Infrared light boosts electrons during their ejection from a surface
http://focus.aps.org/story/v18/st10
Phys. Rev. Lett. 97, 113604
(issue of 15 September 2006)
26 September 2006
Ultraviolet light can eject electrons from a solid surface, a
phenomenon known as the photoelectric effect. Albert Einstein got his
only Nobel Prize for explaining it a century ago. Now, in the 15
September PRL, researchers report that intense infrared light can
work with the ultraviolet to boost or retard the emitted electrons.
This "laser-assisted photoelectric effect," previously seen only in
clouds of atoms, could allow them to track the intricate dance of
electrons in solids over times much shorter than a femtosecond,
10^-15 seconds.
Researchers first saw the laser-assisted photoelectric effect (LAPE)
a decade ago by simultaneously hitting a cloud of atoms with both
ultraviolet (UV) and infrared pulses [1]. With just a UV pulse, the
ejected electrons formed narrow peaks in the energy spectrum, with
each peak corresponding to an energy level in the atoms. But with a
synchronized infrared pulse present, each electron could pick up or
lose the energy of an infrared photon as it emerged from its atom.
These new possibilities generate two small "sideband" peaks to the
right and left of each main peak in the spectrum of emitted
electrons--one peak with slightly more energy and one with slightly
less energy than the UV-only peak.
See: http://focus.aps.org/story/v18/st10
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