Ionization Process of Atoms by Intense Femtosecond Chirped Laser Pulses

Stéphane Laulan, Jérémie Haché, Harouna S. Ba, Samira Barmaki

Laboratoire de Physique Computationnelle et Photonique, Université de Moncton Campus de Shippagan, Shippagan, Canada.

DOI: 10.4236/jmp.2013.410A1002                

Abstract

We numerically investigate the ionization mechanism in a real hydrogen atom under intense fem to second chirped laser pulses. The central carrier frequency of the pulses is chosen to be 6.2 eV (λ = 200 nm), which corresponds to the fourth-harmonic of the Ti:Sapphire laser. Our simulation of the laser-atom interaction consists on numerically solving the three-dimensional time-dependent Schrodinger equation with a spectral method. The unperturbed wave functions and electronic energies of the atomic system were found by using an L² discretization technique based on the expansion of the wave functions on B-spline functions. The presented results of kinetic energy spectra of the emitted electrons show the sensitivity of the ionization process to the chirp parameter. Particular attention is paid to the important role of the excited bound states involved in the ionization paths.

Keywords

Hydrogen Atom; Chirped Laser; Multiphoton Ionization; Population Transfer; Nonperturbative Approach

Conflicts of Interest

The authors declare no conflicts of interest.

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