Towards single site addressing of ions in a Penning trap

We describe recent experimental progress towards single site addressing of single plane arrays of several hundred ions generated in a Penning trap. Penning traps utilize a combination of static electric and magnetic fields to confine ions, however 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 the generation of an AC Stark shift intensity pattern. Setting the difference frequency of the two beams to multiples of the rotation frequency allows the creation of programable AC Stark shifts that are stationary in the rotating frame of the ion crystal and can thus target single ions with a fine enough control over the DM surface [1].

We utilize a DM with sufficient actuators to allow targeting 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 set-up and a high numerical aperture lens indicate that this scheme can enable single site resolution using a DM with more actuators.



[1] Polloreno, A. M., Rey, A. M., & Bollinger, J. J. (2022). Individual qubit addressing of rotating ion crystals in a Penning trap. Physical Review Research, 4(3), 033076.