A quasi-monomode guided atom-laser from an all-optical Bose-Einstein condensate

TL;DR

This paper demonstrates a guided, quasi-monomode atom laser from a spin-purified Bose-Einstein condensate of Rubidium 87, achieved through optical trapping, spin-distillation, and magnetic outcoupling, with low transverse excitations.

Contribution

It introduces an all-optical method to produce a guided, quasi-monomode atom laser in multiple spin states with low transverse excitations.

Findings

Successfully produced a guided atom laser in all spin states of F=1.

Achieved low mean transverse excitation numbers (<n> ~0.65-0.8).

Demonstrated spin purification during BEC evaporation process.

Abstract

We report the achievement of an optically guided and quasi-monomode atom laser, in all spin projection states ($m_F =$ -1, 0 and $+1$) of F=1 in Rubidium 87. The atom laser source is a Bose-Einstein condensate (BEC) in a crossed dipole trap, purified to any one spin projection state by a spin-distillation process applied during the evaporation to BEC. The atom laser is outcoupled by an inhomogenous magnetic field, applied along the waveguide axis. The mean excitation number in the transverse modes is $<n > = 0.65 \pm 0.05$ for $m_F = 0 $ and $<n > = 0.8 \pm 0.3$ for the low field seeker $m_F = -1$.