Final Activity Report Summary - ATTOTECH (Attosecond Technology) The aim of the project was to achieve significant progress on the control and the versatility of attosecond pulse sources. On the one hand, it was expected to generate tuneable attosecond pulses, energy and duration wise, on the other hand to get additional control on the structure of trains of attosecond pulses. Towards the first goal, we envisioned using broadband XUV multilayer mirrors. We made some significant improvements on the attosecond source in Lund to reach higher central frequency pulses, up to 70eV. This gave us the tools to better characterize the group delay dispersion of some XUV multilayer mirrors manufactured in Institut d'Optique in Orsay. The energy range of the data collected increased compared to the previous campaign. Besides a source of tuneable broadband attosecond pulses was developed and characterised. It delivers trains of pulses as short as 130 as, as a mean value, which constitutes the shortest train type source of attosecond pulse reported to our knowledge. In addition, this led to the creation of a spinoff company, Attotech HB which commercialises a kHz pulse valve. The first customers mainly come from the attosecond community. But some customers use these valves for molecular alignment as well, and contacts are taken with some other research fields. This confirms the broad interest in the technological developments carried out to achieve this task. The second point was to tailor the train of attosecond pulses itself, ie, find ways to control on demand the number and spacing of the pulses going from a train down to a single pulse. In collaboration with ETH in Zurich, an experimental setup combining a post compression stage in a filament and a two-colours scheme for the generation of high harmonics has been set on a kHz, carrier envelope phase stabilised laser system. Preliminary experimental results not fully analysed yet seem to show the potential of this technique to achieve the goal.
