Research On Photon Emission Features Of Quantum-dot-microcavity Coulping System

In recent years,quantum communication and quantum information processing has achieved fruitful research results in theory and experiments,which significantly improve the performance of information capacity,transmission efficiency,recognition accuracy and information security of information systems.Therefore,the communication research field,domestic and foreign government agencies and business pay more and more attention to quantum information technology.Quantum communication and quantum information processing has become the inevitable development direction of information photonics,which demands high-efficiency solid-state quantum light sources,and therefore how to achieve high-quality single-photon sources has become a hot research issue.The methods of generation a single-photon source include LED,LD decay,method using single radical or a single atom,a single molecule,material defects and a quantum dot.The single-photon source generated with a quantum dot,particularly with the system formed by quantum dots coupling with microcavities,has become the most potential single-photon source,because of its high oscillator strength,high quantum efficiency,narrow spectral width and other advantages.Cavity quantum electrodynamics is the study of the interaction between electromagnetic fields and matter in a confined space,and the quantum-dot-microcavity coupling system is an important model in this field.The photon emission features of the system are essentially the results of the interaction between quantum light field and matter,and for the characteristics of the quantum field need to be described by the statistical characteristics of the system,in which the second-order correlation function of the system is an important indicator evaluating the performance of a single-photon source.The systems of quantum dots coupling with microcavities in different structures will bring many new phenomenon.The interaction between quantum dots and different combination structures of microcavities will bring many new phenomenon,which is the focus of this paper.In this paper,we carry out our research on photon emission features of the quantum-dot-microcavity coupling system as follows:We start our work with learning the theory and calculation method of cavity quantum electrodynamics.Then we solve the master equations of several common quantum-dot-microcavity coupling systems with the quantum trajectory method,and with the results,we can study the statistical properties of the photons in these systems.On this basis,we propose a quantum-dot-ring-microcavities coupling system model.The system includes three single-mode microcavities and one of them coupling with single quantum dot.We use a continuous wave driving system in two ways,respectively,driving two empty cavities and driving a cavity coupled a quantum dot and an empty cavity at the same time.Under the condition of the same total driving strength,we adjust the driving strength ratio between two cavities to study the system and in both ways we can obtain the low second-order correlation and the sub-Poissonian feature of photons.Furthermore,we study the influence on the second-order correlation and number of the cavity photons by changing the system parameters,including total driving strength,coupling strength between quantum dot and coupling strength between cavities.With these conclusions,we optimize the single photon emission characteristics of the system and lower the second-order correlation to 10k-4,which means the system can be used to generate a pure single-photon source.Based on CQED,we propose a quantum-dot-ring-microcavities coupling system model in this paper to achieve a stable and high-efficiency single-photon source.Then we discuss the single photon emission characteristics in different system parameters and optimize the system to achieve strongly sub-Poissonian light generation.Through our work,we provide the theoretical guidance for the generation of single-photon source in laboratory.