Single-Photon Atomic Cooling - Raizen Lab - The University of ...

energy increase due to the recoil from the spontaneous decay process equals
the energy removed from the Sisyphus effect then equilibrium is reached, this
occurs at the recoil temperature.
Tr = 2 k 2
mkB
The Sisyphus effect typically results in atomic samples being cooled to a few
times the recoil temperature, which for 87 Rb is 362.96 nK.
2.5.2.4 Magneto-Optical Trap
As discussed in Sec. 2.5.2.2, spontaneous light forces can be used to
confine atoms in velocity space if beams are arranged appropriately and tuned
slightly below the atomic resonance frequency. Unfortunately, optical mo-
lasses does not confine atoms spatially. However, with the correct choice of
beam polarizations and the addition of a magnetic field gradient, a hybrid
magneto-optical trap (MOT) can be formed which both cools and confines
atomic samples. The idea of this extremely useful trap was proposed in 1986
[71] and demonstrated the following year [10]. Since then MOTs have become
the most widely used cold atom trap. In fact, our experiment uses two separate
MOTs to operate, as discussed in Ch. 3.
Figure 2.10 shows the typical geometry of a MOT. Just like the arrange-
ment in optical molasses, the MOT uses three pairs of counter-propagating
beams tuned slightly below the atomic resonance frequency. In this case how-
ever, the beams must be chosen to have opposite circular polarization for
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