1. LAB-LASER MILANO
Pulse shaping
Sparc meeting october 4th 2004

2. OUTLINE
Nd:YAG laser state
Laser-fiber coupling
Pulse “deformation” in BBO crystal
Improved shaper design

3. 1- Laser as tool for pulse shaping tests
Two weeks ago the laser reached the
Project features
100 ps pulse length
Amplitude and time stability (few %)
100 MHz operation
2 W output power (20 nJ/pulse)

4. Now we know in any detail
the physics and the technology of each optics inside the laser
The subtle connections between the optics and the mode-locked physics of the laser

5. Laser Nd:YAG

6. Next on the laser
A play for the best trade-off between the pulse length and the pulse energy
The implementation of the SESAM technolgy for a real reduction of the pulse length

7. The coupling in the optical fiber
Succesful
The ½ km fiber did not arrived in time for this meeting, but ……..

8. We have solved the listed problems
Injection power control
Injection optical system
Home made beam profiler

9. Accoppiamento fibra
450 mW (30%)

10. Spectrum acquisition We have Set the hardware Developed the software
We need a phtotomultiplier for the routine operation

11. Acquisizione spettro

12. Pulse “deformation” in BBO crossing for harmonic generation
We have investigated the effect of the non-linearities in crossing the crystal as function of beam intensity

15. observations
At intensity technically possible the deformation seems negligible/manageable
The request on the alignement is just at the limt with BBO crystal
The ramp could be found simply rotating the crystal but… a problem with rise time

16. Possible up-grading of the shaper
configurartion
From a cross-fertilization of different fields in letterature
The hardware is simpler
With
More software

17. Vecchio progetto

19. To get the profile of the output pulse

20. What Next
Shaping of the first harmonic
Investigating the non-linearities on the pulse shaping in amplifiers, harmonic generations both in BBO and KDP
Test of the pulse shaping with feedback with first harmonic
Development of a regenerative amplifier for testing the shaping system with the second harmonic
Setting for the third harmonic shaping and the relative tests

21. This program needs
Some investment on hardware

22. Time schedule
We should start hopefully next week the work with the pulse shaping with the first harmonic
We belive/hope to write the first experimental article testing a piece of the published theoretical work for the end of the year.
We cannot say more for the next-next because we do not know what is in front of us.

23. Robust photocatodes-SFERA program
The experimental result is definitely important
QE = 3·10-4
Low field 1 MV/m
We are organizing for a test in a
rf-gun

24. THE END

25. d = modulation amplitude
fm = mode locker frequency
D f = gain bandwidth