BaF molecules in neon ice: trapping, spectroscopy and optical control of electron spins

Understand

We have trapped BaF molecules in neon ice, and used laser-induced fluorescence spectroscopy to map out optical transitions in the trapped molecules.

• Our measurements show that the neon lattice does not significantly perturb certain optical transitions in the trapped molecules.
• We used one of these transitions to polarize the electron spins, detect spin flips and measure hyperfine transitions in the trapped molecules, entirely using lasers.
• This demonstration with heavy polar molecules opens up new opportunities for precision measurements of beyond-standard-model physics.