Atoms interacting with intense, high-frequency laser pulses: Effect of the magnetic-field component on atomic stabilization

Published versio

Analytic Description of the High-Energy Plateau in Harmonic Generation by Atoms: Can the Harmonic Power Increase with Increasing Laser Wavelengths?

A closed-form analytic formula for high-order harmonic generation (HHG) rates for atoms (that generalizes an HHG formula for negative ions [M.V. Frolov et al., J. Phys. B 42, 035601 (2009)]) is used to study laser wavelength scaling of the HHG yield for harmonic energies in the cutoff region of the HHG plateau. We predict increases of the harmonic power for HHG by Ar, Kr, and Xe with increasing wavelength λ over atom-specific intervals of λ in the infrared region, λ ~ (0.8–2.0) μm

High-efficiency generation of attosecond pulses during atomic ionization from excited electronic states

We show that the efficiency of single attosecond pulse generation during atomic ionization by an intense few-optical-cycle laser pulse can be enhanced dramatically when pre-excited electronic states are used. This is due to the slowed-down spreading of the laser-driven free-electron wave packet. We develop an analytical approach to the treatment of the attosecond burst production due to the electron recollision with a parent ion, assuming that the atom is fully ionized during one optical cycle. Our analytical and numerical simulations show that, when a hydrogen atom is ionized from the $2s$-state by an ultrashort pulse of a Ti:sapphire (800\un{nm}) laser, the energy of the generated attosecond pulse is several tens of times higher, its duration is much shorter, and the spectral intensity of radiation in the VUV and soft–X-ray range is several orders of magnitude superior to that in the case of ionization from the ground state. We determine the excited states preferable for experiments using the fundamental or the second harmonic of a Ti:sapphire laser