Photoassociation of a Bose-Einstein Condensate near a Feshbach Resonance
We measure the effect of a magnetic Feshbach resonance (FR) on the rate and light-induced frequency shift of a photoassociation resonance in ultracold Li7. The photoassociation-induced loss-rate coefficient Kp depends strongly on magnetic field, varying by more than a factor of 10?4 for fields near the FR. At sufficiently high laser intensities, Kp for a thermal gas decreases with increasing intensity, while saturation is observed for the first time in a Bose-Einstein condensate. The frequency shift is also strongly field dependent and exhibits an anomalous blueshift for fields just below the FR.