Experiments to Control Atom Number and Phase-Space Density in ...

The -1st order of this AOM is coupled into a single-mode polarization-maintaining fiber.
The zeroth order from the Zeeman slower AOM is used for imaging the atoms
at zero magnetic field. This beam is frequency shifted by +40 MHz (IntraAction,
AOM402AF3-10), and coupled into the imaging fibers. Part of this beam is picked
off before the beam is combined with the imaging laser beam path and aligned to a
second 40 MHz AOM (IntraAction, AOM-40). The laser frequency of this beam then
matches the laser frequency of the MOT beams. In the future this beam will become im-
portant to detect the fluorescence signal of single atoms. Throughout the setup shutters
are added to block leakage light from the AOMs that cannot be eliminated otherwise.
Figure 7.35 summarizes the different frequencies of the MOT, repump and Zee-
man slower beams. In this example the frequency offset from the laser lock is 76 MHz,
typical detuning during the MOT loading stage of the experimental sequence. How-
ever, the detuning can be changed to 114 MHz, in which case the MOT and repump
frequencies are exactly on resonance with the atomic transition.
2 2 P 3/2
2 2 S 1/2
Figure 7.35: Frequency detunings of the MOT, repump and Zeeman slower beam. The
spectroscopy laser is locked to the |F = 3/2〉 transition. The detuning due to the
frequency-offset lock is typically 76 MHz during the MOT loading stage of the experimental
sequence. However, the frequency offset can be changed to 114 MHz, in which
case the MOT and repump frequencies are exactly on resonance.
127