Scientists observe escaping electrons for first time
[Date: 2007-04-06]
For
the first time, researchers have observed electrons using the energy of
a laser to escape the forces binding them to an atom.
The work was partly funded by the EU under the Marie Curie section
of the Sixth Framework Programme (FP6), and is published in the journal
Nature.
Normally, strong forces keep electrons in their orbits around the
nucleus of atoms. Trying to overcome this force is like climbing a
steep mountain. However, in the world of quantum physics, there is an
escape route: with a bit of help from the energy of a laser field, the
electrons can tunnel through the 'mountain' to freedom.
This tunnelling process is so fast (it lasts just a few hundred
attoseconds, an attosecond being a billionth of a billionth of a
second) that until now scientists have lacked the means to observe it
in real time.
Together with colleagues from Germany, Austria, the Netherlands and
Russia, Ferenc Krausz of the Max Planck Institute for Quantum Optics
fired a pulse of ultraviolet light just 250 attoseconds long at neon
atoms, timed to match the oscillations of a red laser pulse. The
researchers were able to measure the levels of neon ions which had lost
an electron during these brief moments, and so observe the tunnelling
process indirectly.
'These experiments don't just provide us with the first ever
insight into the dynamics of electron tunnelling,' commented Professor
Krausz, 'We have also shown that the movement of electrons in atoms or
molecules can be observed in real time with the help of laser
field-induced tunnelling.'
The researchers hope that understanding how electrons behave at
this scale will lead to new developments in microelectronics, the
development of compact x-ray light sources, biological imaging and
radiotherapy.
Max Planck Society:
http://www.mpg.de/
Nature:
http://www.nature.com/nature
Category: Projects
Data Source Provider: Max Planck Society/Nature
Document Reference: Uiberacker, M. et al. (2007) Attosecond real-time observation of electron tunnelling in atoms. Nature 446: 627-632.
Programme or Service Acronym: MS-A C, MS-D C, MS-NL C, FP6-MOBILITY, FP6-STRUCTURING, FRAMEWORK 6C
Subject Index: Coordination, Cooperation; Electronics, Microelectronics; Measurement Methods; Scientific Research; Other Technology
RCN: 27464