title: Carrier-envelope-phase insensitivity in high-order harmonic generation driven by few-cycle laser pulses.
abstract: We present evidence for self-stabilization of the relative spectral phase of high-order harmonic emission against intensity variations of the driving field. Our results demonstrate that, near the laser focus, phase matching of the harmonic field from a macroscopic target can compensate for the intensity dependence of the intrinsic phase of the harmonics emitted by a single radiator. As a consequence, we show experimentally and theoretically the insensitivity of the harmonic spectra produced at the laser focus against variations of the carrier-envelope phase (CEP) of a sub-two-cycle driving field. In addition, the associated attosecond pulse trains exhibit phase locking against CEP changes of the few-cycle driver.
authors.forename: C
authors.initials: C
authors.lastname: Hernández-García
authors.forename: W
authors.initials: W
authors.lastname: Holgado
authors.forename: L
authors.initials: L
authors.lastname: Plaja
authors.forename: B
authors.initials: B
authors.lastname: Alonso
authors.forename: F
authors.initials: F
authors.lastname: Silva
authors.forename: M
authors.initials: M
authors.lastname: Miranda
authors.forename: H
authors.initials: H
authors.lastname: Crespo
authors.forename: I J
authors.initials: IJ
authors.lastname: Sola