Modulation Of Cross Phase Modulation Based On Electromagneticallv Induced Transparency By A Microwave

In the1990s, S.E.Harris and others firstly discovered electromagneticinduction transparency (EIT), which leaded to remarking development in relatedfields. EIT phenomenon refers to the transparency for a probe field propagating throughthe multi-level atoms which are driven by a strong field. The characteristics of EITtechnique mainly have two aspects: one is its pulse propagation characteristics, the otherone is its optical properties. The pulse propagation characteristic is that the lightpropagates through the atomic medium with a very slow group velocity or a zerovelocity. This can be used in quantum information storage, etc. The optical propertiesare associated with gain without inversion, coherent population transfer, giant nonlinearoptics, etc. These properties are useful in the preparation of entangled state, all-opticalswitch, quantum communication and so on. Especially, the nonlinear optical phenomenaat a lower level of photons such across-Kerr nonlinear optics or cross phasemodulation can be applied in quantum phase logic gate， quantum nondemolitionmeasurement, quantum communication and so on. We have investigated the effects ofthe decohenrence and microwave fields on the cross phase modulation in the invertedY-scheme atomic system. The structure of this paper is arranged as follows:In the first chapter, we have briefly introduced the basic theory and development ofthe electromagnetic induction transparency, and used a three-level atomic system tointroduce EIT phenomenon as well as its applications.In the second chapter, the basic theory of interaction between light and matter hasbeen in detail introduced. This includes how to write the Hamiltonian of the interaction.Two basic methods, i.e. the probability amplitude method and the density matrixmethod to study the interaction between light and matter are briefly displayed.In the third chapter, the cross phase modulation in several atomic systems is reviewed.In the fourth chapter，we have investigated the effects of the incoherent populationexchange of decoherence mechanisms on the cross-Kerr nonlinearity in the invertedY-scheme atomic system. The little population exchange can result in a cross-Kerrnonlinear gain and make the slope of the corresponding dispersion curve much deeper.A large cross-Kerr nonlinearity without nonlinear absorption can be realized in thepresence of the population exchange in the present scheme. This is useful inimplementing quantum phase gates by using optical nonlinearity based on the techniqueof EIT.In fifth chapter, we have applied a microwave to drive the transition collected by theground states in the inverted Y-scheme atomic system, and investigated the effects ofthe microwave field on the cross-Kerr absorption and dispersion. It is found that thestrength of a microwave field can affect the nonlinear absorption and the nonlineardispersion, and these nonlinear properties are dependent on the relative phase among theprobe, trigger and control fields.