Alignment of neutral molecules by a strong nonresonant linearly polarized laser field

We demonstrate that a strong nonresonant nanosecond laser pulse can be used to align neutral molecules. Our technique, applicable to nonpolar as well as polar molecules, relies on the anisotropic interaction between the strong laser field and the induced dipole moment of the molecules. The degree of alignment is enhanced by increasing the laser intensity or by lowering the initial rotational temperature of the molecules. We measure the alignment by detecting the instantaneous direction of the photodissociated fragments with ion imaging techniques. We have also investigated the possibility of molecular orientation using an asymmetric potential created by the superposition of strong, nonresonant, two-color (ω+2ω) laser fields. The time-independent Schrodinger equations are numerically solved in an adiabatic regime. Our results suggest that our approach can be used to orient polar molecules if they are rotationally cold.