Characterization of the high harmonics source for the VUV ellipsometer at ELI Beamlines

Abstract

In this paper, the authors present the characterization experiments of a 20 fs vacuum ultraviolet beam from a high harmonic generation source. The beam hits a silicon sample and passes a triple reflection gold polarizer located inside an ultrahigh vacuum chamber. The polarizer's Malus curve was obtained; the total acquisition time for each point of the curve was 30 s. This aims to be the first vacuum ultraviolet time-resolved user station dedicated to ellipsometry. The high harmonic beam is generated by a 12 mJ, 1 kHz, 20 fs, in-house-developed laser and detected by a back-illuminated charge-coupled device.

First experiments with a water-jet plasma X-ray source driven by the novel high-power–high-repetition rate L1 Allegra laser at ELI Beamlines

“…The L1 Allegra laser is sent from the L1 hall, located above E1, and can be directed to one of two types of secondary sources -an HHG source for XUV radiation (Hort et al, 2019(Hort et al, , 2020 or plasma X-ray sources (Nejdl et al, 2019). The HHG source serves two stations for XUV science: 'MAC' for atomic, molecular and optical science and coherent diffractive imaging (Klimesova ´et al, 2021), and 'ELIps' for XUV materials science applications (Espinoza et al, 2020). Complementary methods for ultrafast optical spectroscopy are also available (using support lasers): transient optical absorption (Naumova et al, 2018), stimulated Raman scattering (Andrikopoulos et al, 2020), time-resolved spectroscopic ellipsometry (Richter et al, 2021) and IR (1D and 2D) spectroscopy.…”

Update on laser-driven X-ray sources at ELI Beamlines

“…Laser focusing with f-numbers 80, 200, and 500 is currently utilized enabling efficient generation in various noble gases with both kHz laser drivers. The XUV beam is directed into two end-stations: a station dedicated to atomic molecular and optical sciences and coherent diffraction imaging [6] and a magneto-optical VUV ellipsometry station [7] dedicated to material science and surface science. Since the beamline commissioning various parts of it have been upgraded with respect to the original design to increase the photon number and improve the versatility and robustness of the source as well as to improve the characterization of the XUV beam [8].…”

Nanowire Grid Reflecting Polarizers for Ultraviolet Applications

“…An example of a configuration based on a gold triple-reflection was reported in [31], which can achieve a polarization between 90% and 96% at the energy range from 2 eV to 40 eV. In addition, a triple-reflected gold polarizer for testing VUV ELIps capabilities in the VUV spectral region from 30 eV to 45 eV has been developed [32]. Nevertheless, compact reflective polarizers which can achieve extremely high polarization in the spectral energy below 10 eV are still difficult to realize.…”