We present the design, the optimization and the realization of multilayer mirrors for the transport and the compression of
attosecond pulses generated by high harmonics emission from 35 eV to 55 eV. At wavelength characterizations have
been performed on an attosecond source. We explore also the phase determination of the complex reflectivity from
photon-electron emission measurement on synchrotron beamline.
This communication describes the research work plan that is under implementation at the SPARC FEL facility in the
framework of the DS4 EUROFEL programme. The main goal of the collaboration is to study and test the amplification
and the FEL harmonic generation process of an input seed signal obtained as higher order harmonics generated both in
crystals (400 nm and 266 nm) and in gases (266 nm, 160 nm, 114 nm). The SPARC FEL can be con-figured to test
several cascaded FEL layouts that will be briefly analysed.