Highly collimated source of cold Rubidium atoms from a two dimensional magneto-optical trap

TL;DR

This paper demonstrates a method to produce a highly collimated, dense, and cold atomic beam of Rubidium using a Laguerre-Gaussian laser mode in a 2D magneto-optical trap, optimizing parameters to minimize heating.

Contribution

It introduces a novel collimation technique with Laguerre-Gaussian beams to enhance atomic beam quality in a 2D-MOT, reducing divergence and increasing density.

Findings

Atomic beam diameter reduced to 1 mm

Divergence decreased from 40 to 3 mrad

Atomic density increased by a factor of 200

Abstract

Using a blue detuned laser shaped in a Laguerre-Gaussian donut mode we highly collimate the output of a two dimensional magneto-optical trap. The resulting atomic beam has a 1 mm diameter, its divergence is reduced from 40 down to 3 mrad and the atomic density is increased by a factor of 200. The collimation effect has been studied versus the order of the Laguerre-Gaussian mode (up to 10) and the laser atom frequency detuning (2 to 120 GHz). The 2D-colli-MOT study allows us to determine the best conditions which minimize the atom heating due to residual light absorption and optimize the collimation effect. The 2D-colli MOT could provide a new tool to fill a 3D-MOT using lasers with millimeter range diameters and thus sparing the laser power.