Dissipation-induced nonreciprocal second-order sideband generation in cavity magnonics

Dissipative coupling generally results in complex effective spin–photon interactions, which have significant applications in nonreciprocal transport and enhanced sensing technologies. In this paper, we consider the cooperative effect of coherent and dissipative magnon–photon couplings in an open cavity magnonical system. By enhancing the magnon Kerr nonlinearity with an additional microwave driving field, magnon-induced nonlinear phenomena such as bistability and second-order sideband generation (SSG) can be obtained. By continuously adjusting the ratio of dissipative to coherent coupling strengths, nonreciprocal SSG is observed near the zero-damping condition. Furthermore, the results show that the isolation ratio (the efficiency of the nonreciprocal SSG) can reach up to 82 dB. In addition, increasing the power of the microwave driving field broadens the control range of the dissipative coupling strength, within which the isolation ratio remains above 10 dB. These findings have potential implications for high-precision measurement and on-chip manipulation of light propagation.