Theoretical Study On The Emission,state Transfer Of Solid-state Single Quantum Systems And Photon Transport In Integrated Photonic Circuits

Quantum information technologies are promising solutions for solving the bottlenecks of traditional information technologies in information capacity,processing speed,security,etc.,and therefore have received extensive attention from academia and industry around the world.Over the past four decades,scientists have proposed and developed a variety of physical platforms for realizing quantum information processing technologies.Among others integrated photonic platform is a candidate with extraordinary potential.The platform boasts the integration,functional scalability,and stability required by large-scale photonic quantum information processing,which has further advantages of being robust against decoherence,potentially high-speed,and broadband.In order to realize large-scale quantum information processing on integrated photonic chips,we need bybrid integration of solid-state single quantum systems(such as quantum dots,color centers in diamond,organic single molecules,etc.)and various photonic units(including waveguides,cavities,beam splitters,polarization controller,etc.)on one chip.Hybrid integration not only brings challenges in engineering and implementation,but also poses new theoretical problems,including how to achieve near-unity coupling efficiency between solid-state single quantum systems and planar waveguide devices,how to realize quantum information transfer between static qubits,how to analyze photon transport in hybrid integrated photonic circuits,how to achieve nonlinear interactions between indistinguishable photons,etc.Dedicated to the above problems and challenges and based on waveguide quantum electrodynamics,this thesis conducts a series of theoretical researches on the emission,state transfer of solid-state single quantum systems and photon transport in integrated photonic circuits,including:1.Theoretical description and efficient numerical implementation are provided for calculating the coupling among quantum emitters,micro-ring resonators,and waveguides.We leverage the special coupling features of quantum emitters and ring waveguide,and propose a semi-analytical method for calculating the coupling between quantum emitters and micro-ring resonators.This method circumvents 3D full-wave simulations of the whole micro-ring resonator with high quality factor,and requires much less memory and computation time.2.We propose a method to characterize the 3D structure and orientation of a colloidal quantum dot’s emission dipole using Purcell effect.This near-field scheme is based on the change of the spontaneous decay rate of the quantum dot.In comparison with methods based on far-field imaging,our method is immune to the effects of optical setup and detection scheme.The characterization results are more intuitive and show high sensitivity.3.A scheme to synthesize time reversal symmetric wave packets based on cavity network is proposed.For a composite system composed of a two-level system and cavity network,the emitted single photon pulse shape is determined by the eigenstates of the composite system.Using the simplest chain cavity network for wave packet synthesis,and by using only three resonators,the composite system can emit a single-photon wave packet into the waveguide with a symmetry factor greater than99%.4.We contruct a composite quantum node based on the two-level system-cavity chain structure to realize perfect quantum state transfer between two nodes.The specific protocols for transferring the excited state and superposition states are exemplified.We suggest the experimentally feasible design of the composite quantum node based on Si N waveguide micro-ring resonator and Ge V color center.The influence of nonideal conditions on the performance is discussed.5.We study the two-photon transport in planar integrated photonic circuits,and characterize the nonlinear interactions mediated by single-quantum systems.We develop methods to quantitatively characterize the changes of pulse shape,phase and entanglement during the transport.A scheme is proposed to realize the time-reversal transformation for specific single-and two-photon pulses.Thereby the change of entanglement during the transport can be suppressed and a controlled π phase quantum logic gate can be expected.