Sodium Bose-Einstein Condensates in an Optical Lattice

The phase transition from a superfluid to a Mott insulator has been observed
in a $^{23}$Na Bose-Einstein condensate. A dye laser detuned $\approx 5$nm red
of the Na $3^2$S$ \to 3^2$P$_{1/2}$ transition was used to form the three
dimensional optical lattice. The heating effects of the small detuning as well
as the three-body decay processes constrained the timescale of the experiment.
Certain lattice detunings were found to induce a large loss of atoms. These
loss features were shown to be due to photoassociation of atoms to vibrational
levels in the Na$_2$ $(1) ^3\Sigma_g^+$ state.