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We present two interferometry schemes in the extreme ultraviolet, based on either the wave-front division of a unique harmonic beam (1st scheme) or two spatially separated, phase-locked harmonic sources (2nd scheme). In the first scheme using a Fresnel bimirror interferometer, we measure the degree of spatial coherence of the 13 th harmonic generated in xenon, as a function of different parameters
Along with the review of the technological frame that will be available at the Extreme Light Infrastructure Attosecond Light Pulse Source (ELI-ALPS) we present considerations applicable to large-scale attosecond sources driven by high-power laser pulses.
Scaling attosecond sources to higher pulse energy and/or repetition rate can benefit many applications. We present a scaling framework for nonlinear light-matter interactions, applicable to attosecond pulse generation and other nonlinear phenomena as e.g. filamentation.
We investigate the influence of a Fano resonance on the delays for electron emission in two-photon, near-resonant ionization of argon. The delays were measured using an interferometric method that employed an attosecond pulse train.
A compact, high-repetition rate optical parametric chirped pulse amplifier system emitting CEP-stable, few-cycle pulses with 10 μJ of pulse energy is reported for the purpose of high-order harmonic generation. The system is seeded from a commercially available, CEP-stabilized Ti:sapphire oscillator, delivering an octave-spanning spectrum from 600-1200 nm. The oscillator output serves on the one ha
The recently demonstrated momentum shearing interferometry technique, aimed at recovering phase information about electronic wave packets (EWP) will be presented. Possibilities to improve this technique will be discussed.
Ultrashort light pulses, as short as 100 as, can be produced from high harmonic generation (HHG) in an atomic gas medium. This major achievement of the last 6 years in high field physics has now been demonstrated in different conditions of medium-field interaction [1].
We measured the frequency chirp rate of harmonics 13 to 23 in argon by cross-correlation with a short femtosecond probe pulse. We directly measured the negative chirp due to the atomic dipole phase and demonstrated that an additional chirp on the pump pulse was transferred to the qth harmonic as q times the fundamental chirp.
We present one-color (IR) and two-color (single attosecond XUV pulse + IR) experiments where the sub-cycle evolution of the electric field of light is used to control the dissociative ionization of hydrogen and deuterium molecules.
We modulate temporally the polarization of a ∼ 30 fs, 800 nm IR pulse and use it to generate high order harmonics. The harmonic emission can clearly be confined and the XUV pulse duration can be continuously tuned from - 5 - 7 fs to 50 fs.
We present experiments, supported by time-dependent Schrödinger simulations, on the dynamics of Helium bound states after an attosecond excitation in the presence of a strong infrared laser field.
The essence of ELI-ALPS, the laser driven secondary sources ranging from X-ray and X-UV to THz with duration as short as tens of attoseconds, are designed to be available for users from 2016.
We discuss the role of many-electron interactions in multiphoton multielectron ionization of heavy atoms and try to indicate the relative importance of collective effects and screening, relaxation and shakeup, and Fermi sea correlations. The purpose of the work is to look for approximations in which the photoemission processes have been renormalized in consistent ways with respect to the field and
We report the angular distributions of high-order harmonic radiation generated in neon and in argon using a 140 fs Cr:LisAF laser system. The profiles show an evolution from Gaussian to near flat-top. No substructure is observed except at the highest intensity in a completely ionized gas. The divergence of the harmonics is found to depend essentially on whether they belong to the plateau or to the
We study the role of propagation effects in high-order harmonic-generation experiments. The phase-matching integrals are calculated in the weak-field limit by taking into account the dispersion of the rare-gas medium at each harmonic frequency and the absorption of the harmonics. The refractive indices of the rare gases are deduced from a calculation of the dynamic polarizabilities within the fram
We present theoretical studies of high-order harmonic generation in a rare-gas medium. The experimental results obtained at Saclay with a 1064 nm Nd-YAG laser in the 1013 W cm-2 intensity range are summarized. The harmonic emission strengths first decrease rather steeply for the first orders, then form a long plateau up to the 21st harmonic in xenon, or up to the 33rd harmonic in argon, before dec
