Microscopy with a Deterministic Single Ion Source

TL;DR

This paper presents a novel microscopy technique using a deterministic single ion source for transmission imaging, achieving nanometer resolution and high signal-to-noise ratio, with applications demonstrated in precise position measurements.

Contribution

The work introduces a deterministic laser-cooled ion source for microscopy, enhancing resolution and signal quality over traditional methods, and employs Bayesian optimization for improved spatial information.

Findings

Achieved 5.8 nm focusing resolution.

Reduced dark counts by six orders of magnitude.

Determined hole position with 2.7 nm accuracy using 579 ions.

Abstract

We realize a single particle microscope by using deterministically extracted laser cooled $^{40}$Ca$^+$ ions from a Paul trap as probe particles for transmission imaging. We demonstrate focusing of the ions with a resolution of 5.8$\;\pm\;$1.0$\,$nm and a minimum two-sample deviation of the beam position of 1.5$\,$nm in the focal plane. The deterministic source, even when used in combination with an imperfect detector, gives rise to much higher signal to noise ratios as compared with conventional Poissonian sources. Gating of the detector signal by the extraction event suppresses dark counts by 6 orders of magnitude. We implement a Bayes experimental design approach to microscopy in order to maximize the gain in spatial information. We demonstrate this method by determining the position of a 1$\,\mu$m circular hole structure to an accuracy of 2.7$\,$nm using only 579 probe particles.