We show theoretically and confirm experimentally that, by propagating a frequency-swept ultrashort pulse through an ensemble of two-level systems, it is possible to measure the time-dependent relative phase of the pulse with respect to that of the impact-excited oscillating resonant polarization. The phase is obtained from the intensity modulation of the pulse as measured by a cross-correlation technique.
© 1985 Optical Society of America
Joshua E. Rothenberg and D. Grischkowsky, "Measurement of the phase of a frequency-swept ultrashort optical pulse," J. Opt. Soc. Am. B 2, 626-633 (1985)