Laser stimulated deexcitation of Rydberg antihydrogen atoms

TL;DR

This paper proposes a laser-based method to rapidly deexcite Rydberg antihydrogen atoms to their ground state, significantly increasing the number of usable atoms for precision experiments.

Contribution

It introduces an optimal mixing technique of high and low angular momentum states with broadband laser stimulation to enhance ground-state antihydrogen production.

Findings

Over 80% of antihydrogen atoms deexcited within 100 ns

Method effective for atoms in n=20-30 states

Requires a 2 J laser at 828 nm

Abstract

Antihydrogen atoms are routinely formed at CERN in a broad range of Rydberg states. Ground-state anti-atoms, those useful for precision measurements, are eventually produced through spontaneous decay. However given the long lifetime of Rydberg states the number of ground-state antihydrogen atoms usable is small, in particular for experiments relying on the production of a beam of antihydrogen atoms. Therefore, it is of high interest to efficiently stimulate the decay in order to retain a higher fraction of ground-state atoms for measurements. We propose a method that optimally mixes the high angular momentum states with low ones enabling to stimulate, using a broadband frequency laser, the deexcitation toward low-lying states, which then spontaneously decay to ground-state. We evaluated the method in realistic antihydrogen experimental conditions. For instance, starting with an initial distribution of atoms within the $n=20-30$ manifolds, as formed through charge exchange mechanism, we show that more than 80\% of antihydrogen atoms will be deexcited to the ground-state within 100 ns using a laser producing 2 J at 828 nm.