Light Control of Nuclear Motions by Vortex Electron Localization

Light fields are hard to directly affect nuclei in strong-field ionization of molecules and therefore the molecular ion generally dissociates according to the geometrical configuration at the ionization instant. In this work, we observe a counter-intuitive electron-proton angular correlation and proton vortices in strong-field ionization of H$_2$ molecules by bi-circularly polarized two-color laser fields. These phenomena can be explained by the pathway interference and localization of the remaining electron in H$_2^+$ with different angular momenta mediated by the tail of laser fields and are validated by a quantum simulation including both electrons and nuclei, as well as by a semi-classical trajectory model which clarifies the phase of the electron-nuclei coupled wavepacket in laser fields. Our joint experimental and theoretical study provides a general picture on the control of molecular bond breaking by laser fields in two dimensions.