Controlling the sense of molecular rotation

TL;DR

This paper presents a novel laser pulse scheme to control the direction of molecular rotation, creating permanent anisotropy in molecular gases and enabling selective manipulation of molecular components.

Contribution

A new method using polarization and timing of ultrashort laser pulses to induce unidirectional, field-free molecular rotation with potential applications in controlling molecular interactions.

Findings

Achieved unidirectional molecular rotation with laser pulses.

Molecular rotation confined to a plane defined by pulse polarizations.

Potential for selective control in molecular mixtures.

Abstract

We introduce a new scheme for controlling the sense of molecular rotation. By varying the polarization and the delay between two ultrashort laser pulses, we induce unidirectional molecular rotation, thereby forcing the molecules to rotate clockwise/counterclockwise under field-free conditions. We show that unidirectionally rotating molecules are confined to the plane defined by the two polarization vectors of the pulses, which leads to a permanent anisotropy in the molecular angular distribution. The latter may be useful for controlling collisional cross-sections and optical and kinetic processes in molecular gases. We discuss the application of this control scheme to individual components within a molecular mixture in a selective manner.