Optical Feshbach Resonances and Coherent Photoassociation in a Strontium BEC
The divalent electronic structure of alkaline-earth metal atoms such as strontium gives rise to metastable, excited triplet levels and narrow intercombination transitions. These have been exploited for optical clocks, powerful laser cooling techniques that are critical for achieving quantum degeneracy in strontium, and proposals for quantum information architectures and studies of novel magnetism. Metastable excited electronic states also give rise to narrow photoassociation (PA) transitions that differ in many ways from traditional PA with broad, electric-dipole-allowed transitions. In this talk, we will discuss the use of narrow-line PA near the ^1S_0-^3P_1 intercombination transition for two experiments with ^88Sr Bose-Einstein condensates. The first demonstrates the control of condensate collapse and expansion using an optical Feshbach resonance (OFR). The second accesses a regime of coherent PA in which we observe atom-molecule Rabi oscillations and create condensates of excited-state molecules.