Tristability of cavity magnon polaritons

Abstract

We carry out a theoretical study of the nonlinear behavior of cavity magnon polaritons (CMPs) under strong microwave driving, with two kinds of nonlinearity being involved: either (i) the photon Kerr effect (PKE) and the magnon saturation effect (MSE) or (ii) the magnon Kerr effect (MKE) and the MSE. The effects arising in these two cases are similar for the lower polariton mode of CMPs but opposite for the upper polariton mode. In case (i), the dominant nonlinearity for the upper polariton mode of CMPs changes from the MSE to the PKE as the driving intensity increases, which can lead to two hysteresis loops in opposite directions and hence to tristability. In case (ii), however, the upper polariton mode exhibits only the usual bistability rather than tristability since the MKE is dominated by the MSE. In particular, there is no bistable behavior in the upper polariton mode when the two nonlinearities balance each other. The results of this study provide a possible basis for the practical manipulation and control of information via the double nonlinearities in a cavity-magnon system.