Experiments with remote entanglement using single barium ions

Abstract

Barium ions are trapped and Doppler cooled in a linear Paul trap with the goal of demonstrating state initialization, single-qubit operations and detection. Rabi rotations are demonstrated on the 6S1/2 ↔ 6P3/2 transition using single pulses from a mode-locked Ti:Sapphire laser, and some evidence for the same on the more useful 6S1/2] ↔ 6P1/2 transition is shown. With the goal of entangling the polarization mode of emitted photons with the spin state of the ion in the trap in mind, single photon generation and detection ability is demonstrated. A stabilized 1.762 µm laser is used on the 6S1/2 → 5D5/2 transition to demonstrate the ability to state selectively shelve the ion from the ground state to be used as readout. Using the techniques that will enable qubit operations and readout, several quantities of interest in 137Ba+ are measured either for the first time or to higher accuracy than previously achieved.