Time-domain interferometry for direct electric-field reconstruction by use of an acousto-optic programmable filter and a two-photon detector

The characterization of femtosecond optical pulses based on two-photon detector and a pulse shaper consisting of a longitudnal acousto-optic programmable filter was presented. The pulse shaper was used to add a known amount of second-order spectral phase to the incident beam. The spectrum obtained from the two-photon detector was found to be identical to the frequency-shifted spectrum obtained from the two-photon measurement.