Isotope-Selective Laser Ablation Ion-Trap Loading of $\mathbf{^{137}\mathrm{Ba}^+}$ using a $\mathbf{\mathrm{BaCl}_2}$ Target

TL;DR

This paper demonstrates isotope-selective laser ablation of barium chloride targets combined with two-step photoionization to efficiently and selectively load $^{137} ext{Ba}^+$ ions into a trap, offering advantages over traditional methods.

Contribution

It introduces a novel method combining laser ablation of BaCl₂ with two-step photoionization for selective loading of $^{137} ext{Ba}^+$ ions into traps.

Findings

Successful trapping of $^{137} ext{Ba}^+$ ions with enhanced isotope selectivity.

Characterization of ablation regimes and plume dynamics for BaCl₂ targets.

Laser ablation provides a fast, low-heat, and efficient loading technique for barium ions.

Abstract

The $^{133}\mathrm{Ba}^+$ ion is a promising candidate as a high-fidelity qubit, and the $^{137}\mathrm{Ba}^+$ isotope is promising as a high-fidelity qudit ($d>2$). Barium metal is very reactive, and $^{133}\mathrm{Ba}^+$ is radioactive and can only be sourced in small quantities, so the most commonly used loading method, oven heating, is less suited for barium, and is currently not possible for $^{133}\mathrm{Ba}^+$.Pulsed laser ablation solves both of these problems by utilizing compound barium sources, while also giving some distinct advantages, such as fast loading, less displaced material, and lower heat load near the ion trap. Because of the relatively low abundances of the isotopes of interest, a two-step photoionization technique is used, which gives us the ability to selectively load isotopes. Characterization of the ablation process for our $\mathrm{BaCl}_2$ targets are presented, including observation of neutral and ion ablation-fluence regimes, preparation/conditioning and lifetimes of ablation spots, and plume velocity distributions.We show that using laser ablation on $\mathrm{BaCl}_2$ salt targets with a two-step photoionization method, we can produce and trap barium ions reliably. Further, we demonstrate that with our photoionization method, we can trap $^{137}\mathrm{Ba}^+$ with an enhanced selectivity compared to its natural abundance.