The Study Of Nonlinear Effect In Cavity Optomechanical&Magnonic Systems And Its Application

Cavity optomechanics using high-quality optical microcavities to enhance the interaction between light fields and mechanical oscillators,has become an important cutting-edge research in quantum optics,nonlinear optics,precision measurement and quantum information.The optomechanical interaction mediated by the radiationpressure force belongs to the nonlinear feedback coupling,which manifests extremely rich nonlinear effects and quantum characteristics.The studies about the optomechanical nonlinear effects and its application can deepen our understanding of the mechanical effect of light,and has a wide application prospect in gravitational wave detection,ground state cooling of mechanical oscillator,quantum information processing,and even in fundamental tests of quantum mechanics.Cavity magnonics is an emerging field that studies the coherent coupling between cavity photons and collective spin excitations(magnons)by magnetic dipole-dipole interaction.Magnon is expected to replace charge as an information carrier in the post-Moore era,which can effectively avoid the severe heating caused by the high-speed charge movement and frequent collisions in the chip,thereby opening up a new way to achieve low-power and high-speed information storage and logic operation chips.In this thesis,we study the nonlinear effects and its application of the cavity optomechanical systems and cavity magnonic systems,including the following aspects:1.We propose a feasible scheme to realize the generation and amplification of high-order sideband in a cavity optomechanical system by using two-level atoms.The results show that the two-level atoms coupled in the cavity can modify the distribution of the optical field and effectively enhance the optomechanical nonlinearity.In addition,we study the intensity characteristics of high-order sideband,especially the spectral structure and non-perturbative features of the plateau region and cutoff region under different coupling parameter conditions.2.We propose a theoretical scheme for realizing magnetic-field-controlled slow light in a hybrid atom-cavity system.Under the external magnetic field,the strontium atoms undergo Zeeman splitting and induce transparent window in the transmission spectrum.We show that the dispersion of the transparent window can be modified to exhibit slow light,and the magnetic field can be seen as a ”switch” that triggers slow light.Our work effectively solves the generation and regulation of slow light,which has important practical significance in optical communication and optical storage.3.We analyze the nonlinear dynamics of whispering-gallery microresonators.The results show that by controlling the relative position of nanoparticles in the cavity field,the evolution of the system undergoes periodic oscillation,period-doubling bifurcation and until occurs chaos.We also show that the chaotic motion of the system is non-reciprocal near the exceptional point induced by the non-Hermitian mode coupling.We introduce the concept of chirality into the study of chaotic dynamics,and define a chirality parameter to describe the non-reciprocity of chaotic motion.4.We study the high-order sideband generation and magnon chaos induced by magnon Kerr nonlinearity in a cavity magnonic system.A feasible scheme for generating and regulating high-order sideband by adjusting the external magnetic field is proposed.We further find that the transition between the regular state and the chaotic state in magnon dynamic evolution can be achieved by changing the relative phase of the microwave driving field.The study of the magnon Kerr nonlinearity can deepens our understanding of the physical nature of collective spin excitations.5.Starting from the numerical solution of the quantum master equation,the quantum statistical features of the magnons characterized by the second-order correlation function are analyzed,and the bunching,anti-bunching and blockade effects of magnons are discussed in detail.We point out that the magnon blockade effect is caused by the strong interplay between the magnon and the qubit.We also find that the magnon blockade effect can be observed only in a low ambient temperature.As a pure quantum phenomenon,the study of blockade effect is a key step to explore the quantum properties of magnons,and also provides theoretical support for the realization of single magnon level quantum manipulation.In a word,this thesis is the summary of the study about the nonlinear effect in cavity optomechanical systems and cavity magnonic systems.These results not only deepen our understanding of optomechanical nonlinearity and magnon Kerr nonlinearity,but also profound enlightenment to the practical application of the cavity optomechanics and cavity magnonics in precision measurement,quantum simulation and optical information science.