Storage,Retrieval,and Splitting Of Linear And Nonlinear Optical Pulses Via Electromagnetically Induced Transparency

Since the invention of laser in the 1960 s,photons have become an ideal carrier of information processing technology.Photons have the advantages of fast propagation speed,the small interaction between photons,and the ability to carry much more infor-mation.Optical storage is one of the key technologies of optical information processing,while the classical optical storage technology,e.g.,compact disk technology,has been widely used.Quantum storage has attracted great attention due to the vital great appli-cation prospects in quantum technology fields,including quantum computing,quantum information,precision spectroscopy,and precision measurement.However,there still remains many challenges which pull far away from the needs of practical application.The key problems to be solved are to obtain a appropriate storage medium,build solid-state quantum storage devices,and improve the storage time,storage efficiency,and storage fidelity.Electromagnetically induced transparency(EIT)is one of the key technologies to study optical storage.It is a quantum interference effect which can make the medium transparent by controlling the strong laser field,so that the probe field can pass through the medium without being absorbed by the medium.EIT can produce giant Kerr non-linearity in the system,which can realize a variety of weak nonlinear optical effects,including efficient multiwave mixing,weak light soliton,and so on.In addition,active control of light field,especially the storage and retrieval of light pulse,can be realized via EIT.As an optical basic device,optical beam splitter plays an important role in the field of light.The beam splitter based on EIT scheme can realize the integration of quantum memory and linear and nonlinear optical function,reaching the applications of photon quantum information and all-optical information processingThe main content of this dissertation is to realize the stable propagation,storage,retrieval,and beam splitting of linear and nonlinear optical pulses in cold atom system or solid materials via EIT.The arrangement is as follows:1.Study on slow-light soliton beam splitters.We propose a scheme to realize slow-light soliton beam splitters by using a tripod-type four-level atomic system.We show that optical solitons,which have ultraslow propagation velocity and ultralow gen-eration power,can be generated in the system via EIT and can be stored and retrieved with high efficiency and fidelity.In particular,a nonlinear beam splitter that splits one optical soliton into two or more ones can be obtained by switching on and off of two or more control laser fields subsequently.The results reported here open a route not only for active manipulation of nonlinear optical pulses in multistate quantum systems but also for promising applications in optical information processing and transmission.2.Study on highly efficient and controllable surface polariton beam splitters.We propose a scheme to realize highly efficient and controllable surface polariton beam splitters with a hybrid system via the EIT of quantum emitters doped near the interface between a metamaterial and a dielectric.By means of the destructive interference effects contributed by the EIT of the quantum emitters and by the electric-magnetic response of the metamaterial,we show that such beam splitters can work at very low light level and they have small quantum decoherence and low Ohmic loss? moreover,the propagation loss of the surface polaritons can be reduced further by using weak microwave fields and the dispersion effect of the surface polaritons can be balanced by using the EIT-enhanced Kerr effect.Therefore,the surface polariton beam splitters obtained here have high splitting efficiency and may be controlled actively.3.Study on storage,retrieval,and splitting of dark solitons and Peregrine solitons.In a ? type atomic system,stable slow-light dark solitons and Peregrine soli-tons with finite continuous wave background can be generated via EIT.It is proved that the dark soliton and Peregrine soliton with continuous background can be stored and retrieved with high efficiency and high fidelity.In addition,we also show that dark solitons and Peregrine solitons can be separated by manipulating two control laser fields in the system of double ? type or tripod type energy levels.4.Study on photon storage and routing in quantum dots with spin-orbit cou-pling.Due to the need of practical application,it is an important topic to realize efficient and high fidelity solid-state quantum memory device.We propose a scheme to realize highly efficient and controllable storage and routing of single photons based on gate defied quantum dots(QDs)with Rashba spin-orbit coupling(SOC)via EIT.Since in gate defined QDs the SOC can be used to mix different Landau levels and spins,many new paths for optical transitions can be acquired.The magnetic field and the SOC in the QDs can be utilized to manipulate the electronic energy gaps.Our research opens a route for designs of advanced solid-state devices promising for applications in photonic quantum-information processing and transmission based on the QDs with SOC.The results obtained in the dissertation make sense not only in nonlinear and quan-tum optics in EIT schemes,but also in the design of new optical devices to realize the stable propagation,storage,retrieval,splitting,and routing of light pulses in cold atoms and quantum dots.