Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The world's shortest laser pulse

01.11.2017

In order to fully understand the dynamics during a chemical reaction, scientists must be able to study all movements of atoms and molecules on their basic time scale.

Molecules rotate in the range of picoseconds (10-12 s), their atoms vibrate in the range of femtoseconds (10?15 s), and the electrons move in the range of attoseconds (10-18 s). ETH professor Hans Jakob Wörner and his group have now succeeded in generating the world's shortest laser pulse with a duration of only 43 attoseconds.


Thomas Gaumnitz, postdoctoral fellow in the group of ETH professor Hans Jakob Wörner with the setup that generates the shortest laser pulses in the world.

Credit: ETH Zurich

More generally speaking, this laser pulse is the shortest controlled event that has ever been created by humans. The researchers can now observe in high detail how electrons move within a molecule or how chemical bonds are formed.

Breaking down transition states

Starting from an infrared laser, the researchers generate a soft X-ray laser pulse with a very large spectral bandwidth. As a result, various elements including phosphorus and sulphur can be directly observed by exciting their inner-shell electrons. Both elements are present in biomolecules, and it is now possible to observe them with unprecedented time resolution.

But what is the advantage of being able to observe the reaction steps now with even higher resolution? "The faster a charge transfer can take place, the more efficiently a reaction can proceed", says Prof. Wörner. The human eye for example is very efficient when it comes to converting photons into nerve signals.

In rhodopsin, a visual pigment in the retina, the photosensitive molecule retinal is prearranged in such a way that its structure can change extremely fast through the absorption of only a single photon. This enables the visual process even in twilight. A much slower reaction would render vision impossible, because the energy of the photon would be converted to heat in only a few picoseconds.

Attosecond spectroscopy could contribute to the development of more efficient solar cells since it is now for the first time possible to follow the process of excitation through sunlight up to the generation of electricity step by step. A detailed understanding of the charge transfer pathway could help optimizing the efficiency of the next generation of photosensitive elements.

Optical manipulation of the reaction process

Attosecond laser spectroscopy is not only suitable for mere observation, Prof. Wörner explains. Chemical reactions can also be directly manipulated: Using a laser pulse can alter the course of a reaction - even chemical bonds can be broken by stopping the charge shift at a certain location in the molecule. Such targeted interventions in chemical reactions have not been possible until now, since the time scale of electron movement in molecules was previously unreached.

The group of Prof. Wörner is already working on the next generation of even shorter laser pulses. These will make it possible to record even more detailed images, and thanks to a wider X-ray spectrum even more elements can be probed than before. Soon it will be possible to follow the migration of electrons in more complex molecules with an even higher time resolution.

###

Reference

Gaumnitz T, Jain A, Pertot Y, Huppert M, Jordan I, Ardana-Lamas F, Wörner HJ. Streaking of 43-attosecond soft-X-ray pulses generated by a passively CEP-stable mid-infrared driver. Optics Express, Vol. 25, Issue 22 (2017) doi: 10.1364/OE.25.027506

Media Contact

Dr. Hans Jakob Wörner
hansjakob.woerner@phys.chem.ethz.ch
41-446-334-412

 @ETH_en

http://www.ethz.ch/index_EN 

Dr. Hans Jakob Wörner | EurekAlert!

More articles from Physics and Astronomy:

nachricht NASA detects solar flare pulses at Sun and Earth
17.11.2017 | NASA/Goddard Space Flight Center

nachricht Pluto's hydrocarbon haze keeps dwarf planet colder than expected
16.11.2017 | University of California - Santa Cruz

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: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>