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Laser cooling of atoms
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Photon recoil slows atoms toward microkelvin temperatures.
Atoms absorb photons from lasers tuned just below resonance (Doppler effect) and re-emit isotropically, losing momentum, cooling to microkelvin and below. Enables BEC and atomic clocks.
Nobel Prize 1997.
Needs repumping lasers.
In more detail
Laser cooling slows atoms by absorbing photons from opposing lasers, reducing their momentum and temperature. It can cool gases to microkelvin temperatures.
Real-world uses
- Laser cooling makes Bose-Einstein condensates and atomic clocks possible.
- Quantum sensors use cold atoms for precision measurements.
- Physicists use laser cooling to produce ultracold atoms for precision measurements and quantum experiments.
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Frequently asked questions
How does it work?
Atoms absorb photons from one direction and emit them in random directions, slowing down on average.
Who developed it?
Steven Chu, Claude Cohen-Tannoudji and William Phillips won the 1997 Nobel Prize for it.
How does laser cooling work?
Atoms absorb photons from opposing lasers and lose momentum each time, so they slow down and cool.