Featured Research

from universities, journals, and other organizations

A stopwatch for electron flashes: duration of energetic electron pulses measured using laser fields

Date:
December 9, 2013
Source:
Ludwig-Maximilians-Universitaet Muenchen (LMU)
Summary:
A stopwatch made of light can determine the duration of extremely brief electron flashes. Scientists have, for the first time, succeeded in measuring the lengths of ultrashort bursts of highly energetic electrons using the electric fields of laser light. Such electron pulses, which behave like ultrashort matter waves, provide time-resolved recordings of processes taking place in molecules and atoms, enabling elementary particles to be "filmed" in four dimensions.

Physicists at LMU Munich and the Max-Planck-Institute of Quantum Optics measure the duration of energetic electron pulses using laser fields.
Credit: Thorsten Naeser

A stopwatch made of light can determine the duration of extremely brief electron flashes. Teams based in the Laboratory for Attosecond Physics (LAP) at LMU and at the Max Planck Institute of Quantum Optics have, for the first time, succeeded in measuring the lengths of ultrashort bursts of highly energetic electrons using the electric fields of laser light. Such electron pulses, which behave like ultrashort matter waves, provide time-resolved recordings of processes taking place in molecules and atoms, enabling elementary particles to be "filmed" in four dimensions. The new stopwatch for electrons now permits even more precise investigations of the motions of electrons and atoms on nature's smallest scales.

A temporal resolution of 24 frames per second is sufficient for a succession of still images to be perceived as smooth motion by the human eye. Recording the motions of atoms and charges within matter, which occur on attosecond scales, requires the acquisition of images at a trillion times that rate. The use of electron pulses offers a way to capture such ultrafast processes. Bunches of electrons can be kicked out of a metal surface using laser light. Each electron pulse lasts for a few femtoseconds (a femtosecond is 1000 attoseconds; an attosecond is a billionth of a billionth of a second) and can deliver an almost instantaneous shot of processes within atoms.

However, exactly how long such pulses last has been difficult to determine. Now the LAP team has developed a system for the precise measurement of the duration of energetic (25 keV) electron pulses. The researchers direct the electron pulses at a thin foil of aluminum. There, they interact with a laser pulse which impinges on the foil perpendicularly to the electrons. Under the influence of the laser's electric field, the electrons either gain or lose some energy before passing straight through the foil to a detector. Whether electrons pick up or lose energy during the encounter depends on the precise timepoint at which they interact with the rapidly oscillating electromagnetic laser field. From the energy spectrum at the electron detector, the scientists can deduce the duration of the original electron pulse prior to its interaction with the laser field.

In contrast to the photons that make up laser light, electrons can penetrate deep into the inner constituents of matter. Hence, they not only measure the chronological sequence of events, but also probe the spatial dispositions of the atoms during a reaction. The investigation of matter with extremely brief electron pulses is called "ultrafast electron diffraction." With this technique, one can determine the positions and movements of atoms and charges in both space and time ‒ i.e. in four dimensions. It is now possible to produce electron pulses that last for several hundreds of femtoseconds but, in principle, even attosecond electron flashes can be generated for electron diffraction. And when they eventually become available, these still shorter electron bunches can also be measured with the new technique. With the new stopwatch made of light, that novel regime no longer seems so far away.


Story Source:

The above story is based on materials provided by Ludwig-Maximilians-Universitaet Muenchen (LMU). Note: Materials may be edited for content and length.


Journal Reference:

  1. F. O. Kirchner, A. Gliserin, F. Krausz, P. Baum. Laser streaking of free electrons at 25keV. Nature Photonics, 2013; DOI: 10.1038/nphoton.2013.315

Cite This Page:

Ludwig-Maximilians-Universitaet Muenchen (LMU). "A stopwatch for electron flashes: duration of energetic electron pulses measured using laser fields." ScienceDaily. ScienceDaily, 9 December 2013. <www.sciencedaily.com/releases/2013/12/131209105024.htm>.
Ludwig-Maximilians-Universitaet Muenchen (LMU). (2013, December 9). A stopwatch for electron flashes: duration of energetic electron pulses measured using laser fields. ScienceDaily. Retrieved September 30, 2014 from www.sciencedaily.com/releases/2013/12/131209105024.htm
Ludwig-Maximilians-Universitaet Muenchen (LMU). "A stopwatch for electron flashes: duration of energetic electron pulses measured using laser fields." ScienceDaily. www.sciencedaily.com/releases/2013/12/131209105024.htm (accessed September 30, 2014).

Share This



More Matter & Energy News

Tuesday, September 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Argentina's Tax Evaders Detected, Hunted Down by Drones

Argentina's Tax Evaders Detected, Hunted Down by Drones

AFP (Sep. 30, 2014) Argentina doesn't only have Lionel Messi the footballer, it has now also acquired "Mesi" the drone system which monitors undeclared mansions, swimming pools and soy fields to curb tax evasion in the country. Duration: 01:18 Video provided by AFP
Powered by NewsLook.com
Do Video Games Trump Brain Training For Cognitive Boosts?

Do Video Games Trump Brain Training For Cognitive Boosts?

Newsy (Sep. 29, 2014) More and more studies are showing positive benefits to playing video games, but the jury is still out on brain training programs. Video provided by Newsy
Powered by NewsLook.com
CERN Celebrates 60 Years of Science

CERN Celebrates 60 Years of Science

Reuters - Business Video Online (Sep. 29, 2014) CERN, the European Organisation for Nuclear Research, celebrates 60 years of bringing nations together through science. As Joanna Partridge reports from inside the famous science centre it's also planning to turn the Large Hadron Collider particle accelerator back on after an upgrade. Video provided by Reuters
Powered by NewsLook.com
This 'Invisibility Cloak' Is Simpler Than Most

This 'Invisibility Cloak' Is Simpler Than Most

Newsy (Sep. 28, 2014) Researchers from the University of Rochester have created a type of invisibility cloak with simple focal lenses. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins