Optical Sideband Cooling of Ions in a Penning Trap

Optical sideband cooling is a well-established technique for preparing trapped ions in the ground state of one or more of their motional degrees of freedom. Up to now, this technique has mainly been applied in various types of radiofrequency trap. We show in this paper that the technique is also very effective in a Penning trap, and demonstrate that our trap has an exceptionally low heating rate, due to the large size of the Penning trap electrodes and the absence of large-amplitude radiofrequency fields in the trap.