Orientation and Alignment Dynamics of Polar Molecule Driven by Shaped Laser Pulses

Abstract

We review on the theoretical status of intense laser orientation and alignment. The evolution of the rotational wave packet and its dynamics leading to orientation and alignment is the topic of the present discussion. The major part of the article basically presents an overview on recent theoretical progress in controlling the orientation and alignment dynamics of a molecule by means of shaped laser pulses. The various theoretical approaches that lead to orientation and alignment ranging from static electrostatic field in combination with laser field(s), combination of orienting and aligning field, combination of aligning fields, combination of orienting fields, application of train of pulses etc. are discussed. The orientation and alignment both can occur in adiabatic and non-adiabatic conditions with the rotational period of the molecule into consideration. The discussion is mostly limited to non-adiabatic rotational excitation (NAREX). A particular focus is put on the so called half-cycle pulse (HCP) and square pulse (SQP). The effect of ramped pulses is also under focus. The effect of collision on the various laser parameters is also given concern. We summarize the current discussion by presenting a consistent theoretical approach for describing the action of such pulses on movement of molecules. The impact of a particular pulse shapes on the post-pulse dynamics is calculated and analysed. The concept of alignment is extended from one-dimensional alignment to three-dimensional alignment with the proper choice of molecule and the polarised light. We conclude the article by discussing the potential applications of intense laser orientation and alignment.