Pump-probe. probe optical laser systems at FLASH. S. Düsterer

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Melvin Shaw
5 years ago
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1 Pump-probe probe optical laser systems at FLASH S. Düsterer

2 Outline Current status of the laser systems ( what is working) Planned upgrades till spring 2010 ( what will be working) The future. Lasers from users

3 Laser usage frequency of laser usage in % Jan 06 Jun 06 Sep 06 Nov 06 Jan 07 Mrz 07 Nov 07 Feb 08 Mrz 08 Jun 08 Aug 08 Okt 08 Dez 08 Feb 09 Apr 09 Flash usertime from Jan Apr 2009

Optical Pump-probe laser system Pulsetrain laser by MBI 20 µj/pulse, 120 fs, 800 nm Burst mode: 800 pulses@1mhz with

4 Optical Pump-probe laser system Pulsetrain laser by MBI 20 µj/pulse, 120 fs, 800 nm Burst mode: 800 with 5Hz RF- synchronized GHz) fs oscillator Commercial (Coherent Hidra) 10 Hz, < 25 mj, 110 fs, 800nm system Experiment

5 Layout in the experimental hall BL3 BL2 BL1 PG2 PG1 visible laser light

6 The Laser at the experiment Laser beamline ends ~ 50 cm sideways and back relative to the FEL focus with window flange Laser at the experiment has to be shielded! Our mobile laser hutch Advanced interlock 3x4 m 3 m height Encapsulate the setup completely (cameras, remote control, )

7 Laser hutch

8 Hidra

9 Current parameters Burst mode laser: 100 khz to 1 MHz, 800nm, ~ 20 µj, 120 fs, ~ 10 mm FWHM (~3 mm at BL1), M 2 < 2 10 (5) Hz mj laser : 1-2 mj, 800 nm, 110 fs, ~15 mm FWHM (~ 4 mm at BL1), M 2 < mj, 800nm, 4 ps (recompressed at experiment to 110 fs) Remote control via DOOCS + Labview option delay ns (<10 fs res.) attenuate 100%-1% rotate polarization S. Huber

10 Laser remote control in DOOCS

11 Timing current situation Short term jitter 500 fs FWHM -> TEO Drifts: <1ps - 5 ps /h -> streak camera

12 Drifts : Streak camera fs-laser to the experiment and to the streak camera visible radiation from the bending magnet to streak camera

Long-term Timing Less than 10 ps drift in a week (best ever ) Less than 1 ps rms per day (best ever ) 3 0.

13 Long-term Timing Less than 10 ps drift in a week (best ever ) Less than 1 ps rms per day (best ever ) ps rms / 12 h 2 difference FEL - laser in ps -48 jitter in ps hours Input for delay line week

14 Jitter: Timing Electro-Optical Sampling pump-probe fs-laser for FEL-experiments TEO Experiments laser EO-Crystal polarizer E r electrons v camera

15 Electro-Optical Sampling principle polarizing beam splitter time +10ps time; space k v laser v k p polarized ICCD camera time -0 integrated intensity -10ps Arrival time and duration of bunch is encoded on profile of laser By A. Azima

16 TEO works With TEO Averaged scan 200fs steps, 500 spectra By A. Azima, DESY

17 Timing Electro Optical sampling Shot to shot timing information up to 100 fs resolution TEO is an advanced, data intense, complicated setup! TEO has to be well coordinated with the laser team Available for pump-probe experiments BUT only for dedicated scans (1-2 h) (currently) Data available AFTER the experiment

18 Planned (envisioned) Upgrades during 2009 TOPAS: deliver ~ 2µm to 260 nm (few to 300 µj, 100 fs, 10 Hz) Pulse shortening (100 fs -> 30 fs) Pulse train laser ~ 50 µj/ pulse Extend motorized delay to > 8ns Single-shot option Amplify optical clock pulses instead of fs-oscillator BAM stabilize timing within pulse trains TEO online + increased availability

19 Beam Arrival-time Monitor Idea: Stabilization of the electron bunch arrival time to few 10 fs Demonstration: Correlation width < 10 fs rms F. Löhl, proceedings (TUPC 135) EPAC 2008

20 Shorter pulses Approach shorten the amplified 100 fs pulses Nonlinear optics (cascaded chi 2) Filamentation ( collaboration with MBI, AG Steinmeyer) Norm. intensity (a.u.) Kr 920 mbar compressor position x64 grid 128x128 grid 256x256 grid before filament Time (fs)

21 The future Next generation burst mode laser HHG-Seed laser Pump-probe Laser ( also for XFEL) Pulse energy > 1 mj Rep rate: MHz Wavelength 800 nm Pulse duration < 7 fs By F. Tavella

22 Laser from User Lasers of class 3 and 4 have to be announced at least 2 weeks before arrival at FLASH (to S. Düsterer or H. Redlin) Setups have to be completely optically sealed FLASH provides: 5 Hz trigger (~1 ns jitter) 1.3 GHz, 108 MHz, 81 MHz, 9 MHz (upon request)

23 Laser administrative We would like to meet with all groups using the optical laser ~ 2 month before the experiments The Laser team: Harald Redlin (Burstmode laser, ) Nikola Stojanovic (TEO, ) Franz Tavella (few cycle burstmode, ) ( )

24 Questions?

Synchronization and pump-probe experiments

Synchronization and pump-probe experiments by Stefan Düsterer Outline o Pump-probe probe infrastructure VUV + VUV VUV + optical o o Temporal overlap and jitter As example: the pump-probe probe chamber