Fig. 1
From: Attosecond recorder of the polarization state of light
Semi-classical sketch of the origin of the photoelectron asymmetry. The IR pulse is polarized along the k|| direction and the photoelectron asymmetry is measured along the k⊥ axis. The XUV pulse rotates counter-clockwise, the momentum distributions are observed at points α and β (green dots). The XUV-IR delay is set so that the IR vector-potential \({\mathbf{A}}_{{\mathrm{IR}}}(t)\), which streaks the electron, changes its sign when the attosecond XUV pulse releases the electron in the direction of positive k||, at time t2. At α, the path that contributes is that in which the photoelectron is ionized at time t1 and streaked in the positive k|| direction. Half XUV cycle later, when the photoelectrons are released in the negative k⊥ direction, the path that contributes to β is that in which the electron is ionized at time t3 and streaked in the negative k|| direction. The asymmetry between the distributions at α and β is sensitive to the degree of coherence and relative phase between the two orthogonal components
