Atomic fountain of laser-cooled Yb atoms for precision measurements

This is the authors' abstract. We don't add key points for this paper.

We demonstrate launching of laser-cooled Yb atoms in a cold atomic fountain. Atoms in a collimated thermal beam are first cooled and captured in a magneto-optical trap (MOT) operating on the strongly allowed ¹S₀→¹P₁ transition at 399 nm (blue line). They are then transferred to a MOT on the weakly allowed ¹S₀→³P₁ transition at 556 nm (green line). Cold atoms from the green MOT are launched against gravity at a velocity of around 2.5 m/s using a pair of green beams. We trap more than 10⁷ atoms in the blue MOT and transfer up to $70%$ into the green MOT. The temperature for the odd isotope ¹⁷¹Yb is ~1 mK in the blue MOT, and reduces by a factor of 40 in the green MOT.