An optical system configured for ultrashort laser pulse characterization, comprising: - means configured to introduce a controlled chirp, negative or positive, to an incoming ultrashort single laser pulse to be characterized; - a nonlinear optical medium, with normal or anomalous dispersion, through which said chirped ultrashort laser pulse is propagated in a direction, said nonlinear optical medium being configured to generate a nonlinear signal for all frequencies of the ultrashort laser pulse and to emit the generated nonlinear signal transversally to the propagation direction, wherein in case the nonlinear optical medium has normal dispersion the means comprises elements which introduce anomalous dispersion and in case the nonlinear optical medium has anomalous dispersion the means comprise elements with normal dispersion, and wherein as a result of said propagation: o different chirp values are introduced by the dispersion of the nonlinear optical medium itself in the ultrashort laser pulse at different propagation distances along the propagation direction in the nonlinear optical medium, and o a transverse nonlinear signal is generated in a direction perpendicular to the propagation direction from said ultrashort laser pulse having different chirp values introduced by the corresponding propagation distance within the nonlinear optical medium, said transverse nonlinear signal being a transverse second harmonic generation signal, TSHG; - analyzing means configured for recording a single-shot spectral image of said generated transverse nonlinear signal; and - a processing module comprising one or more processors configured for executing a numerical iterative algorithm to said recorded single-shot spectral image to retrieve the amplitude and phase of the electric field of the single ultrashort laser pulse, while the laser pulse duration range extends from a few-cycle regime to hundreds of femtoseconds. - means configured to introduce a controlled chirp, negative or positive, to an incoming ultrashort single laser pulse to be characterized; - a nonlinear optical medium, with normal or anomalous dispersion, through which said chirped ultrashort laser pulse is propagated in a direction, said nonlinear optical medium being configured to generate a nonlinear signal for all frequencies of the ultrashort laser pulse and to emit the generated nonlinear signal transversally to the propagation direction, wherein in case the nonlinear optical medium has normal dispersion the means comprises elements which introduce anomalous dispersion and in case the nonlinear optical medium has anomalous dispersion the means comprise elements with normal dispersion, and wherein as a result of said propagation: o different chirp values are introduced by the dispersion of the nonlinear optical medium itself in the ultrashort laser pulse at different propagation distances along the propagation direction in the nonlinear optical medium, and o a transverse nonlinear signal is generated in a direction perpendicular to the propagation direction from said ultrashort laser pulse having different chirp values introduced by the corresponding propagation distance within the nonlinear optical medium, said transverse nonlinear signal being a transverse second harmonic generation signal, TSHG; o different chirp values are introduced by the dispersion of the nonlinear optical medium itself in the ultrashort laser pulse at different propagation distances along the propagation direction in the nonlinear optical medium, and o a transverse nonlinear signal is generated in a direction perpendicular to the propagation direction from said ultrashort laser pulse having different chirp values introduced by the corresponding propagation distance within the nonlinear optical medium, said transverse nonlinear signal being a transverse second harmonic generation signal, TSHG; - analyzing means configured for recording a single-shot spectral image of said generated transverse nonlinear signal; and - a processing module comprising one or more processors configured for executing a numerical iterative algorithm to said recorded single-shot spectral image to retrieve the amplitude and phase of the electric field of the single ultrashort laser pulse, while the laser pulse duration range extends from a few-cycle regime to hundreds of femtoseconds.