Microwave multiphoton Rabi oscillations

Abstract
We have made direct observations of microwave multiphoton Rabi oscillations between two Rydberg states in potassium in the strong-radiation-field regime, where a perturbative treatment of the atom-field interaction becomes invalid. The results of measurements of the Rabi oscillation frequency are presented and compared with results calculated using Floquet theory, which predicts a very different field dependence for the Rabi frequency than is typical in the perturbation-theory limit.