Transport of multispecies ion crystals through a junction in an RF Paul trap

Abstract

We report on the first demonstration of transport of a multispecies ion crystal through a junction in an 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 ${}^{171}$Yb${}^{+}$ ion or a crystal composed of a ${}^{138}$Ba${}^{+}$ ion cotrapped with the ${}^{171}$Yb${}^{+}$ 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 ${}^{171}$Yb${}^{+}$ ion, transport with a $4m/s$ average speed induces between $0.013\pm 0.001$ and $0.014\pm 0.001$ quanta of excitation per round trip, depending on the exit port. For a Ba-Yb crystal, transport at the same speed induces between $0.013\pm 0.001$ and $0.030\pm 0.002$ quanta per round trip of excitation to the axial center of mass mode. Excitation in the axial stretch mode ranges from $0.005\pm 0.001$ to $0.021\pm 0.001$ quanta per round trip.

6 pages, 4 figures, plus 2 page supplement