# Optical control of atom-ion collisions using a Rydberg state

## TL;DR

This paper introduces a laser-based method to control and shield atom-ion collisions by exciting neutral atoms to Rydberg states, preventing unwanted reactions and enabling precise interaction management.

## Contribution

It proposes a novel optical shielding technique using Rydberg states to control atom-ion collisions, advancing the manipulation of hybrid quantum systems.

## Key findings

- Shielding efficiency depends on laser parameters and collision conditions
- Several Rydberg levels of Na and Rb are suitable for effective shielding
- The method suppresses unwanted chemical reactions in atom-ion systems

## Abstract

We present a method to control collisions between ultracold neutral atoms in the electronic ground state and trapped ions. During the collision, the neutral atom is resonantly excited by a laser to a low-field-seeking Rydberg state, which is repelled by the ion. As the atom is reflected from the ion, it is de-excited back into its electronic ground level. The efficiency of shielding is analyzed as a function of laser frequency and power, initial atom-ion collision energy, and collision angle. The suitability of several Rydberg levels of Na and Rb for shielding is discussed. Useful applications of shielding include the suppression of unwanted chemical reactions between atoms and ions, a prerequisite for controlled atom-ion interactions.