Related papers: Enhancing keV high harmonic signals generated by l…
High harmonic generation traditionally combines ~100 near-infrared laser photons, to generate bright, phase matched, extreme ultraviolet beams when the emission from many atoms adds constructively. Here we show that by guiding a…
High-harmonic generation (HHG) normally requires a careful adjustment of the driving laser intensity (typically $10^{14} - 10^{15}$ W/cm$^2$) and gas medium parameters to enable good phase matching conditions. In contrast with conventional…
It is shown that under optimal conditions, the generation of the 3rd, 5th, 7th, and 9th harmonics of the short-wave, ultraviolet or vacuum ultraviolet, laser field by helium atoms is mainly due to transitions between bound states, and the…
High-order harmonic generation from atomic systems is considered in the crossed fields of a relativistically strong infrared laser and a weak attosecond-pulse train of soft x-rays. Due to one-photon ionization by the x-ray pulse, the…
Plasma high harmonics generation from an extremely intense short-pulse laser is explored by including the effects of ion motion, electron-ion collisions and radiation reaction force in the plasma dynamics. The laser radiation pressure…
High-harmonic generation in two-colour ($\omega-2\omega$) counter-rotating circularly polarised laser fields opens the path to generate isolated attosecond pulses and attosecond pulse trains with controlled ellipticity. The generated…
Using a high-frequency field superposed to a linearly polarized bichromatic laser field composed by a wave with frequency $\omega $ and a wave with frequency $2\omega $, we show it is possible to enhance the intensity of a group of high…
The below-threshold harmonic generation in the multiphoton ionization regime for a helium atom driven by the elliptically polarized laser field is studied numerically within the framework of two-dimensional (2D) and three-dimensional (3D)…
High-order harmonic generation (HHG) with relativistically strong laser pulses is considered employing electron ionization-recollisions from multiply charged ions in counterpropagating, linearly polarized attosecond pulse trains. The…
We consider harmonics generation and wave-mixing by two-color multi photon resonant excitation of three-level atoms/molecules in strong laser fields. The coherent part of the spectra corresponding to multicolor harmonics generation is…
The laser interaction with an electron-positron-ion mixed plasma is studied, from the perspective of the associated high-order harmonic generation. For an idealized mixed plasma which is assumed with a sharp plasma-vacuum interface and…
We show how bright, fully coherent, hard x-ray beams can be generated through nonlinear upconversion of femtosecond laser light. By using longer-wavelength mid-infrared driving lasers of moderate peak intensity, full phase matching of the…
A way to considerably enhance terahertz radiation, emitted in the interaction of intense mid-infrared laser pulses with atomic gases, in both the total energy and the electric-field amplitude is suggested. The scheme is based on the…
The interaction of relativistically strong tailored laser pulses with an atomic system is considered. Due to a special tailoring of the laser pulse, the suppression of the relativistic drift of the ionized electron and a dramatic…
We theoretically study high-order harmonic generation (HHG) from solid-phase systems in spatially inhomogeneous strong laser fields originated by resonant plasmons within a metallic nanostructure. The intensity of the second plateau in HHG…
We investigate the effect of dynamic electron correlation on high-harmonic generation in helium atoms using intense visible light (\lambda=390nm). Two complementary approaches are used which account for correlation in an approximate manner:…
Harmonic lasing of low-gain free electron laser oscillators has been experimentally demonstrated in the terahertz and infrared regions. Recently, the low-gain oscillator has been reconsidered as a promising candidate for hard x-ray free…
High-harmonic generation is one of the most extreme nonlinear-optical processes observed to date. By focusing an intense laser pulse into a gas, the light-atom interaction that occurs during the process of ionising the atoms results in the…
We generate high-order harmonics at high pulse repetition rates using a turnkey laser. High-order harmonics at 400 kHz are observed when argon is used as target gas. In neon we achieve generation of photons with energies exceeding 90 eV…
The generation of harmonics by atoms or ions in a two-color, coplanar field configuration with commensurate frequencies is investigated through both, an analytical calculation based on the Lewenstein model and the numerical ab initio…