Reconstruction of the time profile of femtosecond laser pulses through cross-phase modulation

Experimental results concerning the determination of the time profile of femtosecond laser pulses are presented. The method is based on the analysis of the changes of the laser spectrum induced at different delays by cross-phase modulation. Pulses from a 30-fs Ti:sapphire laser at 800 nm are characterized over a high dynamic range. Second-harmonic pulses at 400 nm from the same laser are also characterized, exhibiting the expected improvement in contrast ratio.