Buffer gas cooling and optical cycling of AlF molecules

We have recently identified the aluminum monofluoride (AlF) molecule as an excellent candidate for laser cooling and trapping at high densities, measured the detailed energy level structure of the electronic states relevant for these processes and analyzed possible loss channels from the cycling transition.
AlF is a deeply bound molecule, which can be produced very efficiently in a cryogenic buffer gas molecular beam. It has a strong laser cooling transition in the UV near 228 nm (see Figure 1) that allows to slow the molecules efficiently and trap them in a magneto-optical trap (MOT) with an exceptionally high capture velocity. Once the molecules are trapped, they can be cooled to the recoil limit using a narrow, spin-forbidden transition.
Here, we present experimental results and techniques used to study buffer gas cooling and optical cycling on the main cooling transition and our recent progress towards a dense MOT of AlF molecules.