Studies On Quantum And Nonlinear Properties Of Cavity Optomechanics Systems

In recent years,the cavity optomechanics system formed by the combination of mechanical oscillator and optical cavity field has become an ideal platform for people to observe macroscopic quantum phenomena and test quantum theory.Therefore,the cavity optomechanics system has attracted wide attention both theoretically and experimentally.In this paper,we have studied the entanglement characteristics of the atom-mixing optomechanical cavity,studied the double optomechanically induced transparency and amplification of the hybrid optical parametric amplifier in a optomechanical cavity,and studied the dark state of the optical cavity.In Chapter three,we study the entanglement properties of three subsystems(atomic ensemble and optical cavity field,atomic ensemble and movable mirror,movable mirror and optical cavity field)in a hybrid optomechanical cavity consisting of optical cavity field,movable mirror,charged body and atomic ensemble.Starting with the Hamiltonian of the optomechanical cavity,the entanglement characteristics of the optomechanical cavity are obtained by Heisenberg-Langevin equation and the entanglement logarithmic negativity formula.The numerical results show that multi-body entanglement occurs in the hybrid cavity optomechanics system.The power of driving field,Coulomb interaction force and atomic ensemble coupling strength all affect the entanglement characteristics of the three subsystems.As we expected,by introducing Coulomb interaction force,the influence of optomechanical cavity on environmental temperature can be improved.In Chapter four,We mainly study tunable characteristics of double optomechanically induced transparency and amplification in a hybrid optomechanical system consisting of an optical parametric amplifier.We study the dynamics of the hybrid optomechanical system under the resolved sideband regime and red detuning.The transmission of the probe field is obtained by solving the Heinsenberg-langevin equation and the standard input and output.The effects of optical parametric amplifieron the phenomena of optomechanically induced transparency and amplification are analyzed.In Chapter five,we study the steady-state photon number distribution of each optical cavity field in a chain-coupled and non-chain-coupled system consisting of N single-mode optical cavity fields.We find that it is viable to realize a single or multiple dark mode.Such dark modes arise from perfect destructive interference between different coupling pathways and are in analogy to atomic dark states in the(43)or tripod systems.In a chain-coupled,it is of more interest that a sharp dark-mode dip may be attained in the three-cavity system and two dark modes may be attained in the four-cavity system,and so on.In non-chain-coupled,a sharp dark-mode dip may be attained in the four-cavity system and two dark modes may be attained in the five-cavity system,and so on.The flexible tunability of such dips and peaks is beneficial to design sensitive photonic devices of switching or measuring.