Electric field compensation and sensing with a single ion in a planar trap

We use a single ion as a movable electric field sensor with accuracies on the order of a few V/m. For this, we compensate undesired static electric fields in a planar radio frequency trap and characterize the static field and its curvature over an extended region along the trap axis. We observe a strong buildup of stray charges around the loading region on the trap resulting in an electric field of up to 1.3 kV/m at the ion position. We also find that the profile of the stray field remains constant over a time span of a few months. (C) 2011 American Institute of Physics. [doi:10.1063/1.3665647]