Highly coherent and stable pulses from the FERMI seeded free-electron laser in the extreme ultraviolet

• DOI: 10.1038/nphoton.2012.233
• Publication Date: 2012-09-21T10:11:51Z
• Authors: E. Allaria; R. Appio; L. Badano; W.A. Barletta; S. Bassanese; S.G. Biedron; A. Borga; E. Busetto; D. Castronovo; P. Cinquegrana; S. Cleva; D. Cocco; M. Cornacchia; P. Craievich; I. Cudin; G. D'Auria; M. Dal Forno; M.B. Danailov; R. De Monte; G. De Ninno; P. Delgiusto; A. Demidovich; S. Di Mitri; B. Diviacco; A. Fabris; R. Fabris; W. Fawley; M. Ferianis; E. Ferrari; S. Ferry; L. Froehlich; P. Furlan; G. Gaio; F. Gelmetti; L. Giannessi; M. Giannini; R. Gobessi; R. Ivanov; E. Karantzoulis; M. Lonza; A. Lutman; B. Mahieu; M. Milloch; S.V. Milton; M. Musardo; I. Nikolov; S. Noe; F. Parmigiani; G. Penco; M. Petronio; L. Pivetta; M. Predonzani; F. Rossi; L. Rumiz; A. Salom; C. Scafuri; C. Serpico; P. Sigalotti; S. Spampinati; C. Spezzani; M. Svandrlik; C. Svetina; S. Tazzari; M. Trovo; R. Umer; A. Vascotto; M. Veronese; R. Visintini; M. Zaccaria; D. Zangrando; M. Zangrando
• Keywords: Extreme ultraviolet; Free electron model; Amplified spontaneous emission; Free-electron laser

Free-electron lasers (FELs) are promising devices for generating light with laser-like properties in the extreme ultraviolet and X-ray spectral regions. Recently, FELs based on the self-amplified spontaneous emission (SASE) mechanism have allowed major breakthroughs in diffraction and spectroscopy applications, despite the relatively large shot-to-shot intensity and photon-energy fluctuations and the limited longitudinal coherence inherent in the SASE mechanism. Here, we report results on the initial performance of the FERMI seeded FEL, based on the high-gain harmonic generation configuration, in which an external laser is used to initiate the emission process. Emission from the FERMI FEL-1 source occurs in the form of pulses carrying energy of several tens of microjoules per pulse and tunable throughout the 65 to 20 nm wavelength range, with unprecedented shot-to-shot wavelength stability, low-intensity fluctuations, close to transform-limited bandwidth, transverse and longitudinal coherence and full control of polarization.