Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Attoseconds break into atomic interior

23.02.2018

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very bright, and the photons delivered must have sufficiently high energy. This combination of properties has been sought in laboratories around the world for the past 15 years.


After the interaction of a xenon atom with two photons from an attosecond pulse (purple), the atom is ionized and multiple electrons (green balls) are ejected. This two-photon interaction is made possible by the latest achievements in attosecond technology.

Graphic: Christian Hackenberger

Physicists at the Laboratory for Attosecond Physics (LAP), a joint venture between the Ludwig-Maximilians-Universität Munich (LMU) and the Max Planck Institute of Quantum Optics (MPQ), have now succeeded in meeting the conditions necessary to achieve this goal. In their latest experiments, they have been able to observe the non-linear interaction of an attosecond pulse with electrons in one of the inner orbital shells around the atomic nucleus.

In this context, the term ‘non-linear’ indicates that the interaction involves more than one photon (in this particular case two are involved). This breakthrough was made possible by the development of a novel source of attosecond pulses. One attosecond lasts for exactly one billionth of a billionth of a second.

The door for observing the ultrafast motion of electrons deep inside atoms has been opened. Physicists in the Laboratory for Attosecond Physics (LAP) at the LMU Munich have developed a technology that allows them to generate intense attosecond pulses. These pulses can be used to follow the motion of electrons within the inner shells of atoms in real time by freezing this motion at attosecond shutter speeds.

The experimental procedure used to film electrons in motion makes use of the ‘pump-probe’ approach. Electrons within a target atom are first excited by a photon contained within the pump pulse, which is then followed after a short delay by a second photon in a probe pulse. The latter essentially reveals the effect of the pump photon.

In order to implement this procedure, the photons must be so tightly packed that a single atom within the target can be hit by two photons in succession. Moreover, if these photons are to have a chance of reaching the inner electron shells, they must have energies in the upper end of the extreme ultraviolet (XUV) spectrum. No research group has previously succeeded in generating attosecond pulses with the required photon density in this spectral region.

The technology that has now made this feat possible is based on the upscaling of conventional sources of attosecond pulses. A team led by Prof. Laszlo Veisz has developed a novel high-power laser capable of emitting bursts of infrared light – each consisting of only a few oscillation cycles – which contain 100 times as many photons per pulse as in conventional systems. These pulses, in turn, allow the generation of isolated attosecond pulses of XUV light containing 100 times more photons as in conventional attosecond sources.

In a first series of experiments, the high-energy attosecond pulses were focused on a stream of xenon gas. Photons that happen to interact with an inner shell of a xenon atom eject electrons from that shell and ionize the atom. By using what is known as an ion microscope to detect these ions, the scientists were able, for the first time, to observe the interaction of two photons confined in an attosecond pulse with electrons in the inner orbital shells of an atom. In previous attosecond experiments, it has only been possible to observe the interaction of inner shell electrons with a single XUV photon.

“Experiments in which it is possible to have inner shell electrons interacting with two XUV attosecond pulses are often referred to as the Holy Grail of attosecond physics. With two XUV pulses, we would be able to ‘film’ the electron motion in the inner atomic shells without perturbing their dynamics,” says Dr. Boris Bergues, the leader of the new study. This represents a significant advance on attosecond experiments involving excitation with a single attosecond XUV photon. In those experiments, the resulting state was ‘photographed’ with a longer infrared pulse, which itself had a significant influence on the ensuing electron motion.

“The electron dynamics in the inner shells of atoms are of particular interest, because they result from a complex interplay between many electrons that interact with each other,” as Bergues explains. “The detailed dynamics resulting from these interactions raise many questions, which we can now address experimentally using our new attosecond source.”

In the next step, the physicists plan an experiment in which they will time resolve the interaction by splitting the high-intensity attosecond pulse into separate pump and probe pulses.

The successful application of non-linear optics in the attosecond domain to probe the behaviour of electrons in the inner orbital shells of atoms opens the door to a new understanding of the complex multibody dynamics of subatomic particles. The ability to film the motion of electrons deep in the interior of atoms promises to reveal much about a mysterious realm that has remained hidden from our gaze. Thorsten Naeser

Figure caption:
After the interaction of a xenon atom with two photons from an attosecond pulse (purple), the atom is ionized and multiple electrons (green balls) are ejected. This two-photon interaction is made possible by the latest achievements in attosecond technology.

Original publication:
B. Bergues, D. E. Rivas, M.Weidmann, A. A. Muschet, W. Helml, A. Guggenmoos, V. Pervak, U. Kleineberg, G. Marcus, R. Kienberger, D. Charalambidis, P. Tzallas, H. Schröder, F. Krausz, and L. Veisz
Table-Top Nonlinear Optics in the 100-eV Spectral Region
Optica, Vol. 5, Issue 3, pp. 237-242 (2018); doi.org/10.1364/OPTICA.5.000237

Contact:

Dr. Boris Bergues
Laboratory for Attosecond Physics
Department of Physics, LMU Munich and
Max Planck Institute of Quantum Optics
Hans-Kopfermann-Str. 1
85748 Garching, Germany
Phone: +49 (0)89 32 905 -330
E-mail: boris.bergues@mpq.mpg.de

Prof. Dr. Laszlo Veisz
Relativistic Attosecond Physics Laboratory
Department of Physics
Umea University
Linnaeus vag 24
SE-90187 Umea, Sweden
Phone: +46 (0)90 786 66 62
E-mail: laszlo.veisz@umu.se

Dr. Olivia Meyer-Streng
Press & Public Relations
Max Planck Institute of Quantum Optics
85748 Garching, Germany
Phone: +49 (0)89 / 32 905 - 213
E-mail: olivia.meyer-streng@mpq.mpg.de

Dr. Olivia Meyer-Streng | Max-Planck-Institut für Quantenoptik
Further information:
http://www.mpq.mpg.de/

More articles from Physics and Astronomy:

nachricht Extremely close look at electron advances frontiers in particle physics
18.10.2018 | National Science Foundation

nachricht Blue phosphorus -- mapped and measured for the first time
16.10.2018 | Helmholtz-Zentrum Berlin für Materialien und Energie

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: Goodbye, silicon? On the way to new electronic materials with metal-organic networks

Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.

Silicon, a so called semiconductor, is currently widely employed for the development of components such as solar cells, LEDs or computer chips. High purity...

Im Focus: Storage & Transport of highly volatile Gases made safer & cheaper by the use of “Kinetic Trapping"

Augsburg chemists present a new technology for compressing, storing and transporting highly volatile gases in porous frameworks/New prospects for gas-powered vehicles

Storage of highly volatile gases has always been a major technological challenge, not least for use in the automotive sector, for, for example, methane or...

Im Focus: Disrupting crystalline order to restore superfluidity

When we put water in a freezer, water molecules crystallize and form ice. This change from one phase of matter to another is called a phase transition. While this transition, and countless others that occur in nature, typically takes place at the same fixed conditions, such as the freezing point, one can ask how it can be influenced in a controlled way.

We are all familiar with such control of the freezing transition, as it is an essential ingredient in the art of making a sorbet or a slushy. To make a cold...

Im Focus: Micro energy harvesters for the Internet of Things

Fraunhofer IWS Dresden scientists print electronic layers with polymer ink

Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed...

Im Focus: Dynamik einzelner Proteine

Neue Messmethode erlaubt es Forschenden, die Bewegung von Molekülen lange und genau zu verfolgen

Das Zusammenspiel aus Struktur und Dynamik bestimmt die Funktion von Proteinen, den molekularen Werkzeugen der Zelle. Durch Fortschritte in der...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Conference to pave the way for new therapies

17.10.2018 | Event News

Berlin5GWeek: Private industrial networks and temporary 5G connectivity islands

16.10.2018 | Event News

5th International Conference on Cellular Materials (CellMAT), Scientific Programme online

02.10.2018 | Event News

 
Latest News

RUDN chemist tested a new nanocatalyst for obtaining hydrogen

18.10.2018 | Life Sciences

Massive organism is crashing on our watch

18.10.2018 | Earth Sciences

Electrical enhancement: Engineers speed up electrons in semiconductors

18.10.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>