High-resolution photoassociation spectroscopy of ultracold ytterbium atoms by using the intercombination transition

We observed high-resolution photoassociation spectra of laser-cooled ytterbium (Yb) atoms in the spin-forbidden S01-P13 intercombination line. The rovibrational levels in the 0u+ state were measured for red detunings of the photoassociation laser ranging from 2.9MHz to 1.97GHz with respect to the atomic resonance. The rotational splitting of the vibrational levels near the dissociation limit were fully resolved due to the sub-MHz linewidth of the spectra in contrast to previous measurements using the spin-allowed singlet transition. In addition, from a comparison between the spectra of Yb174 and those of Yb176, a d-wave shape resonance for Yb174 is strongly suggested.