +49 (0) 89 / 32905 -323
E-mail: boris.bergues@mpq.mpg.de

Dr. Matthias Kling
Max Planck Institute of Quantum Optics
Hans-Kopfermann-Str. 1
D-85748 Garching
Phone: +49 (0) 89 / 32905 -234
E-mail: matthias.kling@mpq.mpg.de
http://www.attoworld.de/kling-group/

Priv.-Doz. Dr. Robert Moshammer
Max Planck Institute for Nuclear Physics, Heidelberg
Phone: +49 (0) 6221 / 516 -461
E-mail: robert.moshammer@mpi-hd.mpg.de

Dr. Olivia Meyer-Streng
Max Planck Institute of Quantum Optics
Press and Public Relations
Phone: +49 (0) 89 / 32905 -213
E-mail: olivia.meyer-streng@mpq.mpg.de

Dr. Olivia Meyer-Streng | Max-Planck-Institut
Further information:
http://www.mpq.mpg.de
http://www.attoworld.de/kling-group/

More articles from Physics and Astronomy:

nachricht Tiny lasers from a gallery of whispers
20.09.2017 | American Institute of Physics

nachricht New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>