Study On Coherence Of Atomic-Assisted Hybrid Optomechanical System

In recent years,with the continuous development of nano precision manufacturing technology,the experimental devices in the optomechanical coupling system have been greatly improved on the micro scale.The improvement of experimental conditions also makes it possible for many quantum phenomena that were once inaccessible through the optomechanical coupling system.Optomechanics has entered a stage of rapid development.More and more scientists are interested in various novel optical quantum effects in the optomechanical system,so a variety of optomechanical systems have been developed,such as the atomic-assisted hybrid optomechanical system,the multi-mode optomechanical system and so on.Through these new cavity optomechanical systems,people have more and more in-depth research on various quantum effects in optomechanical systems,such as optomechanically induced transparency and optomechanical multistability.In this thesis,we mainly take the atomic-assisted hybrid optomechanical system as the research object,study the perfect optomechanically induced transparency and the optomechanical multistability in atomic-assisted optomechanical systems.Firstly,we take the two-level atomic-assisted optomechanical system as the research object,study the relevant conditions of achieving the perfect optomechanically induced transparency,and analyze the importance of the non-rotating wave approximation(NRWA)to achieve perfect optomechanically induced transparency on this basis.In the previous work,it was difficult to achieve the perfect optomechanically induced transparency in cavity optomechanical systems,because the influence of non-rotating wave approximation was often ignored.If we consider the NRWA effect,we can achieve the perfect optomechanically induced transparency,a deep and narrow transparency window can also be obtained to enhance the slow light effect,and greatly reduce the requirement of quality factor for achieving the perfect optomechanically induced transparency.In addition,this method is also applicable to other optomechanical systems,such as superconducting circuit systems,multimode optomechanical systems and rotating optomechanical systems.We believe that these results can be applied to the control of optical transmission in quantum information processing.Next,we study the optomechanical multistability.In the past,most of the relevant research work focused on the two-level atomic ensemble or Λ type three-level atomic ensemble.In this thesis,we take the three-level trapezoidal atomic-assisted optomechanical system as the research object.By using the method of numerical simulation,we analyze the optomechanical multistability in the three-level trapezoidal atomic-assisted optomechanical system.It is found that with the change of the inherent detuning between the optical cavity field and the atom,the solution of the steady-state position of the quantum resonator also has different situations.There is an optomechanical multistability phenomenon in the system,and the effective detuning between the optical cavity field and the atom will produce a similar phenomenon with the change of the inherent detuning between the optical cavity field and the atom.At the same time,we also study the multistability of the imaginary part of the off diagonal density matrix element and the imaginary part of the polarizability.The above results can help to provide a more detailed understanding of the optomechanical multistability,and may provide guidance for the research and development of optical devices for quantum computing and quantum information processing,such as optical switches and optical bistable devices.