Magneto-optical trapping of Fermionic potassium atoms

Abstract

We have trapped ${}^{40}\mathrm{K}$ in a vapor-cell magneto-optical trap starting from a natural abundance sample. This rare, weakly radioactive atom is a fermion. The number of trapped atoms is approximately 8000, with a density of $\sim {10}^8$ atoms/${\mathrm{cm}}^3$. Contrary to what is observed for the other isotopes of potassium, our data indicate that temperatures lower than the Doppler-cooling limit can be reached for ${}^{40}\mathrm{K}$. We discuss the interest of these results in view of possible experiments to study a degenerate Fermi gas.