An apparatus for ultracold Na-40/41K mixtures toward ground-state molecule production

We present an apparatus for producing ultracold Na- ⁴⁰ K and Na- ⁴¹ K mixtures as a starting point for the formation of fermionic and bosonic ground-state NaK molecules. Sodium and potassium atoms are first loaded into a magneto-optical trap and transferred to an optically plugged magnetic trap, where the mixture undergoes sympathetic cooling via radio-frequency evaporation of Na. A key feature of the apparatus is its ability to switch between loading fermionic ⁴⁰ K and bosonic ⁴¹ K by toggling three acousto-optic modulators. After further sympathetic cooling in an optical dipole trap, we obtain quantum-degenerate Bose–Fermi Na- ⁴⁰ K and Bose–Bose Na- ⁴¹ K mixtures. This apparatus provides a robust starting point for creating ultracold Bose and Fermi gases of ground-state NaK molecules, opening pathways to explore strongly interacting dipolar quantum matter.