Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Incredibly short light pulses capture our microscopic world

03.05.2006


An international collaboration including researchers from Amsterdam, Paris, Baton Rouge (USA) and Lund University, (Sweden), has made a breakthrough which moves some of the mathematics of quantum mechanics off of the blackboard and into the laboratory - from theory to reality. Using extremely short pulses of light, new knowledge about the wave-like nature of matter can be obtained.



The Lund group presently holds the world record for producing short laser pulses. In the High-power laser facility at the Lund University, trains of pulses where each pulse is 200 attoseconds long and separated from the next pulse by 1.3 femtoseconds, are routinely produced. A femtosecond is 10-15 seconds, i.e. one-millionth-of-a-billionth of a second, while an attosecond is still one thousand times shorter. These incredibly short light pulses allow scientists to make snapshots of the most rapidly moving constituents of atoms and molecules, the electrons. In a paper published in this month’s issue of Nature Physics, the scientists demonstrate that attosecond pulses are an extremely powerful tool for studying the wave-like nature of electrons.

Quantum mechanics describes all the properties of matter in a probabilistic manner with so-called wave functions. Wave functions describe, for example, the probability that an electron is found at a particular position or that an electron moves with a particular velocity. They also describe how – similar to light - matter sometimes behaves more like a particle, and sometimes more like a wave. Importantly, the wave function is – in mathematical terms - a complex quantity, that it is characterized by both an amplitude and a phase. Though theorists can calculate complex valued wave functions and use them to make precise predictions about the behaviour of matter, the complete measurement of a wave function, both its amplitude and phase, is notoriously difficult. This is why most experiments only give information about the amplitudes of wave functions and not their phase.


In their paper, the scientists now report that they have developed a technique for measuring the phase of an electronic wave function, making use of attosecond pulses. The technique is based on interferences between electrons that are created by two attosecond pulses that quickly follow each other. The technique combines the ultrashort light pulses generated in Lund with an electron imaging detector that was built in Amsterdam and moved to Lund for the experiment. In the experiments, argon atoms were ionized by a series of attosecond pulses in the extreme ultraviolet wavelength range in the presence of longer pulses of intense infrared laser light. When the argon atoms absorb the extreme ultraviolet light of the attosecond pulses, electrons escape in bunches (called wave packets). The intense infrared light changes the velocity of the electron wave packets, and they start to interfere with each other and form complicated interference patterns. The analysis of the interference patterns allowed the scientists to get unprecedented insight into the wave-nature of the electron and to extract information on the phase of the electronic wave function.

The experiment is presented in an article titled "Attosecond electron wave packet interferometry".

Göran Frankel | alfa
Further information:
http://www.nature.com/naturephysics

More articles from Physics and Astronomy:

nachricht First chip-scale broadband optical system that can sense molecules in the mid-IR
24.05.2018 | Columbia University School of Engineering and Applied Science

nachricht Nuclear physicists leap into quantum computing with first simulations of atomic nucleus
24.05.2018 | DOE/Oak Ridge National Laboratory

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: Molecular switch will facilitate the development of pioneering electro-optical devices

A research team led by physicists at the Technical University of Munich (TUM) has developed molecular nanoswitches that can be toggled between two structurally different states using an applied voltage. They can serve as the basis for a pioneering class of devices that could replace silicon-based components with organic molecules.

The development of new electronic technologies drives the incessant reduction of functional component sizes. In the context of an international collaborative...

Im Focus: LZH showcases laser material processing of tomorrow at the LASYS 2018

At the LASYS 2018, from June 5th to 7th, the Laser Zentrum Hannover e.V. (LZH) will be showcasing processes for the laser material processing of tomorrow in hall 4 at stand 4E75. With blown bomb shells the LZH will present first results of a research project on civil security.

At this year's LASYS, the LZH will exhibit light-based processes such as cutting, welding, ablation and structuring as well as additive manufacturing for...

Im Focus: Self-illuminating pixels for a new display generation

There are videos on the internet that can make one marvel at technology. For example, a smartphone is casually bent around the arm or a thin-film display is rolled in all directions and with almost every diameter. From the user's point of view, this looks fantastic. From a professional point of view, however, the question arises: Is that already possible?

At Display Week 2018, scientists from the Fraunhofer Institute for Applied Polymer Research IAP will be demonstrating today’s technological possibilities and...

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

When corals eat plastics

24.05.2018 | Ecology, The Environment and Conservation

Surgery involving ultrasound energy found to treat high blood pressure

24.05.2018 | Medical Engineering

First chip-scale broadband optical system that can sense molecules in the mid-IR

24.05.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>