Studies On Induced Transparency And Related Phenomena In Hybrid Cavity Optomechanical Systems

Cavity optomechanical system mainly studies the interaction between electromagnetic radiation and nano-(or micro-)mechanical motion.Recently,cavity optomechanics is developing rapidly for its extensive application.Firstly,by using light,cavity quantum optomechanics promises to manipulate and detect mechanical motion in the quantum regime,which can create nonclassical states of light and mechanical motion.Secondly,cavity quantum optomechanics can detect small force,displacement,mass and other parameters with high optical sensitivity.Thirdly,in the cavity optomechanical system,motion of the mechanical resonator can be used as a universal transducer in order to modulate long-range interactions between stationary quantum systems.Fourthly,in the cavity optomechanical system,one can achieve optomechanically induced transparency and slow light,which provides the possibility for the final realization of a solid-state implementation of quantum memory.Fifthly,in the quantum information processing,different physical systems have different advantages,including good computation,long-time storage and long-distance communication.By using the interaction between the mechanical resonator and the optical cavity,different quantum systems can be combined in the hybrid optomechanical system.In this thesis,induced transparency and other physical phenomena in the hybrid optomechanical system are studied.Our results have great effect on discussing the characteristics of induced transparency,induced amplification,induced absorption,slow light and normal-mode splitting in the hybrid cavity optomechanical system which will be helpful to further study on squeezing,entanglement,precision measurement and other related problems in the hybrid optomechanical system.Firstly,we can study optomechanically induced transparency and slow light in the hybrid optomechanical system with a degenerate optical parametric amplifier.The system consists of the degenerate optical parametric amplifier,two charged mechanical resonators and an optical cavity.The coupling interaction between the cavity and a charged mechanical resonator is expressed by the radiation pressure term.There is no interaction between the cavity and the other charged mechanical resonator while there is Coulomb interaction between the two charged mechanical resonators.In such a nonlinear hybrid optomechanical system,we consider optomechanically induced transparency and the slow light by changing the Coulomb coupling strength,amplitude of the optical parametric amplifier,phase of the optical field driving the optical parametric amplifier,and power of the pump field.Due to the Coulomb interaction between the two charged mechanical resonators,two transparency window dips can occur which can be explained by using the mechanical dressed modes.We find that the Coulomb coupling strength has a significant impact on spacing between the two transparency window dips due to the mechanical dressed modes.Specifical y,with the increase of the Coulomb coupling strength,spacing between the two transparency window dips becomes wider.Moreover,one may achieve the long-lived slow light(i.e.,the group delay is about several milliseconds)and a switching from the superluminal to subluminal propagation via adjusting controlling parameters of the system.Secondly,we theoretically consider novel multiple transparency in a multimode quadratic coupling optomechanical system assisted with N cold ?-type three-level atoms.Specifically,coupling interaction between the two mechanical membranes and the cavity is quadratic.The optical cavity is driven by a strong coupling field and a weak probe field.The three-level atoms interact with an external controlling field and an internal cavity field.In the resolved sideband regime,there are four transparency windows dips resulted from atomic coherence and quadratic coupling in the absorption spectrum by using suitable parameters.The coupling interaction between three-level atom and the optical cavity(controlling)field generates the most left and right transparency window dips,while fluctuation of the mechanical membrane in displacement generates two middle transparency window dips.Next,we study how to switch the number of transparency window dips between two,three and four transparency window dips,and adjust spacing between two transparency window dips by changing the controlling parameters.Further,we also demonstrate normal-mode splitting in the hybrid cavity optical system,where the collective coupling strength can affect the splitting width of the output field.Thirdly,we analyze optomechanically induced transparency,optomechanically induced amplification and optomechanically induced absorption in the hybrid optomechanical system with an intrinsic two-level qubit.The hybrid optomechanical system consists of an optical cavity,a mechanical resonator and a two-level qubit.The coupling interaction between the two-level qubit(the cavity field)and the mechanical resonator is described by the Jaynes-Cummings(radiation-pressure)Hamiltonian,while there is no direct coupling between the two-level qubit and the cavity filed.In the resolved sideband regime,when only a probe field is applied to the left side of the cavity,double optomechanically induced transparency window dips can occur.In addition,spacing between the two transparency window dips is determined by the coupling strength between the two-level qubit and the mechanical resonator.If we consider effect of an auxiliary driving field on the mechanical resonator,optomechanically induced amplification can occur.Further,with the increase of amplitude of the auxiliary driving field,amplification amplitudes of the two transparency windows dips symmetrically become much deeper.Moreover,when the two weak probe fields are applied to the left and right sides of the cavity,under appropriate parameters,we can obtain the three channels for optomechanically induced absorption in the hybrid optomechanical system.Next,we discuss the problem on the path of the energy dissipation.In the three channels,the summation of mechanical excitations of the mechanical resonator and excitations of the two-level defect is always double of the normalized intra-cavity probe photon number for different values of the effective radiation pressure coupling.Finally,we also find that phase of the auxiliary driving field has a significant effect on the number and locations of channels for optomechanically induced absorption.