Abstract: | The 2nd order volume autocorrelation technique, widely utilized in directly measuring ultra-short light pulses durations,
is examined in detail via model calculations that include three-dimensional integration over a large ionization volume, temporal
delay and spatial displacement of the two beams of the autocorrelator at the focus. The effects of the inherent displacement
to the 2nd order autocorrelation technique are demonstrated for short and long pulses, elucidating the appropriate implementation
of the technique in tight focusing conditions. Based on the above investigations, a high accuracy 2nd order volume autocorrelation
measurement of the duration of the 5th harmonic of a 50 fs long laser pulse, including the measurement of the carrier wavelength
oscillation, is presented. |