Tunable quasi-discrete spectrum of spin waves excited by periodic laser patterns

TL;DR

This paper introduces a method for selectively exciting spin waves with tunable, quasi-discrete spectra using patterned femtosecond laser pulses, enabling precise control over wave properties for advanced magnonic applications.

Contribution

It demonstrates a novel approach for controlling spin wave excitation via spatially patterned laser pulses, allowing tunable spectral and propagation characteristics.

Findings

Multiple wavepackets with different velocities are generated.

Spectral peak frequencies are controllable by laser impact polarity and period.

The method enables comprehensive optical control of spin wave parameters.

Abstract

We present a concept for selective excitation of magnetostatic surface waves with quasi-discrete spectrum using spatially patterned femtosecond laser pulses inducing either ultrafast change of magnetic anisotropy or inverse Faraday effect. We micromagnetically simulate excitation of the waves with periodically patterned uni- or bipolar laser impact. Such excitation yields multiple wavepackets propagating with different group velocities, whose dispersion corresponds to the set of quasi-discrete points. In addition, we show that the frequency of the spectral peaks can be controlled by the polarity of the periodic impact and its spatial period. Presented consideration of multiple spatially periodic magnetostatic surface wave sources as a whole enables implementation of a comprehensive toolkit of spatio-temporal optical methods for tunable excitation and control of spin wave parameters