Observation of Rydberg transitions induced by optical core dressing

Abstract
We study experimentally the behaviour of magnesium Rydberg series converging to the and ion states, coupled by a strong () light field that is resonant with the transition between the ion states ( nm). This strong-field version of isolated-core excitation leads to modifications in the photoionization spectrum of the bound Rydberg series and to transitions between bound Rydberg states when the Rabi frequency associated with the core transition becomes larger than the Rydberg spacing.