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MPINP:
Research group K. Z. Hatsagortsyan – Division C. H. Keitel
Abstract:
The thesis is devoted to the analytical and numerical studies of high-order harmonic
generation and super-intense single attosecond pulse emission via ultra-relativistic laserplasma
interaction. In the ultra-relativistic regime, the laser radiation pressure induces
plasma ion motion through the so called hole-boring effect, resulting in frequency widening
of the harmonic spectra. This widening, analyzed analytically and validated by
particle-in-cell simulations, produces a quasi-continuous frequency spectrum, a prerequisite
for generating an intense single attosecond pulse. Based on the results and physical
considerations, parameter maps highlighting the optimum regions for generating a single
intense attosecond pulse and coherent XUV radiation are presented. Moreover, a robust
plasma gating is developed to generate a super-intense phase-stabilized single attosecond
pulse. The hole-boring effect limits the most efficient high-frequency emission in one
laser cycle making it possible to isolate a single attosecond pulse. The generated pulse is
characterized by a stabilized spectral phase ψ(ω) ≈± π/2 and an ultra-broad exponential
spectrum up to keV region bounded by ROM scaling and CSE scaling. The unprecedented
intensity highlights the potential of the isolated attosecond pulse for performing
attosecond-pump attosecond-probe experiments.
