Optical-Optical Double Resonance Photoassociative Spectroscopy of Ultracold39K Atoms near Highly Excited Asymptotes

Abstract

We report the first observation of optical-optical double resonance photoassociative spectroscopy of ultracold ${}^{39}$K atoms near the highly excited ${}_{}{}^{39}{}_{}{}^{}K\left(4s\right)+{}_{}{}^{39}{}_{}{}^{}K(4d,5d,6d,6s,7s)$ asymptotes in a high density magneto-optical trap. Using the $v^{\prime }=0\mathrm{}$ level of the $0_g^{-}$ “pure long-range” state (a localized long-range Franck-Condon window) as the intermediate state, we observe simple and assignable rovibrational progressions dissociating to these asymptotes. The dominant long-range potential constants are determined. Line broadening, presumably due to autoionization, and rotational excitations due to strong field effects are observed.