Measuring the initial phase of few-cycle laser pulses through few-photon ionization

In view of recent experimental developments and interest, we evaluate the possibility of measuring the absolute phase of a short laser pulse via the asymmetry in the angular distribution of the electron emission. On the basis of quantitative calculations of the ionization of Cs, we demonstrate that the asymmetry is directly related to the initial phase of the field. Our results show that this approach may turn out to have some experimental advantages.