Cristel Chandre, Directeur de Recherche, CNRS

"Capturing photoelectron motion with guiding centers: a Hamiltonian approach"

Abstract: Subjecting atoms or molecules to intense laser fields gives rise to a variety of non-perturbative and highly nonlinear phenomena, such as high-harmonic generation, non-sequential multiple ionization and high-order above-threshold ionization. All these phenomena are based on the key mechanism of attosecond physics, namely the recollision. A recollision is obtained when an electron tunnel-ionizes, freely travels in the laser field, and then upon return to the ionic core, either recombines into an atomic or molecular bound state, or undergoes inelastic or elastic scattering. By experiencing a strong ion-electron interaction, rescattered electrons probe the atomic or molecular structure, providing essential information to imaging atoms and molecules.

I will briefly review some of these applications in strong-field atomic physics, and explain what classical Hamiltonian dynamics has to say about this fundamentally quantum problem. In particular, I will show how reduced Hamiltonian dynamics provides essential insights into electron dynamics in combined Coulomb and laser fields.