Barium Autoionization for Efficient Ion Trap Loading

TL;DR

This paper investigates autoionizing resonances in neutral barium to enhance ion trap loading efficiency, combining theory and experiments, and identifies a broad transition at 531 nm that significantly improves loading rates.

Contribution

It introduces a new broad transition at 531 nm for barium ion loading, achieving an order-of-magnitude efficiency increase over previous methods.

Findings

Large theoretical autoionizing cross sections predicted.

Doppler broadening reduces effective cross sections in practice.

531 nm transition significantly improves trap loading efficiency.

Abstract

We report a theoretical and experimental investigation of autoionizing resonances from the $5d6p\,{}^3\mathrm{D}_1^o$ manifold in neutral barium for efficient loading of ion traps. Our calculations predict large resonant cross sections for many narrow autoionizing resonances, but we find experimentally that for most of these, Doppler broadening during trap loading depresses the effective cross sections that can be achieved in practice. We identify and demonstrate a strong, broad transition at $531\,\mathrm{nm}$, and show that it furnishes an order-of-magnitude increase in trap loading efficiency compared to other demonstrated resonances.