Kilohertz extreme-ultraviolet light source based on femtosecond high-order harmonic generation from noble gases

Abstract

International audienceA compact, versatile table-top kilohertz source of coherent extreme-ultraviolet (XUV) radiation in the wavelength region 18–100 nm, based on high-order harmonic generation from noble gases induced by a 40-femtosecond Ti:sapphire laser system, is presented. The XUV beamline delivers at its output 10^8 photons/s at a wavelength of 23 nm. The monochromatized XUV radiation is directly focused onto a 10^-2-mm^2 spot by a toroidal grating, allowing one to reach intensities higher than 10^6 W/cm^2. Optimization results are presented for a new XUV-generating geometry, utilizing a ‘semi-infinite' quasi-static gas cell and strong focusing. In those conditions, we observe an anomalous inversion between the cutoffs of argon and krypton, with the krypton spectrum extending to much higher orders than expected in an adiabatic limit

High-order-harmonic generation from dense water microdroplets

“…Most of the phase-matching studies have been performed on gaseous, atomic targets. Therein, mainly three different geometries have been applied: the gas jet [34], the finite gas cell [35,37], and the semi-infinite gas cell [36]. In contrast to the gaseous state, HHG from a liquid target is rather unexplored.…”

“…de Experimentally, HHG has been performed using atoms [1] and molecules [28] as a target in several thermodynamical states, such as gaseous, liquid, or solid state [1,22,23,[29][30][31][32][33]. Moreover, different geometries with impact on the phasematching conditions have been used for HHG [22,23,[34][35][36]. Most of the phase-matching studies have been performed on gaseous, atomic targets.…”

Isolated 170 as Pulse Generation in the XUV

“…In case that the HHG process is driven by multi-cycle laser pulses, the electrons encounter the parent ion every half-cycle of the electric field which results in a series of XUV emissions that manifest themselves in the spectral domain as high harmonics [6][7][8]. In contrast, when few-cycle laser pulses are employed, the energy of the emitted light wave packet from consecutive recombination events close to the peak of the pulse, can vary substantially from the maximum emitted energy.…”

XUV Transient Absorption Spectroscopy: Probing Laser-Perturbed Dipole Polarization in Single Atom, Macroscopic, and Molecular Regimes

“…Figure 2a,b shows two types of geometry that we used to produce XUV attosecond pulse trains (APTs) by the HHG process; namely, a gas cell [15,16] and a gas-filled capillary waveguide [17,18]. The geometry of the gas cell can be described as a semi-infinite gas cell (SIGC), where a thin aluminum plate can be used as a gas-vacuum barrier with a hole drilled in situ by NIR pulses.…”