SIMULTANEOUS MEASUREMENT OF 2 ULTRASHORT LASER-PULSES FROM A SINGLE SPECTROGRAM IN A SINGLE-SHOT

Frequency-resolved optical gating (FROG) is a technique that produces a spectrogram of an ultrashort laser pulse. The intensity and phase of the ultrashort laser pulse can be determined through solving for the phase of the spectrogram with an iterative, phase-retrieval algorithm. This work presents a pew phase-retrieval algorithm that retrieves bot h the probe and the gate pulses independently by converting the FROG p hase-retrieval problem to an eigenvector problem. The new algorithm is robust and general, It is tested theoretically by use of synthetic da ta sets and experimentally by use of single-shot, polarization-gate FR OG. We independently and simultaneously characterize the electric fiel d amplitude and phase of a pulse (probe) that was passed though 200 mm of BK7 glass and the amplitude of an unchanged pulse (gate) from an a mplified Ti:sapphire laser. When the effect of the 200 mm of BK7 glass ; was removed mathematically from the probe, there was good agreement between the measured gate and the calculated, prechirped probe. (C) 19 97 Optical Society of America.