  We have used optical molecular spectroscopy to probe the many-body state of
paired $^6$Li atoms near a broad Feshbach resonance. The optical probe projects
pairs of atoms onto a vibrational level of an excited molecule. The rate of
excitation enables a precise measurement of the closed-channel contribution to
the paired state. This contribution is found to be quite small, supporting the
concept of universality for the description of broad Feshbach resonances. The
dynamics of the excitation provide clear evidence for pairing across the
BEC-BCS crossover, and into the weakly interacting BCS regime.
