Focusing a deterministic single-ion beam

TL;DR

This paper demonstrates deterministic loading and focusing of single 40Ca+ ions into a micron-scale spot using an einzel-lens, achieving high efficiency and significant beam size reduction for potential applications in precise ion placement.

Contribution

We developed a method for deterministic ion loading and demonstrated focusing of single ions with an einzel-lens, reducing beam size by a factor of 12 compared to previous setups.

Findings

Achieved 96.7% efficiency in single-ion loading.

Focused ions to a 4.6 μm spot radius at 257 mm from trap.

Reduced beam divergence and aberrations for precise ion delivery.

Abstract

We focus down an ion beam consisting of single 40Ca+ ions to a spot size of a few mum using an einzel-lens. Starting from a segmented linear Paul trap, we have implemented a procedure which allows us to deterministically load a predetermined number of ions by using the potential shaping capabilities of our segmented ion trap. For single-ion loading, an efficiency of 96.7(7)% has been achieved. These ions are then deterministically extracted out of the trap and focused down to a 1sigma-spot radius of (4.6 \pm 1.3)mum at a distance of 257mm from the trap center. Compared to former measurements without ion optics, the einzel-lens is focusing down the single-ion beam by a factor of 12. Due to the small beam divergence and narrow velocity distribution of our ion source, chromatic and spherical aberration at the einzel-lens is vastly reduced, presenting a promising starting point for focusing single ions on their way to a substrate.