Shaping Spin Behavior: Interfering Light Alter Magnetization Dynamics

What is it about?

Optical manipulation of spins holds promise for future data processing and storage devices. In our study, we investigated a novel method to influence magnetization behavior. Unlike most previous approaches that relied on a single ultrashort pulse, we used two noncollinear ultrashort optical pulses that simultaneously initiated magnetization precession in a permalloy thin film. The observed magnetization dynamics exhibited a significant deviation when compared to single-pulse excitation.

Featured Image

Photo by israel palacio on Unsplash

Photo by israel palacio on Unsplash

Why is it important?

The observed disparities in magnetization dynamics between single and dual optical excitation challenge our current understanding of the interplay between light and magnetic materials. At the present moment, it remains unclear what precisely alters within the material under the influence of two ultrashort pulses in interference. Particularly surprising is the timescale of the difference in magnetization dynamics, spanning over the nanosecond timescale – four orders of magnitude longer than the duration of the excitation pulses. This intriguing observation may suggest that interfering light may possess previously unrecognized properties capable of temporarily modifying electron behavior. While currently speculative, if confirmed, this could signify a paradigm shift in physics, challenging the assumption of equal electron behavior across our universe. Consequently, further investigations are imperative to unravel the underlying physics of the interaction between matter and interfering light.