A dense gas of laser-cooled atoms for hybrid atom-ion trapping

Abstract

We describe the realization of a dark spontaneous-force trap of rubidium atoms. The atoms are loaded from a beam provided by a two-dimensional magnetooptical trap yielding a capture efficiency of 75%. The dense and cold atomic sample is characterized by saturated absorption imaging. Up to 10 9 atoms are captured with a loading rate of 3 × 10 9 atoms/s into a cloud at a temperature of 250 μK with the density exceeding 10 11 atoms/cm 3 . Under steady-state conditions, more than 90% of the atoms can be prepared into the absolute atomic ground state, which provides favorable conditions for the investigation of sympathetic cooling of ions in a hybrid atom-ion trap.