Fotoionização atomica em campos de laser intenso

AUTOR(ES)
DATA DE PUBLICAÇÃO

1985

RESUMO

This Thesis focus on a non-perturbative approach to describe a hydrogenic atom behavior in an intense laser field and how it affects the atomic multiphoton ionization rate. The atom in the intense field is described under a formulation which explores an unitary transformation (space translation) to obtain the Lima &Miranda dressed atom effective binding potential. A closed form is then derived for the multiphoton ionization rate, up from the dressed-atom ground state, which takes into account the field induced parametrization of the atomic ionization potential on the laser intensity. Special limits are considered to suit the specific regimen of low or high values of the field intensity describing parameter l (quoted within the context of the present work under the relative designations of "weak" and "strong" fields) by explicitly implementing the corresponding asymptotic behavior of the main function within the closed analytical general expression. In particular, in the weak field limit, in our context, the results that were obtained correctly reproduce the experimentally observed n-photons atomic ionization rate dependence on the laser intensity I, which is well known to be represented by a growth proportional to In. Both the intermediate and strong field regimen were also analyzed. Our theoretical predictions reveal a n-photon atomic ionization rate behavior which eventually subsides, with the rate decreasing for sufficiently strong laser intensities.

ASSUNTO(S)

fotoionização fisica nuclear fotons ions lasers

ACESSO AO ARTIGO

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