# Approaching the Heisenberg limit in an atom laser

## TL;DR

This paper demonstrates that using Raman transitions to produce atom lasers significantly improves beam quality and reduces divergence, approaching the Heisenberg limit, and surpasses traditional RF methods.

## Contribution

It introduces Raman outcoupling as a method to enhance atom laser quality, eliminating lens effects and nearing fundamental quantum limits.

## Key findings

- Raman outcoupling reduces divergence compared to RF methods.
- Beam quality can be improved by over a factor of ten with tight traps.
- Atom lasers can approach the Heisenberg limit, limited mainly by condensate wavefunction shape.

## Abstract

We present experimental and theoretical results showing the improved beam quality and reduced divergence of an atom laser produced by an optical Raman transition, compared to one produced by an RF transition. We show that Raman outcoupling can eliminate the diverging lens effect that the condensate has on the outcoupled atoms. This substantially improves the beam quality of the atom laser, and the improvement may be greater than a factor of ten for experiments with tight trapping potentials. We show that Raman outcoupling can produce atom lasers whose quality is only limited by the wavefunction shape of the condensate that produces them, typically a factor of 1.3 above the Heisenberg limit.