2015/07/31 by M. Guggemos, D. Heinrich, O. A. Herrera-Sancho +2 · 1 citation
Physics and Astronomy · #quant-ph #physics.atom-ph
paper · pdf · doi:10.1088/1367-2630/17/10/103001
published as New J. Phys. 17, 103001 (2015) · 23 pages, 10 figures, small corrections and extensions in response to referee comments
arxiv created 2015/09/02 · arxiv updated 2015/10/02
We investigate the dynamics of an ion sympathetically cooled by another laser-cooled ion or small ion crystal. To this end, we develop simple models of the cooling dynamics in the limit of weak Coulomb interactions. Experimentally, we create a two-ion crystal of Ca+ and Al+ by photo-ionization of neutral atoms produced by laser ablation. We characterize the velocity distribution of the laser-ablated atoms crossing the trap by time-resolved fluorescence spectroscopy. We observe neutral atom velocities much higher than the ones of thermally heated samples and find as a consequence long sympathethic cooling times before crystallization occurs. Our key result is a new technique for detecting the loading of an initially hot ion with energy in the eV range by monitoring the motional state of a Doppler-cooled ion already present in the trap. This technique not only detects the ion but also provides information about dynamics of the sympathetic cooling process.