The Study Of Spatially Multimode Quantum Memory And Quantum Image Memory Using Atomic Ensemble

Since some excellent properties of light, such as speed, ease ofcoding, it has been a good vehicle for the dissemination of informationmankind. With quantum mechanics in particular, the development ofquantum optics, the nature of the light is aware more profound. Becausethe quantum information is encoded with a very great advantages，peoplenaturally think of how information is encoded into photons and applythem to quantum computers and quantum information networks. So howwill the optical quantum information stored is also a very important partof realization of a quantum computer and building a quantum network.This paper is to study how to use the interface of light and the atomicensemble to store quantum information on the atomic ensemble.This paper introduces the description quantum polarization light andthe description of polarized atomic ensemble in a continuous variablesystem especially polarization squeezed states, polarization entanglementand spin squeezed states, forms of expression criterion spin entangledstate. Interaction between light and atoms from the ensemble deduced three polarized spin state with atomic ensemble interaction thatBeam-split interaction, Parametric-gain interaction, and Faradayinteractions. Since then three kinds of light and the atomic ensembleinterplay. We further introduced the use of polarized atomic ensemblequantum holographic storage, and use of two atoms to store a bunch ofpolarized ensemble sideband entangled light. Space multimode opticalquantum information storage has good robustness, fast speed and theability to store high-density storage, for improving the speed of quantumcommunication and quantum computing to reduce the difficulty has animportant role in recent years attracted the interest of various researchgroups, especially quantum images stored on the experiment after anotheris implemented various programs. The study of some non-classicalproperties of the image storage is still relatively lacking, so this paperintroduces the definition of the quantum correction of the image in thethird chapter, and produce images of quantum entanglement experimentsusing four-wave mixing method, we try to put the final using twoentangled atomic ensemble store programs and changes in theory fidelityand stored before and after analysis of the degree of entanglement stored.On the basis of these theories, this paper mainly of two parts：(1) We analysis the degree of entanglement of entangled photonpairs are stored before and after storage. Explores the relationshipbetween the detuning storage entanglement, through theoretical calculations we found that with increasing detuning, the performance ofthe storage model to save entanglement better.(2) We use four-wave mixing method produces two entangledimages and analyzes the relationship the degree of entanglement ofentangled images with the coupling constants and the length of the crystal.By adjusting these two parameters can prepare perfect entanglement.Then we store the two entangled images using two atom ensemblerespectively. We analyzed the degree of entanglement the two entangledimages, before and after the storing and reading process.