Precision measurements with BaF molecules


In this project, we use laser-cooled diatomic molecules as sensors for fundamental physics.

Over the centuries, the main driving force of physics has been the search for the fundamental laws describing the workings of our universe. Key tools to achieve progress in this direction have recently been increasingly powerful, yet also increasingly complex and expensive particle accelerators and other large-scale facilities. An alternative approach in the search for new physics are compact precision experiments on much smaller energy scales. By realizing precisely controlled molecular quantum systems, measurements with extraordinary precision become possible, opening up a complementary new window into the world of fundamental physics.

Our current molecule of choice is barium monofluoride (BaF). BaF is very heavy, which yields a high sensitivity to many fundamental effects that we want to investigate. We use buffer gas cooling and laser cooling to generate a cold and intense beam of BaF molecules for our measurements. 

Recent publications:


  • Laser cooling of barium monofluoride molecules using synthesized optical spectra
    M. Rockenhäuser*, F. Kogel*, T. Garg, S. A. Morales-Ramírez, and T. Langen
    arxiv:2405.09427 (2024)
  • Absorption spectroscopy for laser cooling and high-fidelity detection of barium monofluoride molecules
    M. Rockenhäuser, F. Kogel, E. Pultinevicius, and T. Langen
    Phys. Rev. A 108, 062812 (2023), arxiv:2307.08312


Laser cooling of BaF molecules


Experimental Setup