Single-shot imaging of ultrafast all-optical magnetization dynamics with a spatio-temporal resolution

TL;DR

This paper introduces a high-sensitivity, single-shot magneto-optical imaging system capable of visualizing ultrafast all-optical magnetization dynamics with high spatio-temporal resolution, demonstrated on YIG:Co films.

Contribution

The authors developed a flexible, resonant two-color pump-probe imaging system for real-time visualization of ultrafast magnetization changes.

Findings

Successfully visualized all-optical switching in YIG:Co films.

Mapped the spatial-temporal distribution of photo-induced anisotropy.

Tracked laser-induced magnetization precession in real-time.

Abstract

We present a laboratory system for single-shot magneto-optical (MO) imaging of ultrafast magnetization dynamics with high-sensitivity of MO rotation. We create a stack of MO images repeatedly employing a single pair of a pump and defocused probe pulses to induce and visualize MO changes in the sample. Both laser beams are independently wavelength-tunable allowing for a flexible, resonant adjustable two-color pump and probe scheme. To increase the MO contrast the probe beam is spatially filtered. We performed the all-optical switching experiment in Co-doped yttrium iron garnet films (YIG:Co) to demonstrate the capability of the presented method. We determine the spatial-temporal distribution of the effective field of photo-induced anisotropy driving the all-optical switching of the magnetization in YIG:Co film without an external magnetic field. Moreover, using this imaging method, we tracked the process of the laser-induced magnetization precession.