Stabilization: The experiment

Fermi's Golden Rule (FGR) states that the ionization rate of an atom increases proportionally to the light intensity, provide that ionization with a single photon is possible. Pont and Gavrila were the first to show that at high intensities this relation breaks down in a counter-intuitive way: the ionization rate of the atom decreases dramatically with intensity above a certain critical intensity Icr. This effect has become known as stabilization. To date there have been proposed a number of physically distinct mechanisms that are collectively known as stabilization. They all have in common that a fraction of the atoms retains its electrons after exposure to a laser pulse, even if the amplitude or duration of the pulse is increased further.