The Develop Of Magnetic Shielding For Light Storage In Hot Atom Vapor

So far，photon is a most fast and stable information carrier which is widely applied intocommunication science and quantum information field, so how to improve the ability tocontrol photon is of great importance for the development of information technology andcommunication technology.It has been discussed heatedly that Elcctromagnctic inductcdtransparence (EIT) should be used in processing optical information. EIT is an impotrantcffcct of quantum coherent, and quantum coherent, namely atomic cohercnce is the result ofinteraction of coherent electromagnetic Held (clcclroslatic field, microwave, and laser) andatoms. Due to Zeeman Effect, level splitting will occur under the action of a magnetic field. Ifmagnetic field is a little mixed and disorderly, the transition frequency between energy levelswill become unstable, which will have an cffcct on the interaction of atom and photon, so thatit is very important to decrease the stray magnetic intcrfcrcncc. Magneto-static shieldingcavity can wipe off this kind of intcrfcrcncc, and then can provide a clean condition for theinteraction of atom and photon. In this paper，the cavity is developed for quantum opticsexperiments. Base on the cavity, some experiments about quantum optics have been eanredon. The structure of this paper is as follows:Firstly, magnetic shielding theory is discussed. Under National Natural Science Fund, anexcellent magnetic shielding cavity is developed. The material of the cavity is Permalloy.And the structure of the cavity has three layers. Meanwhile in this paper. According to thequantum optics experiment requirement,3-layer nested magnetic shielding is designed andmade, and then its effect has been tested. Under the?50000nT hoirzontal intensity ofgeomagnetic field, the area with its internal intensity below200nT has covercd200mm,which is much longer than51.5mm, the length of Rb cell. This result has met therequirements of the quantum optics expeirment.Secondly, based on the designed magnetic shielding, this paper carrys on some quantumoptics experiments.First, this paper conducts the research on the optical dcflection rotating effect Irom theinteraction of atom and photon: the rotation of optical polarization phenomenon, establishesquantum theory model. The rate equation theory is used for analyzing rcspcctivcly theFaraday rotation, optical polarization self-rotation, and a simple theoertical model of the threerotations is established respectively. Secondly, the paper sets up optics experiment platform, and designs the experiment project to validate the rotation in the three eases to verify thetheory model is correct. Finally, this paper gets the expeirmental results. And theexpeirmental results and theoretical results are compared in this paper, and the two results arevery consistent，which indicates that the Faraday rotation, optical polarization rotation, andthe superposition rotation can be explained by the theoretical model.