Coherent control of the vibrational dynamics of aligned heteronuclear diatomic molecules

Abstract

We present an analytical pulse design protocol for controlling the vibrational dynamics of polar diatomic molecules within a given electronic state. Altering the potential energy function via the position-dependent electric permanent dipole moment, the vibrational state population dynamics is directly controlled using appropriately shaped laser pulses in the midinfrared regime. The optimal pulse shapes---that are expected to drive the molecule along user-defined quantum pathways---are obtained by reverse engineering, that is, solving the Schr\"odinger equation of the nuclei inversely in a relevant subspace. The proposed control scheme is validated by accurately solving the full time-dependent Schr\"odinger equation of the ${\mathrm{HeH}}^{+}$ molecular ion with two completely different methods: (1) propagating the complex population amplitudes of many field-free eigenstates or (2) propagating directly the nuclear wave packet on a grid. We find that besides smooth transitions, arbitrary Rabi oscillations as well as vibrational ladder climbing can be efficiently controlled with the present scheme. As a result, the molecule is successively excited beyond the potential barrier, leading to enhanced dissociation in the ground electronic state. Rotational effects and possible extensions of the presented control are also briefly discussed.