Roussel, EleonoreAllaria, EnricoCallegari, CarloCoreno, MarcelloCucini, RiccardoDi Mitri, SimoneDiviacco, BrunoFerrari, EugenioFinetti, PaolaGauthier, DavidPenco, GiuseppeRaimondi, LorenzoSvetina, CristianZangrando, MarcoBeckmann, AndreasGlaser, LeifHartmann, GregorScholz, FrankSeltmann, JoernShevchuk, IvanViefhaus, JensGiannessi, Luca2017-05-302017-05-302017-05-30201710.3390/photonics4020029https://infoscience.epfl.ch/handle/20.500.14299/137867WOS:000400154700010The control of polarization state in soft and hard X- ray light is of crucial interest to probe structural and symmetry properties of matter. Thanks to their Apple-II type undulators, the FERMI-Free Electron Lasers are able to provide elliptical, circular or linearly polarized light within the extreme ultraviolet and soft X- ray range. In this paper, we report the characterization of the polarization state of FERMI FEL-2 down to 5 nm. The results show a high degree of polarization of the FEL pulses, typically above 95%. The campaign of measurements was performed at the Low Density Matter beamline using an electron Time-Of-Flight based polarimeter.free-electron laserextreme ultravioletsoft X-raypolarization controltext::journal::journal article::research article