Measurement of the subcycle timing of attosecond xuv bursts in high-harmonic generation
The absolute timing of the high-harmonic attosecond pulse train with respect to the generating IR pump cycle has been measured for the first time. The attosecond pulses occur 190±20 as after each pump field maxima (twice per optical cycle), in agreement with the “short” quantum path of the quasiclassical model of harmonic generation.