From multimode to monomode guided atom lasers: an entropic analysis

TL;DR

This paper demonstrates precise control over guided atom laser modes through entropy analysis, achieving nearly pure monomode states and enabling spinor and polarization tailoring.

Contribution

It introduces an entropic approach to control mode populations in guided atom lasers, achieving high purity and new polarization capabilities.

Findings

Entropy per particle of GAL matches that of the BEC source.

Achieved 85% in the ground state for monomode GAL.

Optical outcoupling enables spinor and polarization control.

Abstract

We have experimentally demonstrated a high level of control of the mode populations of guided atom lasers (GALs) by showing that the entropy per particle of an optically GAL, and the one of the trapped Bose Einstein condensate (BEC) from which it has been produced are the same. The BEC is prepared in a crossed beam optical dipole trap. We have achieved isentropic outcoupling for both magnetic and optical schemes. We can prepare GAL in a nearly pure monomode regime (85 % in the ground state). Furthermore, optical outcoupling enables the production of spinor guided atom lasers and opens the possibility to tailor their polarization.