Magneto-optical trap for thulium atoms

Abstract

Thulium atoms are trapped in a magneto-optical trap using a strong transition at $410$ nm with a small branching ratio. We trap up to $7\ifmmode\times\else\texttimes\fi{}{10}^{4}$ atoms at a temperature of $0.8(2)$ mK after deceleration in a $40$-cm-long Zeeman slower. Optical leaks from the cooling cycle influence the lifetime of atoms in the magneto-optical trap which varies between $0.3$ and $1.5$ s in our experiments. The lower limit for the leaking rate from the upper cooling level is measured to be $22(6)$ ${\mathrm{s}}^{\ensuremath{-}1}$. The repumping laser transferring the atomic population out of the $F=3$ hyperfine ground-state sublevel gives a $30%$ increase for the lifetime and the number of atoms in the trap.