The physical reality of light-induced states in atoms has remained uncertain, ever since their discovery by Floquet theory. We now show that their existence is confirmed by time-dependent wave packet theory, and should manifest itself experimentally. By applying a realistic pulse to the atomic system, and calculating the energy spectrum of the ionized electrons, we find signals at the energies predicted by Floquet theory for the light-induced states, sometimes with towering intensity. Choosing the initial states such as to connect to the light-induced states via diabatic Floquet paths substantially enhances the yield.

• Received 22 September 1997

DOI:https://doi.org/10.1103/PhysRevLett.80.3479