Stimulated emission in multiphoton excitation of an atom above the ionization limit
Korolev F.A., Znamenskii N.V., Odintsov V.I.
Powerful stimulated emission in the infrared (IR) region of the spectrum was observed following three-photon excitation of a rubidium atom above the ionization limit. The phenomenon has a clearly pronounced resonant character and may be connected with the resonant ionization of the atom.