A novel simplified two-dimensional magneto-optical trap as an intense source of slow cesium atoms

We describe the design and performance of a slow atom source based on a 2D magneto-optical trap (MOT) that uses an innovative simple optical configuration. Metal-coated retro-reflecting prisms replace mirrors and quarter-wave plates so the optical power of the cooling laser beam is recycled. This source has been characterised for three different configurations: with and without transverse magnetic field gradient, and with a pusher beam to obtain a 2D⁺-MOT. The longitudinal velocity is of the order of 25 m•s⁻¹, with a transverse velocity spread ≤1 m•s⁻¹, while the typical atomic flux density obtained is up to 1.3×1014 at •s⁻¹•m⁻² for a cesium vapour pressure of ~4×10⁻⁸ mbar in the source. We use this slow atom beam, instead of cesium vapour, to load a 3D moving optical molasses that feeds a continuous cold atom fountain. We obtain a gain of a factor ~20 in the atomic flux launched by the fountain.