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arXiv · 1507.07761

Sympathetic cooling and detection of a hot trapped ion by a cold one

M. Guggemos·D. Heinrich·O. A. Herrera-Sancho·R. Blatt·C. F. Roos
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Abstract

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.

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M. Guggemos, D. Heinrich, O. A. Herrera-Sancho, R. Blatt, C. F. Roos. 2015-07-28. Sympathetic cooling and detection of a hot trapped ion by a cold one. https://doi.org/10.1088/1367-2630/17/10/103001

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