Trapping $\mathbf{Ba}^+$ with Seven-fold Enhanced Efficiency Utilizing an Autoionizing Resonance

TL;DR

This paper demonstrates that using an autoionizing resonance in two-step photoionization significantly increases the efficiency of loading Ba+ ions, which can enhance the scalability of trapped ion quantum computers.

Contribution

The study introduces a novel autoionizing resonance technique for ion loading, achieving nearly tenfold increase in efficiency with minimal additional technology.

Findings

Autoionizing resonance increases loading rate nearly tenfold.

Only a diode laser needed for implementation.

Technique applicable to all barium isotopes and species used in quantum processing.

Abstract

Trapped ions have emerged as a front runner in quantum information processing due to their identical nature, all-to-all connectivity, and high fidelity quantum operations. As current trapped ion technologies are scaled, it will be important to improve the efficiency of loading ions, which is currently the slowest process in operating a trapped ion quantum computer. Here, we compare two isotope-selective photoionization schemes for loading $^{138}\mathrm{Ba}^+$ ions. We show that a two-step photoionization scheme ending in an autoionizing transition increases the ion loading rate nearly an order of magnitude compared to an established technique which does not excite an autoionizing state. The only additional technology required to implement the autoionizing transition is a commercial diode laser. Our technique can be extended to all isotopes of barium, and autoionizing resonances exist in every species currently used for trapped ion quantum processing, making this a promising technique to drastically increase the loading rates for all trapped ion computers.