Coherent Perfect Absorption In The Nonlinear Regime Of Cavity Magnonics System

Quantum systems for computation,communication and sensing have blossomed in the past decade.Thanks to the establishment of hybrid quantum systems,the systems composed of different subsystems with complementary advantages have become the most promising plat-form for the development of quantum technologies.The cavity-magnonics system has aroused considerable interest.The cavity-magnonics system consists by magnons in the yttrium iron garnet(YIG)and microwave photons.Owing to the Heisenberg spin-exchange interaction,the spin ensemble in the YIG material has a low damping rate,and due to the high spin density,it is easy to realize the strong-coupling regime between the magnons and the cavity photons.In both fundamental study and practical applications,the control of photons is an impor-tant research topic.In this thesis,we focus on the coherent perfect absorption in the cavity-magnonics system.Theoretically,we derive the coherent-perfect-absorption conditions for the cavity-magnonics system,and have experimentally shown the effect of the Kerr nonlinearity.In both linear and nonlinear regimes,the influence of system parameters on the coherent-perfect-absorption conditions is studied.The bistability caused by the Kerr effect is observed in the nonlinear regime,and it is shown that near-coherent perfect absorption can be achieved in a large range of the driving power.