Observation of a laser-induced resonance in the photoionization spectrum of sodium

Abstract

We report the observation of a structure in the ionization spectrum of sodium, induced by a strong radiation field embedding the 5s $^{2}$${\mathit{S}}_{1/2}$ state into the continuum. The structure, probed by single-photon ionization, shows a marked asymmetry, typical of a laser-induced continuum structure.