Single-shot autocorrelator for KrF subpicosecond pulses based on two-photon fluorescence of cadmium vapor at lambda = 508 nm.

By excitation of cadmium vapor with a high-peak-power KrF excimer laser pulse, fluorescence of an atomic transition at lambda = 508 nm is induced by a two-photon ionization process followed by fast recombination. The nonlinear response of the medium is used to develop a simple single-shot autocorrelator for subpicosecond KrF excimer laser pulses operating down to intensities of less than 10(9)W/cm.(2) We have measured 360-fs (FWHM) pulses at lambda = 248 nm with a time resolution of 15 fs.