Controlling molecular angular momentum orientation by Raman pumping and optical ac Stark effect

The anisotropic interaction of an external electric field with the polarizability of a molecule is investigated for intense optical fields. The ac Stark effect yields an energetic splitting of normally degenerate |J, mJ〉 states. Combined with stimulated Raman pumping the effect can be exploited to prepare spatially oriented and vibrationally excited molecules by tuning the Stokes laser frequency to excite single |J, mJ〉 states. The effect can also be used to directly measure |mJ〉 quantum state distributions, either via Raman probing or in combination with other photoexcitation techniques.