Photoassociative Ionization of Ultracold Rubidium in a Magneto-Optic Trap.

D. Leonhardt, J. Weiner

John Douglas Miller

Jing Qi, Yin Hui Huang, H. Kim +3 more

Charles I. Sukenik, H. C. Busch

We have simultaneously confined rubidium and metastable argon in a dual-species magneto-optical trap (MOT). Here a binary mixture of atomic species from different groups of the periodic table have been optically confined at ultracold temperatures. We describe the apparatus and characterize the individual, single species MOTs and the dual-species MOT. Both fluorescence and ion production are monitored. With both species trapped, we observe $\ensuremath{\sim}5\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${}^{85}\mathrm{Rb}$ atoms and $\ensuremath{\sim}2\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${}^{40}{\mathrm{Ar}}^{*}$ atoms. Realization of the dual-species trap opens the way for detailed studies of Penning and associative ionization, photoassociative spectroscopy, and eventually for the production of bound, ultracold RbAr molecules.

D. Leonhardt, J. Weiner

We report the observation of direct, two-color photoassociative ionization (PAI) in collisions between $^{85}\mathrm{Rb}$ atoms optically cooled and confined in a magneto-optical trap. We also measure the resulting ${\mathrm{R}}_{2}^{+}$ ion spectrum and compare it to earlier trap-loss fluoresecence spectra. Unlike PAI in Na, which ionizes principally by collisional autoionization, the ${\mathrm{Rb}}_{2}^{\mathrm{*}}$ intermediate photoionizes directly to ${\mathrm{Rb}}_{2}^{+}$ in a fixed optical field. These observations confirm PAI as a sensitive and broadly applicable spectroscopic tool.

Magnus Albert