Abstract

Recently it was shown that by superimposing a linearly polarized fundamental with its second harmonic in orthogonal polarization one can obtain re-collisions that sweep over a large range of angles during a short time [1]. Harmonics from such a re-collision will not only be emitted in a short burst, but also their polarization will rotate rapidly during the pulse. The rotation of the polarization plane encodes the rapid variation of the electron incidence angle on the parent ion. With that, in addition to time and high harmonic frequency, which are connected to re-collision time and energy, respectively, the polarization angle of the harmonic radiation provides a third dimension of observation in re-collision based experiments.

© 2007 IEEE