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.
@article{arxiv.2303.10925,
title = {Meter-scale strong coupling between magnons and photons},
author = {Jinwei Rao and C. Y. Wang and Bimu Yao and Z. J. Chen and K. X. Zhao and Wei Lu},
journal= {arXiv preprint arXiv:2303.10925},
year = {2023}
}