Measurement of the ultrashort pulse spectral phase based on dispersive Fourier transformation.

A technique for measuring the spectral phase of an ultrashort pulse is developed based on the dispersive Fourier transformation method, as an alternative to spectral interferometric methods. The pulse spectral phase is measured by transferring the information from the spectral to the temporal domain by stretching the pulse to reach the far field of dispersion. We have implemented the technique through sum-frequency generation by using the laser pulse as a reference and have experimentally demonstrated the direct spectral phase measurement of various amplitude-modulated pulses.