Mixed-field orientation of molecules without rotational symmetry

TL;DR

This paper explores how asymmetric molecules can be oriented in three dimensions using combined laser and electric fields, revealing new methods for controlling molecular orientation.

Contribution

It demonstrates experimentally and theoretically that mixed-field orientation can achieve 3D control of asymmetric molecules without rotational symmetry, using specific field configurations.

Findings

Elliptically polarized laser fields induce complete 3D orientation.

Linearly polarized laser fields produce 1D orientation along the most polarizable axis.

Combining a linearly polarized laser with a strong dc electric field enables 3D orientation.

Abstract

The mixed-field orientation of an asymmetric-rotor molecule with its permanent dipole moment non-parallel to the principal axes of polarizability is investigated experimentally and theoretically. We find that for the typical case of a strong, nonresonant laser field and a weak static electric field complete 3D orientation is induced if the laser field is elliptically polarized and if its major and minor polarization axes are not parallel to the static field. For a linearly polarized laser field solely the dipole moment component along the most polarizable axis of the molecule is relevant resulting in 1D orientation even when the laser polarization and the static field are non parallel. Simulations show that the dipole moment component perpendicular to the most-polarizable axis becomes relevant in a strong dc electric field combined with the laser field. This offers an alternative approach to 3D orientation by combining a linearly-polarized laser field and a strong dc electric field arranged at an angle equal to the angle between the most polarizable axis of the molecule and its permanent dipole moment.