ac Electric Trap for Ground-State Molecules

We here report on the realization of an electrodynamic trap, capable of trapping neutral atoms and molecules in both low-field and high-field seeking states. Confinement in three dimensions is achieved by switching between two electric field configurations that have a saddle point at the center of the trap, i.e., by alternating a focusing and a defocusing force in each direction. The ac trapping of ¹⁵ND₃ molecules is experimentally demonstrated, and the stability of the trap is studied as a function of the switching frequency. A 1 mK sample of ¹⁵ND₃ molecules in the high-field seeking component of the |J,K⟩=|1,1⟩ level, the ground state of para-ammonia, is trapped in a volume of about 1  mm³.