High-order sideband generation (HSG), as an analogue of the interband processes in high-harmonic (HHG) solids, is a nonperturbative nonlinear optical phenomenon semiconductors that are simultaneously driven by relatively weak near-infrared (NIR) laser and sufficiently strong terahertz (THz) field. We derive explicit formula for polarization vectors prototypical two-band model based on saddle-po...

High harmonic generation (HHG) in solid and gaseous targets has been proven to be a powerful avenue for the of attosecond pulses, whereas influence electron-phonon scattering on HHG is critical outstanding problem. Here we first introduce temperature dependent lattice vibration model by characterizing spacing fluctuation. Our results reveal that (i) structural disorder induced does not lead eve...

We report on the development of a high-order harmonic generation (HHG)-based ultrafast high-repetition-rate (250 kHz) monochromatic extreme ultraviolet (21.6 eV) source with polarization tunability, specifically designed for multi-modal dichroism in time- and angle-resolved photoemission spectroscopy. Driving HHG using an annular beam allows us to spatially separate high-power 515 nm driving la...

High-order harmonic generation (HHG) is a fundamental process which can be simplified as the production of high energetic photons from material subjected to strong driving laser field. This highly nonlinear optical contains rich information concerning electron structure and dynamics matter, for instance, gases, solids liquids. Moreover, HHG has recently attracted attention both attosecond scien...

Using the Hubbard model we study how process of high-order harmonic generation (HHG) is modified by beyond mean-field electron-electron correlation for both finite and bulk systems. A finite-size enhancement HHG signal found attributed to electrons backscattering off lattice edges. Additionally, with increasing strength an high-frequency regime spectrum found. This on-site Coulomb repulsion bet...

We study the higher-harmonic generation (HHG) using elliptically polarized two-color driving fields. The HHG via bi-chromatic counter-rotating laser fields is a promising source of circularly ultrashort XUV radiation at attosecond time scale. ellipticity or polarization pulses can be tweaked by modifying emitted harmonics' ellipticity, which controlled varying driver propose simple setup to con...

We address technical impediments to the generation of high-photon flux XUV frequency combs through cavity-enhanced high harmonic generation. These difficulties arise from mirror damage, cavity nonlinearity, the intracavity plasma generated during the HHG process, and imperfect phase-matching. By eliminating or minimizing each of these effects we have developed a system capable of generating > 2...

The production of extreme ultraviolet (XUV) radiation via nanoplasmonic field-enhanced high-harmonic generation (HHG) in gold nanostructures at MHz repetition rates is investigated theoretically in this paper. Analytical and numerical calculations are employed and compared in order to determine the plasmonic fields in gold ellipsoidal nanoparticles. The comparison indicates that numerical calcu...

A bright high harmonic source is presented delivering up to 10 photons per second around a central photon energy of 120 eV. Fully phase matched harmonics are generated in an elongated capillary reaching a cut-off energy of 160 eV. The high HHG photon fluence opens new perspectives towards seeding free electron lasers at shorter wavelengths than the state of the art. Characterization of the phas...

High harmonic generation (HHG) is a versatile technique for probing ultrafast electron dynamics. While HHG sensitive to the electronic properties of target, also depends on waveform laser pulse. As well known, (peak) positions, $\omega$, in high-harmonic spectrum can shift when carrier envelope phase (CEP), $\varphi$ varied. We derive formulae describing corresponding parametric dependencies CE...