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

We propose a novel 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.