BNL/INFN/SLAC Dazzler Studies Proposed R&D at ANL and LLNL Summary

1. Injector Drive Laser R&DD. H. Dowell, SLACH. Loos, B. Sheehy, XJ. Wang, BNLL. Serafini ,C. Vicario, INFNLCLS Week, January 25-27, 2005 BNL/INFN/SLAC Dazzler Studies Proposed R&D at ANL and LLNL Summary

2. BNL/SLAC/INFN Laser Pulse Shaping

3. Dazzler - FastLite Inc. acousto-optic dispersive filter (P. Tournois et al.) TeO2 crystal acoustic wave (computer programmable) - spectral amplitude - temporal phase Dazzler in DUVFEL Drive Laser Courtesy of Yuzhen Shen, Carlo Vicario, B. Sheehy, XJ Wang

4. DUVFEL Drive Laser Layout with Dazzler Courtesy of B. Sheehy

5. Laser Pulse Shaping Without Amplification Before Stretcher After Stretcher Courtesy of Yuzhen Shen, Carlo Vicario, B. Sheehy, XJ Wang

6. Preliminary Laser Shaping Results with Thick BBO Xtal Courtesy of Yuzhen Shen, Carlo Vicario, B. Sheehy, XJ Wang

7. Shaping Results 12/14/04100 micron BBO Xtal Data compliments of Brian Sheehy and Henrik Loos

8. Flat Dazzler Filter

9. Dazzler Filter for Square Pulse

10. Streak Camera Results

11. Cross Correlation

12. Achieving Uniform Bunch Distributions using Flat-Top Laser Pulses @ Sumitomo SHI + FESTA Temporal distributions of shaped UV laser pulses by a X-ray streak camera Square pulse shape Gaussian pulse shape • The flatness of square-shaped laser pulse: 5~25% @ 4~14 ps FWHM • The fluctuation of shaped pulse length: 7% (pulse-to-pulse)@both shapes Courtesy of F. Sakai

13. Comparison of Our Shape with FESTA

14. Summary of December Dazzler Results • Measurements of pulse shape with all available instruments (monochromator, Streak camera, cross-correlator) conducted. • Agreement of 266 pulse shape and spectrum requires very careful alignment of laser beam (transverse temporal coupling). • Streak camera resolution insufficient to resolve < 2ps modulation in pulse shape. • Rise time of 3.5ps achieved w/o any phase correction. • Pulse length is 15ps. • Very good agreement between UV spectrum and cross-correlation.

15. Further R&D is needed to achieve desired shape!Propose continuing work at ANL and LLNLin parallel with laser procurement

16. Proposed ANL Work • Obtain reference data for conversion efficiency of second and third harmonic of IR laser light from a broadband TiS laser source • Compare these results to modeling predictions from the SNLO code • Assess the effects of shaping the incident IR transverse profile on the conversion efficiency and transverse profile of the third harmonic (UV) • Assess relay imaging of third harmonic light with a transversely shaped (non-Gaussian) profile over an extended transport distance and compare to modeling predictions from the ZEMAX code • Evaluate the performance of a reflective UV diffraction grating with respect to diffraction efficiency, anamorphic profile shaping and tilted amplitude front generation (time slew) and the UV fluence threshold for surface damage

17. Proposed LLNL Work • Perform R&D on techniques to produce temporally shaped UV pulses suitable for use in the LCLS injector. • Design, build and test laser diagnostics. • Test cathode launch optics with shaped pulses. • Provide (advise on) the beam steering stabilization system, which was developed by LLNL. • Support SLAC/LCLS in the drive laser vendor selection process and review of vendor’s work.

18. Laser Beam Shaping Work at LLNL • Continue the Dazzler shaping studies to improve the quality and reliability of the UV pulse and to explore other shape types. • Design a third-harmonic, non-linear optical system with more than 10% IR to UV conversion efficiency which uniformly converts over a 10 nm bandwidth. • Investigate designs which integrate shaping and conversion. In particular, the approach converting to UV with a short pulse and then stretching in the UV to the desired length deserves study. • Perform shaping studies using devices other than Dazzler. Shaping experiments using deformable mirrors and addressable LCD phase arrays are needed to aid in selecting the best technique. Investigate shaping techniques in the UV. • Operate the entire laser system with shaping and conversion at high repetition rate, up to 100 Hz. • Future: Design optical systems with the flexibility of producing arbitrary 3-dimensional pulse shapes.

19. Laser Diagnostics Effort at LLNL • Design, build and test diagnostic systems capable of measuring the IR, blue and UV wavelength-phase correlation (waveform) of the laser beam with better than 100 fs and 0.1 nm resolution. These diagnostics need to make these measurements for pulses as long as 20 ps and should be single-shot. • Design a system for measuring the shot-to-shot timing jitter between the laser UV pulse and the RF reference. The signals from these diagnostics should be compatible with the LCLS control system.

20. Additional LLNL Effort • Test the SLAC cathode launch prototype optics with temporally shaped UV pulses. • Support SLAC in the design of a beam stabilization system for the optical transport between the laser room and the cathode. • Review the drive laser proposals and write technical recommendations. • Participate in technical reviews.

21. Summary • First demonstration of temporal shaping of a UV pulse in a complete CPA Ti:Sapphire drive laser system plus frequency tripler using a Dazzler. • Verified large bandwidth (10 nm at IR wavelengths) significantly reduces IR to UV conversion efficiency. • LCLS laser design should pay careful attention to dispersive effects, including correlations between beam position and wavelength. • New laser diagnostics are needed, especially a high-resolution (less than 200 fs) device for measuring the wavelength-phase correlation of the laser pulses in the IR and the UV. • Propose R&D at ANL and LLNL.