1. Summary Timing and Diagnostics 1 Franz X. Kärtner and 2 Steve Jamison 1 CFEL - DESY and MIT, 2 Daresbury

2. 2 CW / Pulsed Timing Distribution and Synch. fs x-ray pulses MIT- DESY Pulsed LBNL Cw- Laser Timing Stabilized Optical Fiber Links

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4. 4 Pulsed Timing-Stabilized Fiber Links PZT-based fiber stretcher Mode-locked laser Fiber link ~ several hundreds of meters to a few kilometers isolator Balanced Optical Cross Correlator Faraday rotating mirror Cancel fiber length fluctuations slower than the pulse travel time (2nL/c). 1 km fiber: travel time = 10 μs  ~100 kHz BW

5. 5 Other Implementations Pulsed FLASH @ DESY European XFEL planing PAL in prototype phase CW LCLS @ SLAC XPS @ APS NGLS planing

6. 6 FERMI CW Transmitter Electron bunch arrival time measurement Drive KLY3 unstable

7. 7 5.3fs RMS in 10 days

8. 8 Towards sub-fs systems

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10. 10 Jungwon Kim, KAIST: Sub-100 attosecond Ultrafast Lasers

11. Ti:sapphire Laser Jitter ~ 13 as 11 A. Benedick, et al. Nat. Photonics 6, 97-100, 2012

12. 12 Timing To Do List  Urgent need in engineered implementation of sub-10fs systems in accelerator laboratories with many > 10’s of links. - systematically eliminate free space sections and components - all fiber implementations avoiding unintended reflections - integrated optical components, plug and play - develop a true timing technology base suited for modulator implementations in accelerator facilities  Open issues for sub-systems operating at low-repetition rate: characterize drifts of amplifiers and how to compensate for it characterize intra pulse train drifts and how to compensate for it  Ultimately single shot X-ray – optical cross correlator to eliminate critical drifts at the output  Ongoing work is concentrated on pushing the timing precision towards the sub-fs scale in laboratory experiments

13. Bernhard Schmidt, DESY Diagnostics – longitudinal profile

17. Measured Spectrum -> temporal profile. Retrieval of missing phase info through Kramers-Kronig Much discussion on feasibility of retrieval - Sceptics converted by real data demonstration - only possible through thorough calibration -..caveats/pitfalls & puzzles still remain Discrepancies: real beam effects (?)

18. Online bunch profile available for FLASH operators....

20. Prospects of EO as “facility ready” systems...? Current time resolution ~1 ps potential improvement to 100fs (state of art) with data deconvolution..

21. Do we need explicit time information...? Upconvert bunch form factor to an optical spectrum Potential for robust all-optical diagnostic - simple/robust ns laser Discussion on whether the phase information could be experimentally retrieved. Yes, probably... With reintroduction of modest complexity (another laser!)

22. Time explicit diagnostics Many challenges need to be overcome together to break the 100fs “barrier” in resolution -Materials issues -Bandwidth currently ~ 10THz. Want ~50THz bandwidth! -Potential solutions in new materials, or in multi-crystal detectors - optical characterisation issues - FROG concepts for sub (optical) pulse duration characterisation - phase retrieval at low pulse energy.. - splicing of multi-crystal detectors

23. Wider diagnostic challenges (no claim to be comprehensive!) High dynamic range imaging - “halo” & high current machines. - high repetition rate laser wire as potential solution Ultrafast Photon diagnostics (arrival / duration) - (soft-xray ) – attosecond laser technique; other? - hard xray. Via electron beam diagnostics (energy loss). Other? Laser-plasma diagnostics – almost everything challenging! - ~1 fs duration - Emmittance - Energy spread - slice parameters !!!? But some nice results coming out (duration through faraday effect in plasma) Users and operator availability vs. “Diagnostics-by experiment” -

24. Summary Timing and Diagnostics Thank you to speakers and workshop organizers