Theory of Multiphoton Ionization of Atoms

Attosecond electron pulses from interference of above-threshold de Broglie waves

“…The concept of the laser-induced oscillating double-layer potential (energy), outlined above has been first introduced in our earlier study (Varró & Ehlotzky, 1998), in order to explain a surprising outcome from one of our experiments (Farkas & Tóth, 1990), namely, the appearance of very large ($600 eV) energy photoelectrons induced by Nd:Glass laser radiation (hn ¼ 1.17 eV) at moderate intensities of some 10 GW/cm 2 . The main problem there was that the very large nominal order of the photon absorption processes corresponding to the experimental results (n ¼ 5 -600) could not have been deduced even from the usual non-perturbative approach based on Gordon -Volkov states (Kylstra et al, 2001), since the intensity parameter m ¼ eF 0 /mcv was very small, on the order of 10 24 in that case. That time we have realized that instead of m, another basic dimensionless parameter "a" appears in the analysis in a natural way, when we introduce the interaction with the double-layer potential, which builds up due to the coherent collective excitation of all the electrons within the skin depth.…”

Intensity Effects and Absolute Phase Effects in Nonlinear Laser-Matter Interactions

“…Our original model belongs to a wider class Floquet-type analyses (see e.g. Kylstra (2001)), and considers the inelastic electron scattering on the oscillating double-layer potential generated by the incoming laser field at the metal surface. The model has already been succesfully used to interpret the experimental results on very high order surface photoelectric effect in the near infrared (Farkas & Tóth (1990)) and in the far infrared regime (Farkas et al, 1998).…”