We describe the design, fabrication, and operation of a novel surface-electrode Paul trap that produces a radio-frequency-null along the axis perpendicular to the trap surface. This arrangement enables control of the vertical trapping potential and consequentially the ion-electrode distance via dc-electrodes only. We demonstrate confinement of single 40Ca+ ions at heights between 50μm and 300μm above planar copper-coated aluminium electrodes. We investigate micromotion in the vertical direction and show cooling of both the planar and vertical motional modes into the ground state. This trap architecture provides a platform for precision electric-field noise detection, trapping of vertical ion strings without excess micromotion, and may have applications for scalable quantum computers with surface ion traps.
@article{arxiv.1807.06043,
title = {Surface trap with dc-tunable ion-electrode distance},
author = {Da An and Clemens Matthiesen and Ahmed Abdelrahman and Maya Berlin-Udi and Dylan Gorman and Sönke Möller and Erik Urban and Hartmut Häffner},
journal= {arXiv preprint arXiv:1807.06043},
year = {2018}
}