Molecular alignment stimulated by the coupled pulses of the ultrashort laser pulse and the terahertz pulse

Field-free molecular alignment can be induced by the strong ultrashort laser pulses. Here, the improvement of the alignment is completed by the coupled pulses of the ultrashort laser pulse and the strong broadband terahertz pulse. The gaseous CO molecules are aligned by such coupled pulses, and the evolution of its states are studied based on the rigid rotor approximation theory with the simulation method. The influences of the pulses parameters on the alignment are also discussed.