Abstract: A measuring device completely determines the characteristics of light pulses in a beam of ultrashort light pulses using optoelectronic detectors instead of second harmonic generating crystals. An optical system provides a spatial dispersion of an ultrashort pulse in at least one dimension. A two slit filter intercepts the dispersed beam whereby the transmitted spectra combine to provide a beat frequency within selected limits. An optoelectronic detector detects the beat frequency and outputs a signal functionally related to the beat frequency that contains spectral phase information that is sufficient to characterize the pulse. In another embodiment, a beam splitter splits the beam into first and second beams, wherein one of the beams is time delayed and the other beam is spectrally dispersed. The two beam are recombined to provide information about the spectral phase of the ultrashort pulse. The pulse is completely characterized when the spectral phase information is combined with amplitude information.