Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

A zeptosecond stopwatch for the microcosm

08.11.2016

For the first time ever, physicists from Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics have recorded an internal atomic event with an accuracy of a trillionth of a billionth of a second.

When light strikes electrons in atoms, their state can change unimaginably quickly. The laser physicists at Ludwig-Maximilians-Universität (LMU) and the Max Planck Institute of Quantum Optics (MPQ) have measured such a phenomenon – namely that of photoionization, in which an electron exits a helium atom after excitation by light – for the first time with zeptosecond precision.


Once a photon has removed an electron from a helium atom, it is possible to calculate the probable position of the remaining electron. The likeliest position of the electron is shown in the image as the brightest area around the atomic nucleus (which itself is not visible in the image). Image: Schultze/Ossiander

A zeptosecond is a trillionth of a billionth of a of a second (10-21 seconds). This is the greatest accuracy of time determination of an event in the microcosm ever achieved, as well as the first absolute determination of the timescale of photoionization.

If light hits the two electrons of a helium atom, you must be incredibly fast to observe what occurs. Besides the ultra-short periods in which changes take place, quantum mechanics also comes into play. If a light particle (photon) hits the two electrons, either the entire energy of the photon can be absorbed by one of the electrons, or a division can take place.

Regardless of the energy transfer, one electron leaves the helium atom. This process is called photoemission, or the photoelectric effect, and was discovered by Albert Einstein at the beginning of last century.

It takes between five and fifteen attoseconds (1 as is 10-18 second) from the time a photon interacts with the electrons to the time one of the electrons leaves the atom, as physicists already discovered in recent years (Science, 25 June 2010).

With their improved measurement method, laser physicists can accurately measure events at a rate of up to 850 zeptoseconds. The researchers shone an attosecond-long, extremely ultraviolet (XUV) light pulse onto a helium atom to excite the electrons. At the same time, they fired a second infrared laser pulse, lasting about four femtoseconds (1 fs is 10-15 seconds).

The electron was detected by the infrared laser pulse as soon as it left the atom following excitation by XUV light. Depending on the exact electromagnetic field of this pulse at the time of detection, the electron was accelerated or decelerated. Through this change in speed, the physicists were able to measure photoemission with zeptosecond precision. Additionally, the researchers were also able to determine for the first time how the energy of the incident photon quantum-mechanically divided between the two electrons of the helium atom in a few attoseconds before the emission of one of the particles.

“The understanding of these processes within the helium atom provides us with a tremendously reliable basis for future experiments,” explains Martin Schultze, leader of the experiments at the MPQ. The physicists were able to correlate the zeptosecond precision of their experiments with the theoretical predictions of their peers from the Institute of Theoretical Physics at the Technical University of Vienna.

With its two electrons, helium is the only system that can be calculated completely quantum mechanically. This makes it possible to reconcile theory and experiment. “We can now derive the complete wave mechanic description of the interconnected systems of electron and ionized helium mother atoms from our measurements,” says Schultze.

With their metrology experiments in zeptosecond time dimensions, the laser physicists have maneuvered another important puzzle piece in the quantum mechanics of the helium atom into position, and thus advanced measuring accuracy in the microcosm to a whole new dimension.
Thorsten Naeser

Original publication:
M. Ossiander, F. Siegrist, V. Shirvanyan, R. Pazourek, A. Sommer, T. Latka, A. Guggenmos, S. Nagele, J. Feist, J. Burgdörfer, R. Kienberger and M. Schultze
Attosecond correlation dynamics
Nature physics, 7. November 2016, doi: 10.1038/nphys3941

For further information, contact:
Dr. Martin Schultze
Max Planck Institute of Quantum Optics, Garching
Tel: +49 89 32905- 236
Fax: +49 89 32905-649
E-Mail: Martin.Schultze@mpq.mpg.de

Prof. Ferenc Krausz
Ludwig-Maximilians-Univ. München, Faculty of Physics
Max Planck Institute of Quantum Optics, Garching
Tel: +49 89 32905-612
E-Mail: krausz@lmu.de
http://www.attoworld.de

Dr. Olivia Meyer-Streng | Max-Planck-Institut für Quantenoptik

More articles from Physics and Astronomy:

nachricht Supporting structures of wind turbines contribute to wind farm blockage effect
13.12.2019 | American Institute of Physics

nachricht Chinese team makes nanoscopy breakthrough
13.12.2019 | Chinese Academy of Sciences Headquarters

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: Virus multiplication in 3D

Vaccinia viruses serve as a vaccine against human smallpox and as the basis of new cancer therapies. Two studies now provide fascinating insights into their unusual propagation strategy at the atomic level.

For viruses to multiply, they usually need the support of the cells they infect. In many cases, only in their host’s nucleus can they find the machines,...

Im Focus: Cheers! Maxwell's electromagnetism extended to smaller scales

More than one hundred and fifty years have passed since the publication of James Clerk Maxwell's "A Dynamical Theory of the Electromagnetic Field" (1865). What would our lives be without this publication?

It is difficult to imagine, as this treatise revolutionized our fundamental understanding of electric fields, magnetic fields, and light. The twenty original...

Im Focus: Highly charged ion paves the way towards new physics

In a joint experimental and theoretical work performed at the Heidelberg Max Planck Institute for Nuclear Physics, an international team of physicists detected for the first time an orbital crossing in the highly charged ion Pr⁹⁺. Optical spectra were recorded employing an electron beam ion trap and analysed with the aid of atomic structure calculations. A proposed nHz-wide transition has been identified and its energy was determined with high precision. Theory predicts a very high sensitivity to new physics and extremely low susceptibility to external perturbations for this “clock line” making it a unique candidate for proposed precision studies.

Laser spectroscopy of neutral atoms and singly charged ions has reached astonishing precision by merit of a chain of technological advances during the past...

Im Focus: Ultrafast stimulated emission microscopy of single nanocrystals in Science

The ability to investigate the dynamics of single particle at the nano-scale and femtosecond level remained an unfathomed dream for years. It was not until the dawn of the 21st century that nanotechnology and femtoscience gradually merged together and the first ultrafast microscopy of individual quantum dots (QDs) and molecules was accomplished.

Ultrafast microscopy studies entirely rely on detecting nanoparticles or single molecules with luminescence techniques, which require efficient emitters to...

Im Focus: How to induce magnetism in graphene

Graphene, a two-dimensional structure made of carbon, is a material with excellent mechanical, electronic and optical properties. However, it did not seem suitable for magnetic applications. Together with international partners, Empa researchers have now succeeded in synthesizing a unique nanographene predicted in the 1970s, which conclusively demonstrates that carbon in very specific forms has magnetic properties that could permit future spintronic applications. The results have just been published in the renowned journal Nature Nanotechnology.

Depending on the shape and orientation of their edges, graphene nanostructures (also known as nanographenes) can have very different properties – for example,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

The Future of Work

03.12.2019 | Event News

First International Conference on Agrophotovoltaics in August 2020

15.11.2019 | Event News

Laser Symposium on Electromobility in Aachen: trends for the mobility revolution

15.11.2019 | Event News

 
Latest News

Supporting structures of wind turbines contribute to wind farm blockage effect

13.12.2019 | Physics and Astronomy

Chinese team makes nanoscopy breakthrough

13.12.2019 | Physics and Astronomy

Tiny quantum sensors watch materials transform under pressure

13.12.2019 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>