Direct spectral phase measurement of femtosecond optical pulses by using multiple-slit interference

Recently, we developed a simple technique1 for measuring the spectral phase of femtosecond optical pulses, we called it direct optical spectral phase measurement (DOSPM). This technique measures the phase of the temporal interference between two frequency components selected by a movable double-slit mask in a zero-dispersion pulse shaper. Here we report a new method using a nine-slit mask that yields spectral phase measurement for eight spectral-frequency components with a single temporal scan.