Characterization of fast ion transport via position-dependent optical deshelving

Ion transport is an essential operation in some models of quantum information processing, where fast ion shuttling with minimal motional excitation is necessary for efficient high-fidelity quantum logic. While fast and cold ion shuttling has been demonstrated, the dynamics and specific trajectory of an ion during diabatic transport have not been studied in detail. Here we describe a position-dependent optical deshelving technique useful for sampling an ion's position throughout its trajectory and we demonstrate the technique on fast linear transport of a 40Ca+ ion in a surface-electrode ion trap. At high speed, the trap's electrode filters strongly distort the transport potential waveform. With this technique, we observe deviations from the intended constant-velocity (100-m/s) transport: We measure an average speed of 82(2) m/s and a peak speed of 251(6) m/s over a distance of 120 mu m.