1. SPARC Review Committee 16-11-2005
Laser pulse shaping
Since the last meeting – (Lab. SFERA MILANO results [S. Cialdi, F. Castelli,
I. Boscolo])
Theory and simulation program of the rectangular pulse deformation in the third harmonic generation (previous time we were at the second harmonic generation) - Rectangular pulse formation in a laser harmonic generation, S.Cialdi, F. Castelli, I. Boscolo, Report INFN-BE-05-1 (2005), in press. on Appl. Phys. B
We have built a diagnostic tool to investigate the spatial and spectral deformations introduced by the pulse shaping and laser components (spatial e spectral deformation due to the pixellation of the LCM)
SPARC Review Committee

2. Work in Frascati Lab
The theory of the rectangular profile at the 2° and 3° harmonic generation developed in Milano has been applied for the generation with the DAZZLER – A shaper for providing long laser waveforms (Report INFN/BE ) S. Cialdi, I. Boscolo, Nuc. Inst. Meth. A 538, 1-3 (2005) Rectangular pulse formation in a laser harmonic generation, S.Cialdi, F. Castelli, I. Boscolo, Report INFN-BE-05-1 (2005), in press. on Appl. Phys. B
The theory and the relative simulation program have shown to be very useful for achieving experimentally the searched pulse waveform
The high resolution spectrum analyzer developed in Milano has been reproduced in Frascati and has shown to be efficient for our needs

4. 2w 3w Comparison between theory and experiment a=12400 fs2 a=52400 fs2
Amplifier
Dazzler

5. First rectangular spectrum in 3° harmonic3w
stretcher
trise-time (2.3 ps ps)
DW3 > constant (tmin < 1ps) this is not a problem
DW3 < DWcrystal (we have to reduce the spectrum width in 1° harmonic)

6. Cross Correlation measurements
theory w t

7. Spatial chirp
-0.7 nm
+0.7 nm
grating x 3w
grating

8. Spatial chirp and cross-correlation
10 ps 1° 3°
3.6 ps ps 2°

9. Spatial chirp removal
2° harmonic
3° harmonic
1° harmonic

10. SFERA Lab. Milano

11. New spectrometer

12. New beam profiler – far field

13. New beam profiler – after LCM

14. Autocorrelation – spectrum – beam profile after mask vs chirp
Spectrum before and after mask
Beam profile after mask
Autocorrelation

15. Beam profile (far field) vs chirp
-250
-500
-750
X (mm)
-1000
-1500
-2000
-2500
4F-SPARC
-3000

16. Considerations
Rise time: 1° harmonic spectrum width (future: feedback)
Spatial chirp: double passage stretcher (improve the THG efficiency)
The refinement of the simulation program for the 3° harmonic generation is in progress
The 4F-LCM project is defined and the spectral-temporal-spatial deformation due to the pixels of the LCM are under control
Milano has fullfilled all the workpakages discussed at the starting of the collaboration.
With the tecnological apparatus of the SFERA Lab we have reached the roof of the pouposes.

17. 2° and 3° harmonic generation
Rectangular pulse formation in a laser harmonic generation, S.Cialdi, F. Castelli, I. Boscolo, Report INFN-BE-05-1 (2005), in press. on Appl. Phys. B
Appendix A

18. Amplifier phase function
stretcher
compressor
amplificatore
stretcher
compressor
Appendix B

19. Dazzler amplitude modulation vs chirp
Appendix C