Spin-wave amplification techniques are key to the realization of magnon-based computing concepts. We introduce a novel mechanism to amplify spin waves in magnonic nanostructures. Using the technique of rapid cooling, we create a non-equilibrium state in excess of high-energy magnons and demonstrate the stimulated amplification of an externally seeded, propagating spin wave. Using an extended kinetic model, we qualitatively show that the amplification is mediated by an effective energy flux of high energy magnons into the low energy propagating mode, driven by a non-equilibrium magnon distribution.
@article{arxiv.2208.11455,
title = {Stimulated amplification of propagating spin waves},
author = {David Breitbach and Michael Schneider and Björn Heinz and Felix Kohl and Jan Maskill and Laura Scheuer and Rostyslav O. Serha and Thomas Brächer and Bert Lägel and Carsten Dubs and Vasil S. Tiberkevich and Andrei N. Slavin and Alexander A. Serga and Burkard Hillebrands and Andrii V. Chumak and Philipp Pirro},
journal= {arXiv preprint arXiv:2208.11455},
year = {2023}
}