High-intensity and ground-state influence on photoassociation line shapes of 88Sr

The photoassociation probabilities of a sample of ultracold strontium atoms at 1 μK, are analyzed under the systematically varied conditions of frequency detuning and laser intensities, and for different dispersion values of the ground state potential curve. At low intensities, different values of dispersion coefficient of the ground state potential can give the same line shape, but at high enough intensity this multiplicity is lifted and the revealed periodic behavior is broken. The intensity of the laser becomes a control knob in the laboratory and it can be used to make better determinations of the ground state potential energy curve.