Measurement of the duration of high harmonic pulses

Summary form only given. High harmonics are generated during the ionization of an atomic gas and therefore the probability of ionization, the number of unionized atoms, and the phase matching effects will impose a natural temporal envelope on the harmonic generation. We made some simulations which showed the maximal, minimal, and averaged possible values of the intensity of the harmonic as a function of the angular frequency detuning multiplied by the length of the harmonic pulse. From the envelope of the maximum signal we can extract the high harmonic pulse duration.