Towards single site addressing of ions in a Penning ion trap

General quantum information processing (QIP) with trapped-ion crystals requires implementing programmable rotations on individual ion qubits. We describe recent experimental progress towards this goal of single site addressing of single-plane arrays of several hundred ions generated in a Penning ion trap. Penning traps utilize a combination of static electric and magnetic fields to confine ions. This induces an overall rotation of the crystal that makes individual addressing of the ions challenging (rotation frequency ~180 kHz). We are implementing a deformable mirror (DM) to generate wavefront deformations in a laser beam whose waist is large compared to the ion crystal radius. This altered beam is interfered with another co-propagating beam, resulting in an AC Stark shift intensity pattern. Setting the detuning between the two beams to multiples of the rotation frequency allows the creation of programmable AC Stark shift patterns which are stationary in the rotating frame of the ion crystal and can thus target single ions assuming sufficiently fine control over the DM surface.

We utilize a DM with enough actuators to allow addressing of subgroups consisting of 5 or more ions in a crystal of ~100 ions and have designed an imaging pathway which will image the surface of the DM onto the ions. Tests of the deformable mirror utilizing an interferometer setup and a high numerical aperture lens indicate that this scheme can enable single site resolution using a DM with more actuators.