Field-free molecular alignment induced by a super-Gaussian laser pulse

Abstract

In this paper, the field-free molecular alignment induced by a super-Gaussian laser pulse is studied by a quantum mechanical calculation. It is shown that the super-Gaussian pulse has an advantage over the standard Gaussian pulse in enhancing the maximal degree of field-free alignment at constant pulse energy in an impulsive regime. Furthermore, the maximal degree of the molecular alignment during the laser pulse depends on the laser intensity and the pulse duration, and that after the laser pulse is related to all the parameters including the intensity, duration, and shape of the laser pulse, as well as the molecular property in intermediate regimes. The oscillation frequency of the molecular alignment during the laser pulse is proportional to the amplitude of the laser pulse at the same duration. Additionally, for the post-pulse alignment, a specific laser intensity and a proper pulse energy can improve the molecular alignment and the large shape parameter N can be beneficial for enhancing the molecular alignment to some extent.