Observation of Bose condensation
Direct and non-destructive observation of the formation of a Bose condensate by dispersive light scattering (phase-contrast imaging) at MIT. The intensity of scattered light is shown as a function of position in the trap, which is proportional to the column density of atoms along the line-of-sight.
The image on the left shows the cloud cooled to just above the BEC transition temperature, and the distribution of atoms is almost classical. As the temperature is lowered through the phase transition a sharp peak of atoms begins to appear at the trap centre (middle), and further cooling increases the condensate fraction to almost 100% (right).