Steering between level repulsion and attraction: broad tunability of two-port driven cavity magnon-polaritons

Abstract

Cavity-magnon polaritons (CMPs) are the associated quasiparticles of the hybridization between cavity photons and magnons in a magnetic sample placed in a microwave resonator. In the strong coupling regime, where the macroscopic coupling strength exceeds the individual dissipation, there is a coherent exchange of information. This renders CMPs as promising candidates for future applications such as in information processing. Recent advances on the study of the CMP now allow not only for creation of CMPs on demand, but also for tuning of the coupling strength—this can be thought of as the enhancement or suppression of information exchange. Here, we go beyond standard single-port driven CMPs and employ a two-port driven CMP. We control the coupling strength by the relative phase ϕ and amplitude field ratio δ _0 between both ports. Specifically, we derive a new expression from input–output theory for the study of the two-port driven CMP and discuss the implications on the coupling strength. Furthermore, we examine intermediate cases where the relative phase is tuned between its maximal and minimal value and, in particular, the high δ _0 regime, which has not been yet explored.

Keywords

• microwave cavity resonators
• cavity-magnon-polaritons (CMPs)
• ferromagnetic resonance
• hybrid systems
• strong coupling