Single shot complete characterization of femtosecond laser pulses employing self-phase modulation

We propose a new single shot technique for reconstructing femtosecond pulses utilizing self-phase modulation. The principle of the technique is analyzing multiple spectra belonging to the same pulse but nonlinearly modulated with different intensity levels. The variety of intensities is well defined and obtained from the spatial distribution of the beam. The technique needs no prior information about the pulse and can be implemented by focusing the beam in any thin nonlinear medium and measuring the resulting spectrum by an imaging spectrometer. The fidelity of the technique has been proven with numerical examples including simple and complicated cases and in the presence of noise.