Magnon-Induced Dynamics Of Nonlinearity And Its Application In Whispering-Gallery Mode Optomagnonics

With the development of information processing and transmission,there is a growing demand for multitask processing systems with strong coupling and low loss.Multitask processing systems are designed to ensure the reliable storage,processing and transmission of information.Therefore,some highly adjustable hybrid systems have emerged,such as cavity quantum electrodynamics,cavity optomechanics,cavity magnomechanics and cavity optomagnonics.These hybrid systems can combine the different physical components and their complementary functions to realize multitask processing.Magnons have great advantages in information processing,such as low loss,long life-time and large spin density which is conducive to the realization of strong coupling in hybrid systems.Moreover,the frequency of the magnon can be adjusted in a wide range,and it is regarded as an excellent information carrier.In addition,the precession frequency of magnon mode is adjusted by the degree of freedom of external magnetic field,so it is beneficial for the controllable nonlinear devices.Cavity optomagnonics combines the advantages of optical mode and magnon mode,providing a reliable platform for quantum storage,quantum communication.In this dissertation,different nonlinear hybrid systems are constructed using the whispering-gallery mode cavity optomagnonical system,and the nonlinear dynamic evolution of low threshold controllable high-order sideband and chaos is studied.Moreover,the magnetic sensing application is also studied based on the optomagnonical nonlinear coupling.The main works are divided into three parts:1.The generation of high-order sideband is investigated in the hybrid atom-optomagnonical system and the optomagnonical system coupled with two nanotips.First,the optomagnonics is combined with two-level atom to form a hybrid coupling system,in which the change of nonlinear intensity of light field is explored and the effective control of the optical high-order sideband by magnon mode is realized.The generation of the low-threshold sideband spectrum in hybrid atom-cavity optomagnonical system is achievied.Secondly,in order to further study the response modulation of high-order sideband amplitude and order,a coupling system of two nanoscatterers and the optomagnonics is constructed.Based on the periodic exceptional points induced by nanotips,the optical high-order sidebands of the system are studied.It is found that typical nonperturbative spectral characteristics and low threshold optical sidebands can be observed when appropriate parameters are selected.In addition,because the precession frequency of the magnon mode is affected by the applied bias magnetic field,it reminds us a new controllable degree of freedom in the regulation of sideband properties.2.The theory of parity-time symmetry is introduced into the optomagnonical system.Based on the coupling system,the characteristics of parity-time symmetry and breaking are analyzed and investigated.The generation and regulation of low-threshold chaos are explored.It is found that the chaotic evolution in the cavity can be controlled by adjusting the external bias magnetic field.In addition,the magnitude of the tunneling coupling strength also has a significant impact on the chaotic threshold.Finally,comparing the dependence of Lyapunov exponent on driving amplitude between the traditional passive-passive and the proposed active-passive coupling optical molecular structures,it is shown that the active-passive scheme can achieve low-threshold chaos(nW).3.A magnetometer with ?T resolution based on the nonlinear theory of the whispering-gallery mode optomagnonics coupled system is designed.The key of detecting the external magnetic field with the proposed magnetometer is to measure the frequency shift.Given the gyromagnetic ratio of the material,and according to the linear relationship between the frequency shift and the external magnetic field,the applied magnetic field can be read.The advantage of the magnetic sensing system is that it does not need additional mechanical degrees of freedom,and can read the magnetic field directly through the optomagnonics,which expands the detecting ranges of the magnetic field and makes the measurement more stable.