Spatial and temporal metrology of intense attosecond pulses

Abstract: Attosecond pulses are short enough to capture the electronic dynamics in atoms and molecules. The work presented in this thesis deals with the generation and optimization of attosecond extreme-ultraviolet (XUV) pulses. The goal is to progress towards the realization of time-resolved nonlinear experiments at the intense XUV beamline of the Lund High-Power Laser Facility.The XUV flux was optimized using a loose focusing geometry. This led to a formalization of scaling laws for high-order harmonic generation (HHG) and more generally for nonlinear optics in gases, e.g., filamentation. A high intensity on target was achieved by focusing the high XUV flux using a pair of toroidal mirrors in a Wolter-like configuration.Spatial properties of the high-order harmonics were studied in details. Wavefront measurements of the harmonics were performed, both in the far field and after the refocusing optics, as well as spectrally resolved measurements. The origin of XUV aberrations is discussed, and the variation of the harmonic divergence depending on the generation position relative to the fundamental focus is studied.The intense XUV beamline and its first nonlinear experiments are presented. An interferometer to split-and-delay the beam was developed. Tests were performed, showing the capacity to provide attosecond resolution fortime-resolved experiments in the beamline.The high XUV intensity on target combined with the attosecond interferometer opens the door to perform XUV-pump XUV-probe experiments.