Characterization of sub-6-fs optical pulses with spectral phase interferometry for direct electric-field reconstruction

We demonstrate spectral phase interferometry for direct electric-field reco nstruction (SPIDER) as a novel method to characterize sub-6-fs pulses with nanojoule pulse energy. SPIDER reconstructs pulse phase and amplitude from a measurement of only two optical spectra by use of a fast noniterative alg orithm. SPIDER is well suited to the measurement of ultrabroadband pulses b ecause it is quite insensitive to crystal phase-matching bandwidth and to u nknown detector spectral responsivity. Moreover, it combines highly accurat e pulse-shape measurement with the potential for online laser system diagno stics at video refresh rates. (C) 1999 Optical Society of America. OCIS cod es: 320.0320, 320.5550, 320.7100, 120.5050, 120.3180.