Nav: Home

Processes in the atomic microcosmos are revealed

May 16, 2018

Physicists at Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have successfully generated controlled electron pulses in the attosecond range. They used optical travelling waves that are formed by laser pulses of varying wavelengths. The movements of electrons in atoms were revealed using attosecond free-electron pulses. The findings of the researchers from Erlangen have been published in the acclaimed journal Physical Review Letters (DOI: 10.1103/PhysRevLett.120.103203).

Scientists have been researching ways of generating packets of electrons in extremely short timescales for several years. Such pulses enable ultrafast movements to be tracked, for example vibrations in atomic lattices, phase transitions in materials or molecular bonds in chemical reactions. 'The shorter the pulse, the faster the movements that can be mapped,' explains Prof. Dr. Peter Hommelhoff, Chair of Laser Physics at FAU. 'However, this also involves the special challenge of how to control the packets of electrons.' Last year, Hommelhoff and his team successfully generated periodic electron pulses with a duration of 1.3 femtoseconds - a femtosecond is one quadrillionth of a second. To do so, they directed a continuous beam of electrons over a silicon lattice and superimposed it with the optical field of laser pulses.

From femtosecond to attosecond pulses

The researchers at FAU have now gone one better and have generated electron pulses of 0.3 femtoseconds or 300 attoseconds. Lasers were also used for this method. Firstly, packets of electrons are emitted from an electron source using ultraviolet laser pulses. These packets then interact with optical travelling waves that are formed in a vacuum by two infrared laser pulses of varying wavelengths. 'The ponderomotive interaction causes a shift in the electron density,' explains Norbert Schönenberger, a researcher at Prof. Hommelhoff's Chair and co-author of the study. 'We break down the electron packet to a certain extent into even smaller packets to generate electron pulses in the attosecond range. The time delay in the arrival of the laser beams enables us to generate specific travelling waves and thus precisely control the trains of pulses.'

This method developed by the physicists at FAU could revolutionise experiments in electron diffraction and microscopy. In future, attosecond pulses will not only be able to be used to trace the movements of atoms , but also even to show the dynamics of electrons within atoms, molecules and solid bodies. The results have been published under the title 'Ponderomotive Generation and Detection of Attosecond Free-Electron Pulse Trains' in the renowned journal Physical Review Letters.
-end-


University of Erlangen-Nuremberg

Related Electrons Articles:

Deceleration of runaway electrons paves the way for fusion power
Fusion power has the potential to provide clean and safe energy that is free from carbon dioxide emissions.
Shining light on low-energy electrons
The classic method for studying how electrons interact with matter is by analyzing their scattering through thin layers of a known substance.
Ultrafast nanophotonics: Turmoil in sluggish electrons' existence
An international team of physicists has monitored the scattering behavior of electrons in a non-conducting material in real-time.
NASA mission uncovers a dance of electrons in space
NASA's MMS mission studies how electrons spiral and dive around the planet in a complex dance dictated by the magnetic and electric fields, and a new study revealed a bizarre new type of motion exhibited by these electrons.
'Hot' electrons don't mind the gap
Rice University scientists discover that 'hot' electrons can create a photovoltage about a thousand times larger than ordinary temperature differences in nanoscale gaps in gold wires.
Electrons used to control ultrashort laser pulses
We may soon get better insight into the microcosm and the world of electrons.
Supercool electrons
Study of electron movement on helium may impact the future of quantum computing.
Two electrons go on a quantum walk and end up in a qudit
There is a variety of physical systems that can be used to implement a separate quantum bit, but significantly less research has been done into systems of several qubits or qudits.
Radiation that knocks electrons out and down, one after another
Researchers at Japan's Tohoku University are investigating novel ways by which electrons are knocked out of matter.
Controlling electrons in time and space
A new method has been developed to control electrons being emitted from metal tips.

Related Electrons Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Setbacks
Failure can feel lonely and final. But can we learn from failure, even reframe it, to feel more like a temporary setback? This hour, TED speakers on changing a crushing defeat into a stepping stone. Guests include entrepreneur Leticia Gasca, psychology professor Alison Ledgerwood, astronomer Phil Plait, former professional athlete Charly Haversat, and UPS training manager Jon Bowers.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".