Related papers: Helicity reversion in high harmonic generation dri…
High-harmonic generation (HHG) involves the up-conversion of a high-intensity driving field into its harmonic orders. This process is intrinsically non-classical, requiring from quantum mechanics for a complete explanation as, under…
High harmonic generation (HHG) is a powerful probe of electron dynamics on attosecond to femtosecond timescales and has been successfully used to detect electronic and structural changes in solid-state quantum materials, including…
We compute the two-loop helicity amplitudes for the production of three photons at hadron colliders in QCD at leading-color. Using the two-loop numerical unitarity method coupled with analytic reconstruction techniques, we obtain the…
The first high harmonic spectrum, containing only the odd orders, was observed in experiments 30 years ago (1987). However, a spectrum containing pure even harmonics has never been observed. We investigate the generation of pure even…
We theoretically investigate correlated electron dynamics in high-harmonic generation (HHG), using all-electron \emph{ab initio} simulations for three-dimensional real alkali-metal atoms. The resulting harmonic spectra exhibit a plateau…
We present theoretical investigations of high-order harmonic generation (HHG) resulting from the interaction of noble gases with localized surface plasmons. These plasmonic fields are produced when a metal nanoparticle is subject to a…
In high harmonic generation (HHG), non-dipole effects become increasingly significant at long driving wavelengths, as the magnetic field leads to a lateral drift of the continuum electron, which disrupts the electron recollision and…
We show that the divergence of extreme ultraviolet pulses from high harmonic generation, which is directly linked to the shape and size of the refocused beam, can be controlled by the relative delay between the fundamental and its intense…
We generate high-order harmonics of a mid-infrared laser from a silicon single crystal and find their origin in the recollision of coherently accelerated electrons with their holes, analogously to the atomic and molecular case, and to ZnO…
We analyze the crystal orientation-dependent polarization state of extreme ultraviolet (XUV) high-order harmonics from bulk magnesium oxide crystals subjected to intense linearly polarized laser fields. We find that only along high-symmetry…
We study the influence of the polarization states of femtosecond two-color pulses ionizing gases on the emitted terahertz radiation. A local-current model and plane-wave evaluations justify the previously-reported impact on the THz energy…
Helicity amplitudes and differential cross section of high-energy $e^+e^-$ photoproduction accompanied by bremsstrahlung in the electric field of a heavy atom are derived. The results are exact in the nuclear charge number and obtained in…
The strong ellipticity dependence of high-harmonic generation in gases enables numerous experimental techniques that are nowadays routinely used, for instance, to create isolated attosecond pulses. Extending such techniques to high-harmonic…
We present a theoretical analysis of high-order harmonic generation from ion-atom collisions in the presence of linearly polarized intense laser pulses. Photons with frequencies significantly higher than in standard atomic high-harmonic…
Two different induced effects of a laser falling edge on high-order harmonic generation are resolved by solving numerically full-dimensional electronic time-dependent Schr\"{o}dinger equation beyond the Born-Oppenheimer approximation. The…
We present theoretical studies of high-order harmonic generation (HHG) produced by non-homogeneous fields as resulting from the illumination of plasmonic nanostructures with a short laser pulse. We show that both the inhomogeneity of the…
Nonlinear metasurfaces have become prominent tools for controlling and engineering light at the nanoscale. Usually, the polarization of the total generated third harmonic is studied. However, diffraction orders may present different…
High-order harmonic generation (HHG) is combined with resonant x-ray excitation of a core electron into the transient valence vacancy that is created in the course of the HHG process. To describe this setting, I develop a…
We study electron-positron pair production within two counter-propagating, circularly polarized electromagnetic fields through the Wigner formalism. We numerically generate high-resolution momentum maps to perform a detailed spectroscopic…
We investigated the high-order harmonic generation by interacting time-delayed, linearly polarized bi-chromatic laser pulses with the atomic target. The frequency ratio of secondary to primary fields ($\omega_2/\omega_1$), along with the…