The aspect ratio W_x/W_y, of the atomic cloud for various expansion times after releasing from the quadrupole magnetic trap and hybrid trap with a holding time of 2 s

Figure 1. The aspect ratio W_x/W_y, of the atomic cloud for various expansion times after releasing from the quadrupole magnetic trap and hybrid trap with a holding time of 2 s. W_x and W_y are the cloud size along the x- and y-axis respectively.

Abstract

We report the rapid accelerated thermalization of potassium (³⁹K) atoms loaded in a magnetic trap, in the presence of a single dipole trap beam. More than an order of magnitude reduction in the thermalization time, to less than a second, is observed with the focused off-resonant beam occupying only 0.01% of the volume of the magnetic trap. A new method for testing for thermalization of relatively hot clouds is devised. The cold atoms are loaded from a magneto-optical trap (MOT) of ³⁹K that has gone through a compressed MOT and sub-Doppler cooling stage. The atoms are prepared in the magnetically stretched |F = 2, m_F = 2〉 state prior to loading into the hybrid trap. We also report a direct loading of ³⁹K atoms, prepared in the state |F = 1〉, into a single beam dipole trap.