We report on experiments with a microfabricated surface trap designed for trapping a chain of ions in a ring. Uniform ion separation over most of the ring is achieved with a rotationally symmetric design and by measuring and suppressing undesired electric fields. After minimizing these fields the ions are confined primarily by an rf trapping pseudo-potential and their mutual Coulomb repulsion. The ring-shaped crystal consists of approximately 400 Ca+ ions with an estimated average separation of 9 μm.
@article{arxiv.1501.06554,
title = {Assembling a ring-shaped crystal in a microfabricated surface ion trap},
author = {Boyan Tabakov and Francisco Benito and Matthew Blain and Craig R. Clark and Susan Clark and Raymond A. Haltli and Peter Maunz and Jonathan D. Sterk and Chris Tigges and Daniel Stick},
journal= {arXiv preprint arXiv:1501.06554},
year = {2015}
}