title: Duration of ultrashort pulses in the presence of spatio-temporal coupling.
abstract: We report on a simple method allowing one to decompose the duration of arbitrary ultrashort light pulses, potentially distorted by space-time coupling, into four elementary durations. Such a decomposition shows that, in linear optics, a spatio-temporal pulse can be stretched with respect to its Fourier limit by only three independent phenomena: nonlinear frequency dependence of the spectral phase over the whole spatial extent of the pulse, spectral amplitude inhomogeneities in space, and spectral phase inhomogeneities in space. We illustrate such a decomposition using numerical simulations of complex spatio-temporal femtosecond and attosecond pulses. Finally we show that the contribution of two of these three effects to the pulse duration is measurable without any spectral phase characterization.
authors.affiliation: Laboratoire Charles Fabry, Institut d'Optique, CNRS, Univ Paris-Sud, Palaiseau, France. charles.bourassin-bouchet@institutoptique.fr
authors.forename: C
authors.initials: C
authors.lastname: Bourassin-Bouchet
authors.forename: M
authors.initials: M
authors.lastname: Stephens
authors.forename: S
authors.initials: S
authors.lastname: de Rossi
authors.forename: F
authors.initials: F
authors.lastname: Delmotte
authors.forename: P
authors.initials: P
authors.lastname: Chavel