(a) Thermal relaxation in a hybrid trap, (b), (c) and (d) shows the thermal relaxation in magnetic trap after the dipole trap has been kept on for 1 s, 500 ms and 200 ms respectively, (e) shows the thermal relaxation in the magnetic quadrupole trap only

Figure 2. (a) Thermal relaxation in a hybrid trap, (b), (c) and (d) shows the thermal relaxation in magnetic trap after the dipole trap has been kept on for 1 s, 500 ms and 200 ms respectively, (e) shows the thermal relaxation in the magnetic quadrupole trap only.

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.