HHG source developments

HHG source developments (High Harmonics Generation) for FEL seeding activities has shown great progress. A new HHG source based on the mix of two colors (fundamental laser wavelength and his second harmonic) with two linear and crossed polarizations was developed. Collaboration with Lomonossov Institute of Moscou successfully explain the main features of this new sources. The wavefront and the spatial profiles qualities were improved. The degree of polarization, the polarization axis, and the degree of ellipticity, were measured, in two different spectral ranges VUV (260 nm to 100 nm) with low harmonics orders, and in XUV (60 nm to 20 nm) with high order harmonics. The first range has been chosen to perform experiments in order to demonstrate the amplification of coherent light in a plasma-based free-electron lasers, with the collaboration of the synchrotron Soleil in France. The second one was dedicated to demagnetization studies of metallic layers, rare earth and transition metals, with a strong collaboration with Paris 6 university LCPMR laboratory. Pioneer work on demagnetization through different techniques such as magnetic diffusion and circular dichroism were achieved with recently the measurement of the time evolution of magnetization state in the sub 30 fs time scale using the Faraday effect. Furthermore, an XUV polarizer/analyzer system for XUV to measure the polarization properties of the FERMi at Elletra Free electron laser in Italy has been realized. Another variation of the system was used to measure the polarization properties of a plasma-based X-ray laser at 32 nm.