Related papers: Ultrahigh harmonics from laser-assisted ion-atom c…
We predict high-order harmonics in which the polarization within the spectral bandwidth of each harmonic varies continuously and significantly. For example, the interaction of counter-rotating circularly-polarized bichromatic drivers having…
The harmonic emission from cluster nanoplasmas subject to short, intense infrared laser pulses is analyzed by means of particle-in-cell simulations. A pronounced resonant enhancement of the low-order harmonic yields is found when the Mie…
A detailed quantum-electrodynamic calculation of muon pair creation in laser-driven electron-positron collisions is presented. The colliding particles stem from a positronium atom exposed to a superintense laser wave of linear polarization,…
High-order harmonic generation via single-slit diffraction of relativistic laser pulses is investigated. Using fully kinetic 2D and 3D particle-in-cell simulations, we show that interesting optical phenomena emerge, including the generation…
We experimentally investigate the generation of above-threshold harmonics completely from argon atoms on an excited state using mid-infrared femtosecond laser pulses. The highly nonlinear dependences of the observed signal on the pulse…
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…
The dynamics of an electron bunch irradiated by two focused colliding super-intense laser pulses and the resulting gamma and electron-positron production are studied. Due to attractors of electron dynamics in a standing wave created by…
We present a theoretical model of high-harmonic generation from diatomic molecules. The theory includes effects of alignment as well as nuclear motion and is used to predict results for N$_2$, O$_2$, H$_2$ and D$_2$. The results show that…
We observe the generation of high harmonics in the plane perpendicular to the driving laser polarization and show that these are driven by the spin-orbit interaction. Using R-Matrix with time-dependence theory, we demonstrate that for…
When a high-power, femtosecond, circularly polarized (CP) laser pulse is incident on a micrometer-scale aperture in a solid foil target, it drives surface plasma oscillation, generating high-order harmonic vortices in the diffracted light.…
We use extreme-ultraviolet interferometry to measure the phase of high-order harmonic generation from transiently aligned CO2 molecules. We unambiguously observe a reversal in phase of the high order harmonic emission for higher harmonic…
When a high power laser beam irradiates a small aperture on a solid foil target, the strong laser field drives surface plasma oscillation at the periphery of this aperture, which acts as a "relativistic oscillating window". The diffracted…
We theoretically investigate photo-excitation of electron-hole pairs and high harmonic generation in the bulk of zinc oxide (ZnO) subjected to intense femto-second laser pulses with mid-infrared wavelength. The main microscopic mechanism of…
High-harmonic generation by a highly non-linear interaction of infrared laser fields with matter allows for the generation of attosecond pulses in the XUV spectral regime. This process, well established for atoms, has been recently extended…
Photoionization of atoms by high-order harmonics in the presence of a laser may lead to quantum interference from which information about the photoionization dynamics or the light fields can be extracted. Traditionally, this interference…
High harmonic generation due to the interaction of a short ultra relativistic laser pulse with overdense plasma is studied analytically and numerically. On the basis of the ultra relativistic similarity theory we show that the high harmonic…
High-harmonic generation by a laser-driven solid slab is simulated using time-dependent density functional theory. Multiple harmonic plateaus up to very high harmonic orders are observed already at surprisingly low field strengths. The full…
High-order harmonic generation in multiphoton ionization regime is studied theoretically to examine the resonant effects of the generating particle. We solve the time-dependent Schr\"odinger equation for In+ in the laser field by expanding…
Harmonic generation in the limit of ultra-steep density gradients is studied experimentally. Observations demonstrate that while the efficient generation of high order harmonics from relativistic surfaces requires steep plasma density…
Several correlation and interference effects in strong-field physics are investigated. We show that the interference of continuum wave packets can be the dominant mechanism of high-harmonic generation (HHG) in the over-the-barrier regime.…