Exploration and Control of Molecular Dissociation in Strong Asymmetric Laser Fields

Intense lasers can be effective tools for manipulating and probing coherent dynamics within atoms and molecules. Asymmetric laser fields, in which there is a pronounced, controllable difference in the peak amplitude in one direction over another, are particularly interesting in this regard. Such fields can be produced through carrier-envelope-phase stabilization of few-cycle laser pulses or by coherently combining even and odd harmonics of a laser pulse (e.g. with frequencies $\omega$ and 2$\omega)$. We have used such fields to explore asymmetric dissociation of multiply-charged homo- and hetero-nuclear diatomic and triatomic molecules. Robust high-contrast control over the emission direction of specific ion fragments is observed for target species with a variety of different molecular structures, suggesting a common dynamical mechanism. The phase, intensity, and pulse-duration dependence of the directional emission could provide new insight into the combined nuclear and electronic evolution, from the initial ionization step through expansion and subsequent ionization.