Directional Emission of Multiply Charged Ions During Dissociative Ionization in Asymmetric Two-Color Laser Fields

Abstract

Intense, asymmetric $1\ensuremath{\omega}+2\ensuremath{\omega}$ laser fields are used to affect the directional ejection of multiply charged ion fragments from a variety of molecules, including ${\mathrm{N}}_{2}$, ${\mathrm{O}}_{2}$, CO, HBr, and ${\mathrm{CO}}_{2}$. By tuning the relative phase, $\ensuremath{\phi}$, between the two fields, we observe large forward-backward dissociation asymmetries. The largest asymmetries are obtained at the same values of $\ensuremath{\phi}$ for all species, suggesting a common dynamical mechanism. Following an independent phase calibration, the sign of the asymmetry appears to be opposite that expected from the standard enhanced ionization model.