Studies of time-resolved harmonic generation in intense laser fields in xenon

We report preliminary experimental and computational studies of the temporal evolution of the harmonics, generated in xenon, by 50-ps pulses from a Nd: YLF laser, amplified in Nd: glass amplifiers, and focused to produce intensities in the range 1013--5 {\texttimes} 1013 W cm{\textminus}2. Measurements were made of the temporal profiles of the seventh- and ninth-order harmonics using a specially modified VUV streak camera with better than 7-ps temporal resolution. These results were compared with predictions of a numerical model that included the effects of neutral atom depletion and photoelectron dispersion in the calculation of the harmonic output as a function of time