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Temporal and Spatial pulse shaping at CEA SACLAY

Temporal and Spatial pulse shaping at CEA SACLAY. D.Garzella, O.Gobert, S. Grabielle, J-F. Hergott, Ph. Hollander , D. Jourdain, F. Lepetit, M. Perdrix, O.Tcherbakoff CEA/DSM/DRECAM/SPAM T.Oksenhendler FASTLITE.

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Temporal and Spatial pulse shaping at CEA SACLAY

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  1. Temporal and Spatial pulse shaping at CEA SACLAY D.Garzella, O.Gobert, S. Grabielle, J-F. Hergott, Ph. Hollander, D. Jourdain, F. Lepetit, M. Perdrix, O.Tcherbakoff CEA/DSM/DRECAM/SPAM T.Oksenhendler FASTLITE This work has been partially supported by the EU commission in the Sixth Framework Program Contract n° 011935 EUROFEL

  2. Overview • Motivations • Saclay Laser Interaction Center • EUROFEL and ARC en CIEL • Photoinjector Studies • fs Longitudinal Pulse Shaping • Goal • Phase/Amplitude Modulation • IR shaping and THG • THG and UV Shaping • Spatial Pulse Shaping • Goal • UV Beam Shaper • Conclusions and Further Studies

  3. SPAM Atoms, Photons and Molecules Laboratory Matter under extremes conditions Laboratoire Francis Perrin Femtosecond Laser Servers • Applications of Plasmas • High Energy Density Matter • Attophysics • High Intensity Physics • Dynamics of Chemical Reactivity • Excited Biomolecules • Nanometrics Buildings • Theoretical Chemistry Technical Support (Mechanics, Vacuum, CAD) Laser Sources Teams Saclay Laser Interaction Center

  4. for scientists CEA, France, Europe 60%, 20%, 20% Open Sources More than 90% Reliability SLIC 10 years experience - 4 servers – 10 beamlines Luca : tunability from 10 to 800 nm (HHG, ) SOFOCKLE, PLFA : High Repetition Rate (KHz) UHI10 : High Power 10 TW ( ) NOPA Complementarity 100 TW in 2008

  5. JADE Compressor JADE (Gain x10) JADE (527 nm, 20 W) 4.7W JADE Ti:Sa 30 fs USERS JADE Multipass Amplifier 15 fs, 70 nm Regenerative Amplifier (Gain x105) Master Oscillator 2W POCKELS 6W dazzler l/2 POCKELS ph2 VERDI (532 nm, 4 W) 9W Ti Sa POCKELS 660mW ph1 TiSa POCKELS Preamplifier (Gain x3) Stretcher PLFA (Tunable Femtosecond Laser Platform) 1 KHz, 20 mJ, 30 fs pulses

  6. , towards the Technical Design Report • To initiate the overview for ARC EN CIEL EUROFEL/ARC en CIEL • CEA/SPAM is involved in 3 WG in the 2005-2007 EUROFEL program • Photoinjectors • Synchronization • Seeding and Harmonic Generation

  7. PhotoInjectors related Studies • R&D program on ultrashort laser pulses for Accelerator Physics community • 3 high Power Laser Facilities (SLIC) • Temporal and Spectral Diagnostics • Broadband Secondary Emission sources (OPAs, HHG in gases) • Aiming at creating an Injector Test Stand • Lasers • Photocathodes • Guns ?

  8. Motivations • Saclay Laser Interaction Center • EUROFEL and ARC en CIEL • Photoinjector Studies • fs Longitudinal Pulse Shaping • Goal • Phase/Amplitude Modulation • IR shaping and THG • THG and UV Shaping • Spatial Pulse Shaping • Goal • UV Beam Shaper • Conclusions and Further Studies

  9. 1 nC Charge Requirements For a UV laser pulse (l=266 nm) Goal • Obtention of a • supergaussian-like • temporal pulse. FWHM ~ 5- 20 ps, Rise time < 1 ps Fall time < 1 ps Ripples < +/- 10% max (critical periodicity, instabilities?) Lambda ~ 266 nm Energy/pulse up to 1mJ Energy fluctuations ? 50 nJ -1 mJ Cs2Te Cathodes (ARC EN CIEL, Flash, FZD) 0.5 % - 10 % 50-500 mJ 10-5-10-4 Metallic (e.g. copper) NC cathodes (SPARC, Fermi) 100 mJ 5 x 10-5 SC All Niobium cathodes (BNL) Temporal Structure NC RF gun (SPARC, Fermi) Single Pulse, 10-50 Hz 1-9 MHz pulse trains, 1-800 ms, 1-10 Hz NC RF gun (FLASH, XFEL) NC RF gun and DC/RF SC gun (ARC EN CIEL, FZD, Pekin Univ.) CW Single Pulse, 1-10 KHz

  10. Required Pulse Shapes • Super Gaussian Pulses (« beer cans », « pancakes » ?) • Ellipsoidal Pulses • Quadratic Ramp (see M. Trovo’ et al. , FEL 2006)

  11. Amplitude and Phase Modulation : the Dazzler Polychromatic acoustic pulse A matched to Polychromatic optical pulse E A( acoustic)  50% for 20fs  ~7ps <0.3nm @800nm Eout()=A(acoustic) Ein() Eout(t)=A(α t)  Ein(t) Ein Eout Amplitude and Phase Measurement • Define the temporal Target 2) Spectral Interferometry Spectrometer I.R. beam 800 nm, 50 fs FT Stretcher mainly j(2) IR Dazzler UV Up-converter IR beam 8OO nm, ~10 ps FT Shaped IR beam 800 nm, ~ 5 ps Shaped U.V. beam 266 nm

  12. Phase retrieving Spectral interferogram Fourier Transform-1 Time domain Time domain Filtering & Fourier Transform Spectral phase Spectral Amplitude &phase Combination Fourier Transform-1 Temporal intensity

  13. Generating square time shapes : adding phase shaping temporal phase >3ps, rise time<400fs Initial short pulse 50fs  Time *Bandwidth > 60 Fourier Transform (with phase) Bandwidth matching  Spectral Amplitude & Phase shaping

  14. Generating parabolic time shapes : adding phase shaping temporal phase Parabolic >3ps  Time *Bandwidth > 60 Initial short pulse 50fs Fourier Transform (with phase) Bandwidth matching  Spectral Amplitude & Phase shaping

  15. Numerical example : Amplitude Modulation and Quadratic/Complex Spectral Phase

  16. Experimental setup • One line of LUCA laser (2 TW system 1/3 CPA laser facility at Saclay Laser Interaction Center) : some µJ, 800 nm, FWHM ~20 nm, tp~ps • Spectral interferometry (Mach-Zenhder interferometer, Dazzler I.R. HR (0.3 nm resolution) in one arm, single shot acquisition…)

  17. Amplitude modulation Supergaussian Pulse GaussianSuperGaussian

  18. Phase modulation

  19. Spectrometer P P Dazzler Pockels Oscillator Dazzler IR WB resolution 0.6 nm Single-Shot Oscillator Pulse Shaping (I)

  20. Single-Shot Oscillator Pulse Shaping (II)

  21. Single-Shot Oscillator Pulse Shaping (III)

  22. Single –Shot result in the IR

  23. Direct UV Pulse Shaping Experimental set-up 266nm 800nm UV-Dazzler KDP 20Hz Ti:Sa Laser system 3ω Amplitude spectrometer Phase spectrometer Output

  24. UV-Dazzler KDP 266nm 20Hz Ti:Sa Laser system 3ω Amplitude measure spectrometer Phase measure spectrometer Experimental Results (I) Direct UV pulse shaping : UV-AOPDF KDP Experimental results Temporal intensity result

  25. UV-Dazzler KDP 266nm 20Hz Ti:Sa Laser system 3ω Amplitude measure spectrometer Phase measure spectrometer Experimental Results (II) Temporal intensity result

  26. Ellipsoidal pulse shaping • (very) preliminary work. • Amplitude (+phase) modulation at 266 nm • Amplitude (+phase) modulation at 800 nm+spatial shaping. • Cross-phase modulation to realize spatio-temporal shaping.

  27. Motivations • Saclay Laser Interaction Center • EUROFEL and ARC en CIEL • Photoinjector Studies • fs Longitudinal Pulse Shaping • Goal • Phase/Amplitude Modulation • IR shaping and THG • THG and UV Shaping • Spatial Pulse Shaping • Goal • UV Beam Shaper • Conclusions and Further Studies

  28. Isodensity Cylinder of Photoelectrons (« Beer Can ») Option 1 : Amplitude Modulation • Option 2 : Spatial phase & amplitude modulation • Large Depth of Field • Amplitude wavefront can be tilted, thus compensating ellipticity on the cathode • Photons time arrival ? • Modulate Wavefront pattern ? UV laser pulse t~10 ps Electron Bunch photocathode Pulse Shaper Hoffnagle/Jefferson (Opt. Eng. 42(11) 3090–3099 November 2003 Deformable Mirror

  29. Pulse Shaper Basics Spherical Plan Lens Spherical Plan Lens Define the Aspherical Elements

  30. Pulse Shaper : ZEMAX Ray Tracing (I) Aspherical Lens n°2 Aspherical Lens n°1 Stretching Factor : 0.1 on the vertical scale

  31. Pulse Shaper : ZEMAX Ray Tracing (II) Asphère n°1 Asphère n°2 Faisceau collimaté Distribution homogène des rayons

  32. Pulse Shaper : ZEMAX Ray Tracing (III)

  33. Pulse Shaper : ZEMAX Ray Tracing (IV) Input gaussian Spatial Distribution

  34. Beam Propagation (I)

  35. Beam Propagation (II) l=550 nm, Input waist w0=2.366 mm, Aperture= 4 mm

  36. Beam Propagation : Depth of Field (I) Z=0 Z = 30 cm Z = 50 cm Z = 1 m Z = 2 m Z = 9 m

  37. Beam Propagation : Depth of Field (II)

  38. Input Beam Wavefront Dependency

  39. Input Beam Size Dependency

  40. 3 w generator Gaussian UV Input pulse Generation Non perfect gaussian Beam: Amplitude and wavefront modulation Filtering Hole Collimated gaussian Beam 3 Lenses System (f,-f/4,f) • Requested Specifications : • Input Collimated Beam • Output Collimated Beam • Variable Magnification in [1/2,2] • Operating Wavelength : 266 nm

  41. Conclusion and Further Studies • IR and UV longitudinal pulse shaping • 3 ps square and parabolic pulses obtained • Ongoing experiments for amplified 1 mJ UV pulses • A « real » ellipsoidal pulse • UV Spatial Shaping • UV Beam Shaper Test is going just right now! • UV Deformable Mirror very soon ! • Combination of both • Complete Shaping

  42. Conclusion and Further Studies (II) • R&D on : • UV @266 nm and @200 nm high pulse energy sources • Multiparameters photoemission (energy, spatial amplitude and phase modulation, wavelength, angle-resolved) • High Repetition Rate Sources Thank You for your attention! TELL ME WHAT YOU WANT!!

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