Magnetoassociation of a Feshbach molecule and spin-orbit interaction between the ground and electronically excited states

By preparing a cold-atom ensemble of mixtures of the ground S-1(0) and metastable P-3(2) states of ytterbium atoms Yb-171, we successfully associate a Feshbach molecule Yb-171(2) with one Yb-171 atom in its electronically excited state and another one in the ground state, by sweeping a magnetic field across a Feshbach resonance. The atom-molecule conversion efficiency reaches about 50%, confirmed by a separate image of atoms and molecules with a Stern-Gerlach effect and an atom loss measurement. In addition, we successfully implement a spin-orbit coupling with a one-photon process between the P-3(2) (pseudo-spin-up) and ground S-1(0) (pseudo-spin-down) states of a Yb atom. As a benchmark, we observe a spin-momentum locking behavior at a large Rabi frequency. The achieved successful production of Feshbach molecules, along with the implementation of spin-orbital coupling between the S-1(0) and P-3(2) states, provides an important step towards the study of a topological superfluid.