Laser pulse shaping Since the last meeting Lab

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

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

First rectangular spectrum in 3° harmonic 3 w trise-time (2. 3 ps stretcher 1 ps) DW 3 > constant (tmin < 1 ps) this is not a problem DW 3 < DWcrystal (we have to reduce the spectrum width in 1° harmonic)

Cross Correlation measurements theory w t

Spatial chirp -0. 7 nm grating x 3 w grating +0. 7 nm

Spatial chirp and cross-correlation 10 ps 1° 3° 3. 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 Autocorrelation Spectrum before and after mask Beam profile after mask

Beam profile (far field) vs chirp 0 -250 -500 X (mm) -750 -1000 -1500 -2000 -2500 4 F-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 4 F-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 Appendix A 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

Amplifier phase function stretcher Appendix B compressor amplificatore compressor

Dazzler amplitude modulation vs chirp Appendix C