An ultracold potassium Rydberg source for experiments in quantum optics and many-body physics*

We report on the development of an apparatus for the study of quantum dynamics of Rydberg atoms of potassium. Samples of Rydberg atoms at 1 mK and varying density are excited in a magneto-optical trap of $10^7$ K-39 atoms. The atoms are excited to Rydberg states in a steps from 4s to 5p and from 5p to $ns$ and $nd$ states using stabilized external-cavity diode lasers at 405 nm and 980 nm. Selective field ionization and detection with microchannel plates provides a platform for spectroscopic measurements in potassium, exploration of multiphoton processes, and experiments on cold atom collisions.