Creation, Control, and Detection of Rydberg Excitations in Ultracold Strontium*

We benchmark a new apparatus for studying Rydberg physics in ultracold gases by demonstrating the ability to create, control, and detect high-lying excitations. Two-photon transitions via the narrow 5s5p $^{3}$P$_{j}$ intercombination line, unique to alkaline-earth-like atoms, are used to create triplet 5s\textit{nl} Rydberg states with enhanced lifetimes that are inaccessible in alkali systems. These Rydberg excitations have strong, long-range dipolar interactions that can be tuned with principal quantum number and Rydberg fraction. To monitor $n$ and the number of Rydberg atoms created we employ pulsed-field ionization and a microchannel plate detector. This work serves as an important milestone toward realizing many-body phenomena such as roton physics, 3D solitons, supersolidity and long-range spin models.