Most people own their own particle accelerators. In the back of a
television set, electrons are emitted from a cathode and accelerated
and
maneuvered by electric and magnetic fields toward the phosphor screen.
The
same principle of electron acceleration is used in large particle
accelerators, only on a much grander scale. Reducing the size of
accelerators without compromising the need for very high particle energies
is a goal for the next generation of accelerators. Because light is
an
electromagnetic field, schemes are being devised that use light to
accelerate electrons.
Zawadzka et al. demonstrate that shining femtosecond pulses of intense
laser light on a thin film of silver or gold produces an evanescent
light
field that extends from the surface and can accelerate photo-emitted
electrons up to energies approaching 400 electron volts. Although this
energy is quite modest compared with those achieved in traditional
particle
accelerators, calculations show that higher, perhaps even relativistic,
energies may be possible by using longer wavelength light pulses or
by
modulating the film surface to enhance the interaction between the
light
and the electrons. -- ISO
Applied Physics Letters 79, 2130 (2001).