1. Injector Drive Laser Update
Sasha Gilevich
May 11, 2005
Project Status
Drive Laser Procurement
R&D
Response to Recommendations

2. Project Status
The vendor for the Drive Laser is selected. Purchasing is working on the award of the contract.
Four bids for the S20 drive laser facility were received. Bids are being analyzed.
Requirements to the Laser PPS are defined. Standard Procedure for Safe Laser Operation is written. Design of the PPS is done. Debug is in progress.
Design of the transport tubes done; drawings submitted for the quote.
Design of the Launch and Conditioning System is near completion
R&D effort is defined and started.
LCLS performs shaping & UV conversion R&D with other labs (LLNL, ANL)
BNL temporal shaping work with Dazzler completed

3. Drive Laser Procurement Process
Drive Laser Technical Review
July 21, 2004
Evaluate RFI & Technical Review Responses
Write Request for Proposal (RFP)
Write Request for Information
(RFI)
Write & Approve
Advance Procurement Plan (APP)
Submit RFP to Vendors
Receive the proposals
Evaluation & Technical Committees Review the Proposals
Evaluation Committee Ranks the Proposals
Evaluation Committee Selects Vendor
SLAC Awards Contract
Site Visit

4. Drive Laser Procurement
Responding to the RFP 5 proposals were submitted
Toptica Photonics

5. Drive Laser Vendor Selection
Thales
Strengths
High potential output IR energy (80mJ system at ALLS)
Manufacturer of the QCW DPSS pump laser (Jedi)
Used Dazzler in several systems (to get a flat phase after RGA)
Proposed configuration can be upgraded to higher energy (up to 50mJ) by adding second Jedi pump.
Cryo cooling is not needed, but can be added
Aberration-free stretcher (patented).
Provides programmable, multi-channel pulse synchronization unit.
Short delivery time (8 months)
Thales is a part of a very large French defense contractor

6. Architecture of Proposed Thales Laser System
150ps
80mW
119MHz
119MHz
400mW
Femtolasers Oscillator
Femtosource Scientific 20s
(chirped mirrors)
1.5mx3.75m footprint
(~4.5’x11.5’)
Stretcher
DAZZLER
20 mJ, 120 Hz
5W, 119MHZ
RGA
Regen Amp
Spectra Physics
MILLENIA Vs
1mJ, 120Hz
10%extraction
25-30 RT
JEDI #1
100 mJ,120 Hz
Pre-Amp
4-pass Bowtie
Amplifiers are not cryo-cooled
IR stability <1%rms (short term)
80 mJ, 120 Hz
>20mJ, 120Hz
25%extraction To
cathode
Amplifier
2-pass Bowtie
Compressor
THG
JEDI #2
100 mJ,120 Hz
>2.5mJ, 120Hz
10%efficiency
>25mJ, 120Hz
90%eff/pass
>40mJ, 120Hz
25%extraction
100 mJ, 120 Hz
Courtesy of Dave Dowell

7. Pump Laser - JEDI
Thales
The JEDI is the only DPSS laser at 100 Hz available on the market. It has been specially designed to efficiently pump 100 Hz Ti:Sa amplifiers
JEDI laser uses 3 FLINT QCW chambers in oscillator-amplifier configuration. This ensures a very good beam quality and high stability (<1% rms).
Lifetime of the QCW diodes more than 2x109 shots

8. Open Issues UV shaping part is not developed
No details on special diagnostics
Controls interface
R&D Plan
Conduct UV shaping R&D (LLNL)
Develop special diagnostics (LLNL)

9. BNL/SLAC/INFN Laser Pulse Shaping
Dazzler - FastLite Inc.
acousto-optic dispersive filter
(P. Tournois et al.)
acoustic wave (computer programmable)
- spectral amplitude
- temporal phase
TeO2 crystal
Dazzler in DUVFEL Drive Laser
Courtesy of Dave Dowell and
Yuzhen Shen, Carlo Vicario, B. Sheehy, XJ Wang

10. Results Show Difficulty of Producing & Measuring Square UV Pulses
Comparison of UV Pulses in Streak Camera, Cross Correlator and Spectrum
Streak Camera Measurements
at 3-wavelengths

11. Summary of the BNL Experiments
Laser shaping
Reliable flat-top shape of IR spectrum with iterative Dazzler amplitude filter.
Thin crystals preserve the 10nm BW in UV conversion, but efficiency only 5%.
Flat-top UV spectrum with <10% modulation achieved for 15ps pulse.
UV pulse rise time of <1ps achieved.
Issues
Meet the pulse length of 10ps, rise time of 1ps, and flat-top requirement simultaneously.
Phase control required to achieve temporal flat-top in UV.
Kerr-effect in regen creates phase distortions from amplitude modulations.
Fluctuations in amplifier gain make control of phase distortions difficult.
Single shot temporal diagnostics with high resolution required.
Laser amplifier stability important for temporal shape stability.
Further R&D is needed
Courtesy of Henrik Loos

12. Laser Beam Shaping Work at LLNL (April 2005 – January 2006)
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.
Modeling
Integrated model including temporal shaping and UV conversion. Optimize UV conversion efficiency
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
Experiments
IR and blue shaping
Test and optimization of the UV conversion. UV shaping

13. Laser Diagnostics Effort at LLNL (April – October 2005)
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.

14. LLNL Work - Summary
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 in the Drive Laser integration.
Participate in the technical reviews of vendor’s work.
Support integration of shaping into the drive laser

15. ANL Work UV Conversion and Spatial Shaping
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

16. Response to Recommendations
Conduct a detailed review of the photo-gun drive laser with a panel of laser experts
Technical Committee of the outside laser experts participated in the Drive Laser Review (June, )
Technical Committee gave recommendations on the RFP and evaluated the proposals.

17. Response to Recommendations
Perform a complete set of risk reduction experiments on pulse frequency conversion with shaped pulses using the capabilities at BNL
Experiments were performed May – December 2004
The results of the experiments helped in the Laser vendor selection:
Dazzler is the right technology for the pulse shaping
Having the headroom in the IR power is important
Stability of the amplifier operation is important

18. Response to Recommendations
Aggressively seek to hire a laser technology team to oversee all laser activities
Laser group leader was hired
Greater involvement by laser scientists from LLNL should be sought
LLNL conducting R&D work for the project
LLNL scientists participate in the Drive Laser procurement and integration process.