Level Attraction Due to Dissipative Magnon-Photon Coupling

TL;DR

This paper demonstrates dissipative magnon-photon coupling via the cavity Lenz effect, revealing level attraction phenomena and offering new control methods for light-matter interactions in hybrid systems.

Contribution

It introduces the experimental observation of dissipative magnon-photon coupling and a method to control the interplay between coherent and dissipative effects.

Findings

Observation of level attraction with mode coalescence

Development of a control method for coupling effects

Identification of a cancellation condition between effects

Abstract

We report dissipative magnon-photon coupling caused by cavity Lenz effect, where the magnons in a magnet induce a rf current in the cavity, leading to a cavity back action that impedes the magnetization dynamics. This effect is revealed in our experiment as level attraction with a coalescence of hybridized magnon-photon modes, which is distinctly different from level repulsion with mode anticrossing caused by coherent magnon-photon coupling. We develop a method to control the in- terpolation of coherent and dissipative magnon-photon coupling, and observe a matching condition where the two effects cancel. Our work sheds light on the so-far hidden side of magnon-photon coupling, opening a new avenue for controlling and utilizing light-matter interactions.