Creating rotational coherences in molecules aligned along the intermediate moment of inertia axis

TL;DR

This paper introduces a computational method using tailored optical centrifuge pulses to create and control rotational coherences in asymmetric top molecules, enabling precise 3D molecular alignment along specific axes for advanced imaging applications.

Contribution

It presents a novel coherent control scheme employing shaped optical centrifuge pulses to generate specific rotational coherences in molecules, particularly aligning the intermediate inertia axis along the laser propagation direction.

Findings

Successfully demonstrated rotational state preparation in D2S molecules.

Achieved stable alignment of the molecular intermediate inertia axis.

Enhanced potential for photo-electron imaging experiments.

Abstract

We propose and computationally study a method for simultaneously orienting the angular momentum of asymmetric top molecules along: 1) a laboratory-fixed direction; 2) the molecular intermediate moment of inertia axis; 3) the laser field wavevector. For this purpose we utilize a coherent control scheme in which a tailored-pulse optical centrifuge populates rotational states with well defined projections of the total angular momentum onto molecular axes. Appropriately time-shaped optical centrifuge pulses can leave the rotational wavepacket in peculiar rotational coherences which lead to a good degree of 3-dimensional transient alignment, with an arbitrary molecular axis pointing along the laser pulse propagation direction. As an example, we demonstrate how to generate highly resilient rotational quantum states of D2S in which the molecule rotates mainly about its intermediate inertia axis, such that its electric dipole moment is permanently aligned along the propagation direction of the laser pulse. Applications might include accessing less obscured information in various photo-electron imaging experiments.