Spectral phase reconstruction of femtosecond laser pulse from interferometric autocorrelation and evolutionary algorithm

We report on the complete temporal characterization of femtosecond laser pulses from second-order in-terferometric autocorrelation and laser spectrum measurements. The method exploits a newly developed autocorrelator based on a two photon-absorption signal produced directly within a camera sensor so as to provide a single-shot interferometric autocorrelation of great reliability and robustness. Interferometric autocorrelation trace and laser spectrum are exploited for a spectral phase retrieval via an evolutionary algorithm. The quality of the reconstruction for highly modulated spectral phases imprinted by a pulse shaper confirms the reliability of the method. The autocorrelator is compact, robust and easy to use. Possible improvements are discussed.