Observing the Profile of an Atom Laser Beam

TL;DR

This paper investigates the transverse momentum distribution of an atom laser from a Bose-Einstein condensate, revealing the influence of mean-field potential and demonstrating high-resolution measurement techniques.

Contribution

It provides the first detailed measurement of the atom laser's transverse momentum profile and compares experimental data with 3D simulations, highlighting the role of mean-field effects.

Findings

Transverse momentum distribution is shaped by the condensate's mean-field potential.

Achieved a momentum resolution of 1/60 of a photon recoil.

Experimental data agrees well with 3D simulation results.

Abstract

We report on an investigation of the beam profile of an atom laser extracted from a magnetically trapped $^{87}$Rb Bose-Einstein condensate. The transverse momentum distribution is magnified by a curved mirror for matter waves and a momentum resolution of 1/60 of a photon recoil is obtained. We find the transverse momentum distribution to be determined by the mean-field potential of the residing condensate, which leads to a non-smooth transverse density distribution. Our experimental data are compared with a full 3D simulation of the output coupling process and we find good agreement.