A team of physicists has managed to
develop a tractor beam that uses light to pull objects, rather
than push them.
Tomas Cizmar and his fellow researchers at the University of St
Andrews continued research from
Nasa that shows that it's possible for laser beams of a certain
shape to attract objects towards the beam, rather than pushing them
away. Their research was published in
The approach works in both liquids and a vacuum, which is an
improvement on the previous technique used to attract objects with
light. Tractor beam theory, inspired by science fiction, has been
under development since the 60s but this is the first time that
objects have been successfully moved on a microscopic scale.
told the BBC: "The practical applications could be very
great, very exciting. The tractor beam is very selective in the
properties of the particles it acts on, so you could pick up
specific particles in a mixture."
However, it won't work on a larger scale. Cizmar added:
"Unfortunately there is a transfer of energy. On a
microscopic scale that is OK, but on a macro scale it would cause
huge problems. It would result in a
massive amount of heating of an object, like a space shuttle. So
trapping a space ship is out of the question."
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