Efficient 2D molasses cooling of a cesium beam using a blue detuned top-hat beam

We have performed a 2D blue detuned Sisyphus collimation of a cesium beam. Compared to a red detuned Doppler transverse molasses cooling, the setup was found very advantageous because of its faster cooling time allowing a short ( 1 cm ) cooling length and thus finally a denser atomic beam. A fibered laser was developed delivering up to 500 mW fiber coupled optical power. A 2D collimation was realized but this can be done only if the two cooling zones were not overlapping. A beam density enhancement of more than 10 was observed. We found that a simple top-hat beam was more efficient than a Gaussian one. Similar cooling applies to other atom species and leads to a simple method to produce bright collimated atomic beams. Graphical abstract