Synchronized spin-photon coupling in a microwave cavity

Abstract

We study spin-photon coupling in a cavity in the presence of a relative phase shift between two ferromagnetic resonance driving forces. We show that the anticrossing gap can be manipulated by varying the relative phase. Increasing the phase difference leads to narrowing the anticrossing gap between two hybridized modes and eventually phase-locked coupling when the relative phase equals $\ensuremath{\pi}$. The ferromagnetic resonance (FMR) and cavity modes become phase locked and oscillate at the same frequency near the resonance frequency. The characteristic FMR linewidth drop and transmission amplitude enhancement are demonstrated. The phase-resolved spin-photon coupling can be used both for phase imaging and for controlling coupling parameters.