Optics Seminar

Aluminum monofluoride (AlF) is the first spin-singlet molecule to be laser-cooled and captured into a magneto-optical trap (MOT). Its electronic structure is distinct from other laser-cooled molecules, and results in several highly attractive properties: chemical and collisional stability; efficient gas-phase molecular production via a thermochemical reaction; simple optical cycling in any excited rotational level; and a narrow, spin-forbidden, vibrationally diagonal transition from the ground state.In this talk, I will present the latest results from the AlF group in Berlin, where we have now demonstrated a MOT for three different rotational levels of the electronic ground state. I will discuss the experimental challenges and improvements to be made, the prospect of trapping higher rotational levels, and some future plans. Recently, we discovered that AlF can survive collisions with (and therefore thermalise to) room temperature surfaces, despite it having a negligible equilibrium vapour pressure below about 500 K. I will present our first velocity- and angle-resolved measurements of single AlF-surface collision outcomes observed via laser-induced-fluorescence on a camera. We tentatively find that, as shown recently for atomic Yb and Fe, specific polymer-coated surfaces lead to very low sticking probability for AlF. This opens up prospects for cheap, compact and cryogen-free molecular sources for future experiments.