Solid-state Quantum Memory And Its Application Research In Quantum Repeater

Quantum repeater is the basis of making quantum network into practical use, and the core component inside of quantum repeater is quantum memory. Light quantum storage is different from the classical information storage because of no-cloning theorem. Now, a series of quantum memory schemes have been proposed, such as Faraday rotation, electromagnetically induced transparency, off-resonant Raman transitions, and photon echoes. Photon echo technique is widely used because of its advantages in storage efficiency in solid materials and multimode memory capacity.The entangled state shows its irreplaceable in the process of information transmission as the important effect of the transmission of quantum information.Because of the proposing of DLCZ scheme,the long distance transmission of entangled state, which uses a simple physical system to achieve the requirements of quantum repeater, becomes possible. So it’s needed to add photon source which can produce entangled photon pairs into a quantum repeater. However, it’s difficult to set entangled photon source into a quantum repeater, thus bringing a lot of restrictions on the actual application.In this thesis, we started from the basic principle of light-atoms interaction, and deduced the evolution equations of light and atoms. Secondly, we detailedly study the quantum memories based on controlled reversible inhomogeneous broadening(CRIB). We then proposed a scheme to realize solid-state memory entanglement using the theory that atomic ensemble could produce entanglement and improved traditional quantum repeater, on the basis of the controllable inverse inhomogeneous broadening(CRIB) storage technology. In this scheme, two photons were acting on the respective solid-state memory and becomed entangled. After this, two-photon state will be mixed in the beam splitter and achieve entanglement swapping. In the producing process of entanglement in the soild state memory, we could finally calculate the establishment of the scheme, throug detailed deducing of the successfully detecting of the photon in the detector. Our result is of great significance in theory and laboratory, because on the one hand it can save the quantum of resources, on the other hand it can also simplify the experimental operation.