Meter-scale strong coupling between magnons and photons

TL;DR

This paper demonstrates a meter-scale strong coupling between magnons and photons at room temperature using an active microwave cavity with gain, enabling long-range control and potential applications in information networks.

Contribution

The authors experimentally realize long-distance strong photon-magnon coupling at room temperature by integrating gain into a microwave cavity, a novel approach in cavity magnonics.

Findings

Achieved 20 m coherent coupling and 7.6 m dissipative coupling.

Enabled remote control of coupling via traveling wave modulation.

Proposed a general method for long-range coupling in physical systems.

Abstract

We experimentally realize a meter-scale strong coupling effect between magnons and photons at room temperature, with a coherent coupling of 20 m and a dissipative coupling of 7.6 m. To this end, we integrate a saturable gain into a microwave cavity and then couple this active cavity to a magnon mode via a long coaxial cable. The gain compensates for the cavity dissipation, but preserves the cavity radiation that mediates the indirect photon-magnon coupling. It thus enables the long-range strong photon-magnon coupling. With full access to traveling waves, we demonstrate a remote control of photon-magnon coupling by modulating the phase and amplitude of traveling waves, rather than reconfiguring subsystems themselves. Our method for realizing long-range strong coupling in cavity magnonics provides a general idea for other physical systems. Our experimental achievements may promote the construction of information networks based on cavity magnonics.