Trapping Ba+ with seven-fold enhanced efficiency utilizing an autoionizing resonance

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, especially when working with long chains of ions or rare isotopes. Here, we compare two different isotope-selective photoionization schemes for loading 138Ba+ 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. Our novel photoionization scheme can be extended to all isotopes of barium. Given that autoionizing resonances exist in every trapped ion species, exploitation of this process is a promising pathway to increase the loading rates for trapped ion computers.