Photoassociative Production and Detection of Ultracold Polar RbCs Molecules

We have produced ultracold polar RbCs molecules via photoassociation starting from laser-cooled ⁸⁵Rb and ¹³³Cs atoms in a dual−species, forced dark magneto-optical trap. The formed electronically excited RbCs^∗ molecules correlated to the Rb(5S_1/2)+Cs(6P_1/2) dissociation limit are observed by trap loss spectroscopy. Following the decay of these excited RbCs^* molecules, the formed ground state molecules are directly ionized by a two-photon single-color pulse dye laser, which is a new ionization mechanism for ground state RbCs molecules and thence detected by time-of-flight mass spectroscopy.