Author: Fajardo, M.
Paper Title Page
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.  
The Creation of Large-Volume, Gradient-Free Warm Dense Matter with an X-Ray Free-Electron Laser  
  • A. Levy
    UPMC, Paris, France
  • P. Audebert, J. Fuchs, M. Gauthier
    LULI, Palaiseau, France
  • M. Cammarata, D.M. Fritz, H.J. Lee, R.W. Lee, H. Lemke, B. Nagler
    SLAC, Menlo Park, California, USA
  • O. Ciricosta, S.M. Vinko, J.S. Wark
    University of Oxford, Clarendon Laboratory, Oxford, United Kingdom
  • F. Deneuville, F. Dorchies, C. Fourment, O. Peyrusse
    CELIA, Talence, France
  • J. Dunn, A. Graf, J. Park, R. Shepherd, A. Steel
    LLNL, Livermore, California, USA
  • M. Fajardo
    IPFN, Lisbon, Portugal
  • J. Gaudin
    XFEL. EU, Hamburg, Germany
  • G. Williams
    IST, Lisboa, Portugal
  We report on an experiment performed using the hard x-ray beamline (X-ray Pump Probe-XPP) at the Stanford Linac Coherent Light Source (LCLS) free electron laser adapted to the study of high-pressure high-energy density states. This warm dense matter regime, which is barely described by present-day theoretical models, is poorly understood due to the difficulty of achieving these conditions in a manner that allows accurate diagnosis. The development of free electron lasers opens a unique opportunity to generate this regime in laboratory allowing one to efficiently and uniformly heat the matter up to 10 eV within less than 100 fs. In this context, we irradiated thin Ag foils with a 9 keV x-ray beam of 60 fs duration and an irradiance approaching 1016 W/cm2. The temporal evolution of the sample was monitored with two time-and-space resolved interferometry diagnostics measuring the phase of an optical laser beam reflected from the front and back of the sample. This measurement had provided crucial information on the heating uniformity and on the achievable temperature. These conclusions have been obtained by means of a precise modelling of this regime of interaction.  
slides icon Slides FRA03 [2.181 MB]