ATTOLAB SE10: a versatile and integrated beamline for attosecond physics on gases and surfaces
Résumé
In recent years, increased reliability and stability of ultrafast energetic lasers based on Ti:Sapphire technology has raised the interest of a broad community of users appealed by ultrashort Extreme Ultra Violet (XUV) sources. In particular, focusing these lasers on gas targets, the process of High order Harmonic Generation (HHG) supplies an XUV spectrum that shows unique specificities as for its high degree of coherence, its low duration, which lies in the attosecond to femtosecond range, and its excellent synchronization to a Visible-IR laser that may be used for pump-probe experiments. Starting from a λ = 800 nm wavelength, typical HHG spectra lie in the 10 eV-120 eV range, which can address a large variety of applications from solid state physics (e.g. spin dynamics, dynamics of the so-called Dirac fermions in topological insulators, multi-ferroic materials, e.g., oxides) and gas phase chemical physics (e.g. time-resolved photoionization in the core- and valence shell of atoms/molecules, highly non-linear harmonic spectroscopy...).
Based on this scientific landscape, we designed an ultrafast XUV facility which offers free- ports to users from solid state and chemical physics backgrounds. The laser system is a Ti:Sapphire system which delivers 23 fs CEP stabilized pulses of 2 mJ at a 10 kHz repetition rate. The beam is focused in a continuous gas jet to produce HHG spectra. A first XUV beamline, currently under commissioning, has been designed by consensus among potential users and coupled to this HHG source. It finally offers three kinds of XUV light beams that can be commuted within 15 min without changing any other experimental parameter: a very broadband, broadband, and narrowband operating points. The spectral bands extend over the full 10-100 eV range, with respectively 20 eV, 1 to 5 eV and 100 meV FWHM, corresponding to pulse durations in the 100 as, 1 fs and 10 fs ranges. All are synchronized, down to attosecond precision with laser pump beams. Extreme care has been taken to provide a very stable and reproducible beamline which meets the needs of the scientific community. In this communication, the performance and technological choices for this beamline will be presented.