Influence of Noise Distortions of the Spectral Phase on the Profile of an Ultrashort Pulse

Based on numerical and experimental studies, an analysis of the influence of the noise component in determining the spectral phase of an ultrashort pulse in the problems of reconstructing the pulse profile was carried out. Additive white noise was considered and it was shown that the error in field reconstruction becomes proportional to the product of the spectral amplitude and the error in determining the spectral phase at small values of the latter. The results obtained are applied to the technique of determining the spectral phase based on the dispersion Fourier transform. The high accuracy of the method and the possibility of its use as an effective technique were discussed. The spectral phases of double-peak pulses formed from a 120 fs laser pulse with a known spectral phase were experimentally determined, and the error in determining the spectral phase and reconstructing the pulse field was assessed.