A two-state Raman coupler for coherent atom optics

TL;DR

This paper introduces a novel Raman laser system for coherent atom optics that efficiently produces a bright, low-divergence atom laser and enables advanced quantum manipulations like state transfer and interferometry.

Contribution

It presents a new optical design for a two-state Raman coupler capable of generating a high-quality atom laser and facilitating quantum state control in free space.

Findings

Produces a low-divergence, bright atom laser

Enables transfer of photon correlations to atom beams

Acts as an internal state beamsplitter for interferometry

Abstract

We present results on a Raman laser-system that resonantly drives a closed two-photon transition between two levels in different hyperfine ground states of 87Rb. The coupler is based on a novel optical design for producing two phase-coherent optical beams to drive a Raman transition. Operated as an outcoupler, it produces an atom laser in a single internal atomic state, with the lower divergence and increased brightness typical of a Raman outcoupler. Due to the optical nature of the outcoupling, the two-state outcoupler is an ideal candidate for transferring photon correlations onto atom-laser beams. As our laser system couples just two hyperfine ground states, it has also been used as an internal state beamsplitter, taking the next major step towards free space Ramsey interferometry with an atom laser.