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April 15, 2005

Class Revew — 4/14

Class,

Make sure that you read this entire entry -- there is information on the talks you will be giving!

For your talks, plan on 13 minutes plus 5 minutes for questions. Do not plan on using the board -- instead, use Powerpoint or transparencies. I can provide you with transparencies of various kinds. I can also supply a laptop for use during your talk. Let me know in advance if you will be using Powerpoint.

I need to clean up the lecture notes on Sysiphus cooling before I post them. There will be no pre-flight for Monday, but I will post reading material on resonance fluorescence for those of you who are interested.

Yesterday in class we talked about:
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  1. The Doppler limit, which is the limiting temperature (about 150 microK) for simple Doppler cooling. It comes from the competition between Doppler cooling and recoil heating.

  2. So-called Sysiphus cooling (or polarization gradient cooling, or sub-Doppler cooling, or...). This is a tricky cooling process which relies on optical pumping among hyperfine ground states as an atom moves through the optical potentials produced by overlapping laser beams. Sysiphus cooling can produce a very large force for low-velocity atoms, which lets us cool to lower temperatures (few-10 microK)

  3. Magneto-optic traps (MOTs). MOTs are the workhorses of atomic physics -- they let us trap and cool billions of atoms from a room temperature vapor. A MOT is an optical molasses with an added quadrupole magnetic field. The magnetic field adds a position dependence to the optical force using the Zeeman effect. The overall trap is characterized by a spring-constant and a damping rate.

Cheers,

Brian

Posted by Brian at April 15, 2005 10:20 AM

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