Author: De Ninno, G.
Paper Title Page
MOP073
 Chirped Pulse Amplification in a Seeded Free-electron Laser: Design of a Test Experiment at FERMI  
 
  • G. De Ninno, E. Allaria, I. Cudin, M.B. Danailov, A.A. Demidovich, S. Di Mitri, E. Ferrari, D. Gauthier, L. Giannessi, N. Mahne, G. Penco, L. Raimondi, P. Rebernik Ribič, C. Spezzani, L. Sturari, C. Svetina, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • H. Dacasa, B. Mahieu, P. Zeitoun
    LOA, Palaiseau, France
  • M. Fajardo
    IPFN, Lisbon, Portugal
  • E. Ferrari
    Università degli Studi di Trieste, Trieste, Italy
  • F. Frassetto, L. P. Poletto
    LUXOR, Padova, Italy
  • D. Gauthier
    University of Nova Gorica, Nova Gorica, Slovenia
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  
  In solid-state lasers, frequency chirping is employed to stretch a short pulse prior to amplification, mitigating the problems related to high power in the active medium. After amplification, the chirp is compensated in order to recover short pulse duration and, hence, high peak power. Chirped pulse amplification (CPA) in seeded FEL’s relies on a similar principle: the seed pulse is stretched in time before interacting with the electron beam. This permits one to create bunching on a larger number of electrons, and to (approximately) linearly increase the output energy of the generated FEL pulse. In ideal conditions, the chirp carried by the phase of the seed pulse is transmitted to the output phase of the FEL pulse. Chirp compensation after the last undulator allows production of a short (ideally Fourier-transformed) pulse and, therefore, a larger peak power with respect to what obtained, for the same conditions, in standard (i.e., no-chirp-on-the-seed) operation mode. In this paper, we present the preparatory studies (i.e., numerical simulations and compressor design), which have been carried out at FERMI, in view of performing the first test experiment of CPA on a seeded FEL.  
 
TUB02 Generation of Intense XVUV Pulses with an Optical Klystron Enhanced Self- amplified Spontaneous Emission Free Electron Laser 332
 
  • G. Penco, E. Allaria, G. De Ninno, E. Ferrari, L. Giannessi
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • G. De Ninno
    University of Nova Gorica, Nova Gorica, Slovenia
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  
  Fermi is a seeded FEL operating in high gain harmonic generation mode. The FEL layout is constituted by a modulator and six radiators separated by a dispersive section. The modulator and the radiators can be tuned to the same resonant frequency to set up an asymmetric optical klystron configuration where self amplified spontaneous emission can be generated and studied. This paper presents the experiment consisting in the analysis of the enhancement of the self-amplified spontaneous emission (SASE) radiation by the dispersion in the optical klystron. The FEL pulses produced with the optical klystron configuration are several order of magnitude more intense than in pure SASE mode with the dispersion set to zero, The experimental observations are in good agreement with simulation results and theoretical expectations. A comparison with the typical high-gain harmonic generation seeded Fel operation is also provided.  
slides icon Slides TUB02 [12.835 MB]  
 
TUP085 FERMI Status Report 564
 
  • M. Svandrlik, E. Allaria, F. Bencivenga, C. Callegari, F. Capotondi, D. Castronovo, P. Cinquegrana, M. Coreno, R. Cucini, I. Cudin, G. D'Auria, M.B. Danailov, R. De Monte, G. De Ninno, P. Delgiusto, A.A. Demidovich, S. Di Mitri, B. Diviacco, A. Fabris, R. Fabris, W.M. Fawley, M. Ferianis, E. Ferrari, P. Finetti, L. Fröhlich, P. Furlan Radivo, G. Gaio, D. Gauthier, F. Gelmetti, L. Giannessi, M. Kiskinova, S. Krecic, M. Lonza, N. Mahne, C. Masciovecchio, M. Milloch, F. Parmigiani, G. Penco, L. Pivetta, O. Plekan, M. Predonzani, E. Principi, L. Raimondi, P. Rebernik Ribič, F. Rossi, L. Rumiz, C. Scafuri, C. Serpico, P. Sigalotti, C. Spezzani, C. Svetina, M. Trovò, A. Vascotto, M. Veronese, R. Visintini, D. Zangrando, M. Zangrando
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  
  FERMI, the seeded FEL located at the Elettra laboratory in Trieste, Italy, is now in regular operation for users with its first FEL line, FEL-1, which covers the wavelength range between 100 and 20 nm. We will give an overview of the typical operating modes of the facility for users and we will report on the status of beamlines and experimental stations. Three beamlines are now opened for users, three more are in construction. Meanwhile, the second FEL line of FERMI, FEL-2, a HGHG double stage cascade covering the wavelength range 20 to 4 nm is still under commissioning; we will report on the latest results in particular at the shortest wavelength, 4 nm in the fundamental.  
 
TUC03 Generation of Optical Orbital Angular Momentum Using a Seeded Free Electron Laser 609
 
  • P. Rebernik Ribič, G. De Ninno, D. Gauthier
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  
  Funding: The research was in part funded by the TALENTS UP Programme (7th R&D Framework Programme, Specific Programme: PEOPLE - Marie Curie Actions - COFUND).
We propose an effective scheme for the generation of intense extreme-ultraviolet light beams carrying orbital angular momentum (OAM). The light is produced by a high-gain harmonic-generation free-electron laser (HGHG FEL), seeded using a laser pulse with a transverse staircase-like phase pattern. The transverse phase modulation in the seed laser is obtained by putting a phase-mask in front of the focusing lens, before the modulator. The staircase-like phase pattern is effectively transferred onto the electron beam in the modulator and the microbunching structure is preserved after frequency up-conversion in the radiator. During light amplification in the radiator, diffraction and mode selection drive the radiation profile towards a dominant OAM mode at saturation. With a seed laser at 260 nm, gigawatt power levels are obtained at wavelengths approaching those of soft x-rays. Compared to other proposed schemes to generate OAM with FELs, our approach is robust, easier to implement, and can be integrated into already existing FEL facilities without extensive modifications of the machine layout. 		 
 
THA02 Experimental Characterization of FEL Polarization Control with Cross Polarized Undulators 644
 
  • E. Ferrari, E. Allaria, G. De Ninno, B. Diviacco, D. Gauthier, L. Giannessi, G. Penco, C. Spezzani
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • J. Buck, M. Ilchen
    XFEL. EU, Hamburg, Germany
  • G. De Ninno, D. Gauthier
    University of Nova Gorica, Nova Gorica, Slovenia
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • Z. Huang, A.A. Lutman
    SLAC, Menlo Park, California, USA
  • G. Lambert, B. Mahieu
    LOA, Palaiseau, France
  • J. Viefhaus
    DESY, Hamburg, Germany
  
  Polarization control of the coherent radiation is becoming an important feature of recent and future short wavelength free electron laser facilities. While polarization tuning can be achieved taking advantage of specially designed undulators, a scheme based on two consecutive undulators emitting orthogonally polarized fields has also been proposed. Developed initially in synchrotron radiation sources, crossed polarized undulator schemes could benefit from the coherent emission that characterize FELs. In this work we report the first detailed experimental characterization of the polarization properties of an FEL operated with crossed polarized undulators in the Soft-X-Rays. Aspects concerning the average degree of polarization and the shot to shot stability are investigated together with a comparison of the performance of various schemes to control and switch the polarization  
slides icon Slides THA02 [5.383 MB]  
 
FRA02 Wave-Mixing Experiments with Multi-colour Seeded FEL Pulses 985
 
  • F. Bencivenga, A. Battistoni, F. Capotondi, R. Cucini, M.B. Danailov, G. De Ninno, M. Kiskinova, C. Masciovecchio
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  
  The extension of wave-mixing experiments in the extreme ultraviolet (EUV) and x-ray spectral range represents one of the major breakthroughs for ultrafast x-ray science. Essential prerequisites to develop such kind of non-linear coherent methods are the strength of the input fields, comparable with the atomic field one, as well as the high temporal coherence and stability of the photon source(s). These characteristics are easily achievable by optical lasers. Seeded free-electron-lasers (FELs) are similar in many respects to conventional lasers, hence calling for the development of wave-mixing methods. At the FERMI seeded FEL facility this ambitious task is tackled by the TIMER project, which includes the realization of a dedicated experimental end-station. The wave-mixing approach will be initially used to study collective atomic dynamics in disordered systems and nanostructures, through transient grating (TG) experiments. However, the wavelength and polarization tunability of FERMI, as well as the possibility to radiate multi-colour seeded FEL pulses, would allow to expand the range of possible scientific applications.  
slides icon Slides FRA02 [7.731 MB]  
 
TUB02 Generation of Intense XVUV Pulses with an Optical Klystron Enhanced Self- amplified Spontaneous Emission Free Electron Laser 332
 
  • G. Penco, E. Allaria, G. De Ninno, E. Ferrari, L. Giannessi
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • G. De Ninno
    University of Nova Gorica, Nova Gorica, Slovenia
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  
  Fermi is a seeded FEL operating in high gain harmonic generation mode. The FEL layout is constituted by a modulator and six radiators separated by a dispersive section. The modulator and the radiators can be tuned to the same resonant frequency to set up an asymmetric optical klystron configuration where self amplified spontaneous emission can be generated and studied. This paper presents the experiment consisting in the analysis of the enhancement of the self-amplified spontaneous emission (SASE) radiation by the dispersion in the optical klystron. The FEL pulses produced with the optical klystron configuration are several order of magnitude more intense than in pure SASE mode with the dispersion set to zero, The experimental observations are in good agreement with simulation results and theoretical expectations. A comparison with the typical high-gain harmonic generation seeded Fel operation is also provided.  
slides icon Slides TUB02 [12.835 MB]  
 
THA02 Experimental Characterization of FEL Polarization Control with Cross Polarized Undulators 644
 
  • E. Ferrari, E. Allaria, G. De Ninno, B. Diviacco, D. Gauthier, L. Giannessi, G. Penco, C. Spezzani
    Elettra-Sincrotrone Trieste S.C.p.A., Basovizza, Italy
  • J. Buck, M. Ilchen
    XFEL. EU, Hamburg, Germany
  • G. De Ninno, D. Gauthier
    University of Nova Gorica, Nova Gorica, Slovenia
  • L. Giannessi
    ENEA C.R. Frascati, Frascati (Roma), Italy
  • Z. Huang, A.A. Lutman
    SLAC, Menlo Park, California, USA
  • G. Lambert, B. Mahieu
    LOA, Palaiseau, France
  • J. Viefhaus
    DESY, Hamburg, Germany
  
  Polarization control of the coherent radiation is becoming an important feature of recent and future short wavelength free electron laser facilities. While polarization tuning can be achieved taking advantage of specially designed undulators, a scheme based on two consecutive undulators emitting orthogonally polarized fields has also been proposed. Developed initially in synchrotron radiation sources, crossed polarized undulator schemes could benefit from the coherent emission that characterize FELs. In this work we report the first detailed experimental characterization of the polarization properties of an FEL operated with crossed polarized undulators in the Soft-X-Rays. Aspects concerning the average degree of polarization and the shot to shot stability are investigated together with a comparison of the performance of various schemes to control and switch the polarization  
slides icon Slides THA02 [5.383 MB]