Storage And Processing Of Light Pulses Based On Electromagnetically Induced Transparency Effect In Praseodymium Doped Yttrium Silicate Crystal

Atomic coherence induced by the interaction between the coherent light field and atoms (molecules), especially the related information storage and processing, has at-tracted intensive attentions during the recent years. Among them, novel effects based on electromagnetically induced transparency (EIT) effect are of special interest. It could be applied to many potential applications in areas such as nonlinear optics, light group velocity control and quantum information storage/process because of its sharp disper-sion slope, giant optical nonlinearity, and optical-field-based tunability.This dissertation is based on the storage and retrieval of light pulses through elec-tromagnetically induced transparency effect. The results include the phase matching condition for the storage and retrieval of light pulses, the generation of the phase conju-gate wave, and the storage and processing of the topological charges carried by optical vortex.Firstly, we present theoretical analysis about the angular selectivity during the s-torage and retrieval of light pulses based on the EIT effect, and confirm that the angular selectivity is caused by the phase matching requirement. We have designed a confocal configuration to characterize the phase matching condition by measuring the depen-dence of the retrieval efficiency of light pulse with the angular/frequency mismatching. Possible applications based on the phase matching mechanism are discussed.Next, we have generated a non-degenerate phase conjugate wave based on the phase matching condition by using the storage and retrieval of light pulses through EIT effect. This process is analysed theoretically in detail first, and then the experimental scheme is designed. The phase conjugate wave is generated by reading out the stored light pulse at the opposite direction of the coupling beam. We have demonstrated the phase front reconstruction ability of the phase conjugate wave and studied the retrieval power dependence of the reflectivity of the phase conjugate wave. The phase matching requirement during this process is characterized by measuring the dependence of the reflectivity on the angular/frequency mismatching. Finally, we have studied both theoretically and experimentally the storage and pro-cessing of the high dimension information carried by optical vortex based on the EIT-induced storage and retrieval of light pulses. By modulating the interacting beams into optical vortex beams during the storage and retrieval process, the orbital angular mo-mentum is able to be transferred from the recording or reading beams to the retrieved signal beam, which results in the transfer and processing of information. We have ex-perimentally demonstrated the transfer of orbital angular momentum among different beams. More over, logical or addition/subtraction operations based on the angular mo-mentum transfer among the interacting beams have also been experimentally realized.