High-flux two-dimensional magneto-optical-trap source for cold lithium atoms

We demonstrate a two-dimensional magneto-optical trap (2D MOT) as a beam source for cold ⁶Li atoms. The source is side loaded from an oven operated at temperatures in the range 600T700 K. The performance is analyzed by loading the atoms into a three-dimensional MOT located 220 mm downstream from the source. The maximum recapture rate of ~10⁹ s^-1 is obtained for T≈700 K and results in a total of up to 10¹⁰ trapped atoms. The recaptured fraction is estimated to be 30±10% and limited by beam divergence. The most-probable velocity in the beam (αz) is varied from 18 to 70 m/s by increasing the intensity of a push beam. The source is quite monochromatic with a full width at half maximum velocity spread of 11 m/s at αz=36 m/s, demonstrating that side loading completely eliminates beam contamination by hot vapor from the oven. We identify depletion of the low-velocity tail of the oven flux as the limiting loss mechanism. Our approach is suitable for other atomic species.