Transport of Multispecies Ion Crystals through a Junction in a Radio-Frequency Paul Trap

We report on the first demonstration of transport of a multispecies ion crystal through a junction in a rf Paul trap. The trap is a two-dimensional surface-electrode trap with an X junction and segmented control electrodes to which time-varying voltages are applied to control the shape and position of potential wells above the trap surface. We transport either a single 171Yb+ ion or a crystal composed of a 138Ba+ ion cotrapped with the 171Yb+ ion to any port of the junction. We characterize the motional excitation by performing multiple round-trips through the junction and back to the initial well position without cooling. The final excitation is then measured using sideband asymmetry. For a single 171Yb+ ion, transport with a 4 m/s average speed induces between 0.013 10.001 and 0.014 10.001 quanta of excitation per round-trip, depending on the exit port. For a Ba-Yb crystal, transport at the same speed induces between 0.013 1 0.001 and 0.030 10.002 quanta per round-trip of excitation to the in-phase axial mode. Excitation in the out-of-phase axial mode ranges from 0.005 10.001 to 0.021 10.001 quanta per round-trip.