S. I. Strakhova

Coherent control with a short-wavelength free-electron laser

Researchers demonstrate correlation of two colours (63.0 and 31.5 nm wavelengths) in a free-electron laser and control photoelectron angular distribution by adjusting phase with 3 attosecond resolution.

Laser-induced resonance trapping in atoms

The coupling of two autoionizing states or of a discrete and an autoionizing state by a strong laser field is studied analytically as well as numerically. The motion of the complex energies is traced as a function of the field strength for different field frequencies and atomic parameters. Most interesting is the critical region where a crossing (or an avoided crossing) of the trajectories occurs. At this critical field intensity, level repulsion in the complex plane occurs. With further increasing intensity, the complex energies move differently. When the resonances are coupled mainly via one common continuum, resonance trapping dominates, i.e. a short- and a long-lived resonance state are formed (level repulsion along the imaginary axis). When, however, the direct coupling dominates, level repulsion along the real axis takes place. Population trapping (defined by a vanishing decay width of one of the states at finite intensity) results from the interplay of the direct coupling of the states and their coupling via the continuum. We also studied the corresponding variation of the cross section for ionization of a laser-driven atom by the probe field.

Fano resonances in the overlapping regime

The line shape of resonances in the overlapping regime is studied by using the eigenvalues and eigenfunctions of the effective Hamiltonian of an open quantum system. A generalized expression

Laser-induced continuum structures and double poles of the S-matrix.

{q}_{k}(E)

Photoelectron spectroscopy of sequential three-photon double ionization of Ar irradiated by EUV free-electron laser pulses

for the Fano parameter of the resonance state k is derived that contains the interaction of the state k with neighbored states

Effects of fullerene confining potential on the ionization of the hydrogen atom by a strong femtosecond VUV pulse

l\ensuremath{\ne}k

Overlapping of Rydberg autoionizing states with a broad resonance in argon

via the continuum. It is energy dependent since the coupling coefficients between the state k and the continuum show a resonancelike behavior at the energies of the neighbored states

Photon and electron ionisation of helium to the n=2 state of He+

l\ensuremath{\ne}k.

Sequential two-photon double ionization of noble gases by circularly polarized XUV radiation

Under certain conditions, the energy dependent

Non-dipole effects in the angular distribution of photoelectrons in sequential two-photon double ionization: argon and neon

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