Laser Cooling and Trapping, Part 1
Doesn't shining light on something make it hotter, not
colder?
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Shining light on your hand makes it get hotter because the light
is absorbed and turns into heat. The trick to
making atoms colder is to make the light bounce off of them.In fact,
it bounces off with more energy than when it hits the atoms.
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That sounds like quite a trick.
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It is. It took physicists quite a while to figure out how to
do it. [Click here
to find out more about laser cooling and the winner of the 1997 Nobel Prize for
Physics.] You start with the idea that laser light comes
in a stream of photons . These photons are
very light, so to speak. Compared to an atom, they are like ping-pong
balls compared to a bowling ball. But in just the same way you can
push a bowling ball around if you shoot a big enough stream of
ping-pong balls at it, you can push atoms around by bouncing laser
light off them. Try to adjust the laser power and laser position
to slow down the atoms.
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6th
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