Localized addressing of large trapped ion crystals in a Penning trap using a spatial light modulator

Penning traps provide a useful platform for expanding trapped ion applications to much larger qubit numbers than typically accessible in RF Paul traps. To date, most work with large numbers of ions in Penning traps has relied on global control to perform quantum sensing and simulation experiments. Universal quantum control, however, also requires individual qubit addressing, which is challenging due to the rapid rotation of the ion crystal. Here, we demonstrate a technique to address sections of a crystal without the requirement for tightly focused beams. We utilize a spatial light modulator (SLM), which has high reflectivity even in the UV, to imprint spatial phase variations on a laser beam. By interfering this beam with a second uniform beam and adjusting the detuning between the beams, azimuthally asymmetric AC Stark shift (ACSS) patterns that are stationary in the crystal’s rotating frame are applied [1]. The SLM also enables imprinting of azimuthally symmetric patterns, which are useful for thermometry of the in-plane ion motion. With ≳100 Be⁺ ions, we demonstrate high-fidelity ACSS pattern imprinting, which serves as a proof-of-principle that localized addressing of rotating crystals is possible with only a large, stationary beam. Furthermore, the simple patterns we show here can be combined to create more complex patterns, such as those required for individual addressing. Our current capabilities are largely limited by the number of actuators on the SLM, so the high fidelities we achieve here establish a clear path towards individual addressing in a Penning trap.

[1] A. Polloreno, et al., Phys. Rev. Res. 4, 033076 (2022).