  We investigate differential electron distributions in nonsequential double
ionization (NSDI) with linearly polarized, few-cycle pulses, using a classical
model based on a laser-assisted inelastic $(e^-,2e^-)$ rescattering mechanism.
We show that these yields, as functions of the momentum components parallel to
the laser polarization, are highly asymmetric, and strongly influenced by the
absolute phase, i.e., the phase difference between the carrier oscillation of a
few-cycle laser pulse and its envelope. Indeed, around a critical phase, such
distributions change their sign in a radical fashion. This phase dependence
provides a possibility for absoute-phase measurements which is, in principle,
superior to the schemes involving high-order harmonic generation or
above-threshold ionization.
