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 16-11-2005

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-04-01-2004) S. Cialdi, I. Boscolo, Nuc. Inst. Meth. A 538, 1-3 (2005) 1-7 - 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

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

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

Cross Correlation measurements theory w t

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

Spatial chirp and cross-correlation 10 ps 1° 3° 3.6 ps 6 ps 2°

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

SFERA Lab. Milano

New spectrometer

New beam profiler – far field

New beam profiler – after LCM

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

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

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.

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

Amplifier phase function stretcher compressor amplificatore stretcher compressor Appendix B

Dazzler amplitude modulation vs chirp Appendix C