Autoresonant excitation and control of molecular degrees of freedom in three dimensions

A classical, three-dimensional analysis of excitation and control of vibrational-rotational degrees of freedom of a polar diatomic molecule by chirped laser field is presented. The control strategy is based on autoresonance (adiabatic nonlinear synchronization) phenomenon, in which the molecule automatically adjusts its state for staying in a persistent resonance with the laser field despite variation of the laser frequency. Thresholds on driving field amplitudes for entering the autoresonant excitation regime by passage through different resonances are calculated. In autoresonance, the molecule can be excited to large energies and approach the dissociation limit by substantially weaker laser fields than with constant-frequency drives.