Optical Feshbach resonances

Optical tuning of the scattering length in a Bose-Einstein condensate as predicted by Fedichev et al is demonstrated. Atoms in a ⁸⁷rubidium condensate were exposed to laser light tuned close to the transition frequency to a molecular state. The optical coupling of the atomic scattering state to the molecular state gives rise to what is called an optical Feshbach resonance. It is shown that the optical Feshbach resonance can be induced via one or two photon transitions.