Study of asymmetric electron emission in two-color ionization of helium (XUV-IR)

Abstract

In this work, we focused on the angular photoelectron emission from helium generated by an Attosecond Pulse Train (APT) in the presence of a weak Infrared (IR) field. The APT creates both an excited and a continuum electron wave packets. By ionizing the excited state with the IR pulse, a delayed new continuum electron wave packet is created. Consequently, a mix of energy-degenerate even and odd parity states is fed in the continuum by one- And two-photon transitions. These interfere, leading to an asymmetric electron emission along the polarization vector. The interference can be controlled by varying the time delay between the APT and IR pulses. © Springer-Verlag Berlin Heidelberg 2012.