Unveiling a Pump-Induced Magnon Mode via its Strong Interaction with Walker Modes

TL;DR

This paper reports the discovery of a pump-induced magnon mode in a ferrimagnet that exhibits strong coupling with Walker modes, enabling tunable anticrossings and a magnetic frequency comb for potential coherent information processing.

Contribution

It introduces a novel pump-induced magnon mode that couples with Walker modes, demonstrating tunable anticrossings and a magnetic frequency comb driven by nonlinear interactions.

Findings

Observation of power-dependent anticrossing of Walker modes

Generation of a pump-induced magnon mode with strong coupling

Realization of a magnetic frequency comb from nonlinear dynamics

Abstract

We observe a power-dependent anticrossing of Walker spin-wave modes under microwave pumping when a ferrimagnet is placed in a microwave waveguide that does not support any discrete photon mode. We interpret this unexpected anticrossing as the generation of a pump-induced magnon mode that couples strongly to the Walker modes of the ferrimagnet. This anticrossing inherits an excellent tunability from the pump, which allows us to control the anticrossing via the pump power, frequency, and waveform. Further, we realize a remarkable functionality of this anticrossing, namely, a microwave frequency comb, in terms of the nonlinear interaction that mixes the pump and probe frequencies. Such a frequency comb originates from the magnetic dynamics and thereby does not suffer from the charge noise. The unveiled hybrid magnonics driven away from its equilibrium enriches the utilization of anticrossing for coherent information processing.