On trapping geometry for cold atoms in a radio-frequency (rf) dressed potential

We have investigated the atom trapping geometry for trapping of ^87Rb atoms in a radio-frequency (rf) dressed potential generated after superposing a strong linearly polarized rf-field on a static magnetic trap. For this, laser cooled atoms in a magneto-optical trap (MOT) in an ultra-high vacuum (UHV) chamber (pressure ∼ 1.5 × 10^-10 Torr) were trapped in a quadrupole magnetic trap and evaporatively cooled before transferring them to the rf-dressed potential. The experimentally observed hollow shell type atom trapping geometry has been explained by theoretical modelling of the trapping potential.