Orientational Dichroism in the Electron-Impact Ionization of Laser-Oriented Atomic Sodium

Abstract

We report the first experimental observation of ``orientational dichroism'' in electron impact-induced ionization. $(e,2e)$ experiments have been performed on pure angular momentum states ${3P}_{3/2}$, ${m}_{F}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}+3$ and ${m}_{F}\phantom{\rule{0ex}{0ex}}=\phantom{\rule{0ex}{0ex}}\ensuremath{-}3$ of the sodium atom, excited by right- and left-handed circularly polarized laser light. Our results show that the angular correlation of the final-state electron pair is strongly dependent on the ${m}_{L}$ sublevel populated. Comparison with calculation demonstrates the dependence of the dichroism on details of the scattering dynamics.