All-optical three-dimensional orientation of asymmetric-top molecules with combined linearly and elliptically polarized two-color laser fields

We propose an approach to the realization of all-optical three-dimensional molecular orientation, in which a linearly polarized fundamental pulse and an elliptically polarized second-harmonic pulse with one of the polarization axes parallel to the linear polarization of the fundamental pulse are employed to orient asymmetric-top molecules, leading to higher degrees of orientation. In addition to the one-dimensional orientation realized along the linearly polarized fundamental pulse, planar molecular alignment can be naturally realized along the elliptical polarization plane of the second-harmonic pulse, resulting in the three-dimensional molecular orientation. Compared to another all-optical method to achieve three-dimensional molecular orientation, in which linearly polarized two-color laser fields with their polarizations crossed obliquely are employed, it is numerically demonstrated that our method with an elliptically polarized second-harmonic pulse is especially advantageous when the molecular orientation dynamics is nonadiabatic.