Jonas Rodewald (London): Optical trapping of laser cooled molecules, ultracold collisions and molecular clock making

The application of laser cooling methods to molecules has seen rapid progress in recent time, opening up new avenues towards precision tests of fundamental physics, quantum simulation and studies of ultra-cold chemistry. At Imperial College’s Centre for Cold Matter in London, we are pursuing all these directions with our molecule of choice, Calcium Monofluoride. In this talk, I will discuss the methods we developed for trapping, laser cooling and coherent control of these particles. I will show our latest results on loading the molecules into an optical dipole trap as well as a 1D optical lattice. Our setup allows us to trap the molecules in the same optical trap as a sample of Rb⁸⁷ atoms and study collisions between the two species. I will present our progress towards observing thermalization and sympathetic cooling of the molecules to high phase space densities. In parallel, we are setting up a molecular lattice clock to test for time-variation of the proton-to-electron mass ratio. The clock will be based on the fundamental vibrational transition in Calcium Monofluoride at a wavelength of around 17μm. The transition is expected to have a sub-Hz linewidth and be largely insensitive to systematic DC Stark or Zeeman shifts. I will present the progress we are making in the spectroscopy of the clock transition as well as building the clock laser system. .