Nanoscale transient polarization gratings

TL;DR

This paper demonstrates the creation of nanoscale transient polarization gratings using a free electron laser, revealing helicity-dependent magnetization dynamics by suppressing thermal effects, thus enabling new studies of chiral systems.

Contribution

The work introduces a novel method to generate nanoscale transient polarization gratings and compares its effects with intensity gratings, uncovering hidden helicity-dependent magnetic phenomena.

Findings

Suppressed thermal response in polarization gratings reveals helicity-dependent magnetization dynamics.

Demonstrated capability of FERMI free electron laser to produce nanoscale polarization gratings.

Potential application in studying chiral physical, chemical, and biological systems.

Abstract

We present the generation of transient polarization gratings at the nanoscale, achieved using a tailored accelerator configuration of the FERMI free electron laser. We demonstrate the capabilities of such a transient polarization grating by comparing its induced dynamics with the ones triggered by a more conventional intensity grating on a thin film ferrimagnetic alloy. While the signal of the intensity grating is dominated by the thermoelastic response of the system, such a contribution is suppressed in the case of the polarization grating. This exposes helicity-dependent magnetization dynamics that have so-far remained hidden under the large thermally driven response. We anticipate nanoscale transient polarization gratings to become useful for the study of any physical, chemical and biological systems possessing chiral symmetry.