Molecular alignment using circularly polarized laser pulses

TL;DR

This paper demonstrates that circularly polarized femtosecond laser pulses can induce field-free molecular alignment in linear and planar molecules, enabling new control methods for molecular imaging.

Contribution

It introduces a novel approach using circular polarization to achieve and control molecular alignment outside the polarization plane.

Findings

Circular polarization aligns benzene's molecular plane to the polarization plane.

Circular polarization aligns O$_2$ along the laser propagation axis at specific phases.

The method enables control of molecular orientation for imaging applications.

Abstract

We show that circularly polarized femtosecond laser pulses produce field-free alignment in linear and planar molecules. We study the rotational wavepacket evolution of O$_2$ and benzene created by circularly polarized light. For benzene, we align the molecular plane to the plane of polarization. For O$_2$, we demonstrate that circular polarization yields a net alignment along the laser propagation axis at certain phases of the evolution. Circular polarization gives us the ability to control alignment of linear molecules outside the plane of polarization, providing new capabilities for molecular imaging.