掺镨硅酸钇晶体中基于电磁感应透明的光脉冲存储与处理

发布时间：2018-04-11 14:39

本文选题：电磁感应透明 + 掺镨硅酸钇　；参考：《南开大学》2013年博士论文

【摘要】：由相干光场与原子(分子)相互作用引起的原子相干效应是当前光学研究的热点领域,利用原子相干效应对光场携带的信息进行存储和处理是其中的一个重要研究内容。在各种原子相干效应之中,电磁感应透明效应相关的研究尤为引人注意。由于电磁感应透明效应具有强色散、强非线性等特点,并且可以通过外部参数来调控,因此它在光脉冲群速度减慢及存储、量子信息存储与处理以及非线性效应等领域具有广阔的应用前景。本论文建立在电磁感应透明效应机制下的光脉冲的存储及读取基础之上,对光脉冲的存储和读取过程中的相位匹配条件、相位共轭波的产生、光涡旋所携带的拓扑电荷的存储和处理等内容进行了详细的分析及研究。首先,我们在理论上分析了光脉冲基于电磁感应透明效应的存储和读取过程存在的角度选择现象,结果表明角度选择性与相位匹配相关。设计了一个共焦实验系统,通过测量光脉冲的读取效率与角度失配和频率失配的关系曲线,对相位匹配条件进行了表征,并对其应用前景做了论述。其次,我们对基于电磁感应透明效应产生相位共轭波的过程进行了详细的理论分析,然后通过设计实验配置,采用对光脉冲正向存储和反向读取的方法,成功地产生了一束非简并共轭波,对其修复相位扰动的功能进行了演示,并研究了相位共轭波的反射率与读取光光功率密度的关系。最后对这一过程中的相位匹配条件,即相位共轭波的反射率与角度失谐、频率失谐的关系进行了分析和研究。最后,我们对基于电磁感应透明效应的光涡旋的存储和读取进行了理论分析和实验研究。由于光涡旋携带的轨道角动量(即拓扑电荷数)是高维量子化的,因此可看做对光涡旋携带的高维信息的存储。通过将参与光脉冲存储和读取相互作用的三束光调制成涡旋光,可以将光涡旋的轨道角动量从原光场转移到读取出来的信号光场当中,以实现信号的转移和处理。最后我们通过设计实验,成功演示了光涡旋携带的轨道角动量在光脉冲存储和读取过程中的转移。通过这种方法,可以对存储的信息进行逻辑操作(逻辑门)或者(高维)信息处理。
[Abstract]:The atomic coherence effect caused by the interaction between coherent light field and atom (molecule) is a hot field of optical research. The use of atomic coherence effect to store and process the information carried by optical field is one of the important research contents.Among all kinds of atomic coherence effects, the study of electromagnetic induction transparency effect is particularly interesting.Because the electromagnetically induced transparency effect has the characteristics of strong dispersion, strong nonlinearity, and can be controlled by external parameters, it slows down and stores in the optical pulse group.Quantum information storage and processing as well as nonlinear effects and other fields have a broad application prospects.This paper is based on the storage and reading of optical pulse under the mechanism of electromagnetic induction transparency, the phase matching condition and the generation of phase conjugate wave in the process of storage and reading of optical pulse.The storage and processing of topological charge carried by optical vortex are analyzed and studied in detail.Firstly, we theoretically analyze the angle selection phenomenon in the storage and reading process of optical pulse based on the electromagnetic induction transparency effect. The results show that the angle selectivity is related to the phase matching.A confocal experimental system is designed. The phase matching condition is characterized by measuring the relation curves between the reading efficiency and angle mismatch and frequency mismatch of optical pulse, and its application prospect is discussed.Secondly, we analyze the process of phase conjugate wave based on the effect of electromagnetic induction transparency in detail, and then design the experimental configuration, and adopt the method of forward storage and reverse reading of optical pulse.A nondegenerate conjugate wave is successfully produced and its function of repairing phase disturbance is demonstrated. The relationship between the reflectivity of the phase conjugate wave and the optical power density is studied.Finally, the relationship between reflectivity of phase conjugate wave and angle detuning and frequency detuning is analyzed and studied.Finally, the storage and reading of optical vortex based on electromagnetic induced transparency are studied theoretically and experimentally.Because the orbital angular momentum (i.e. topological charge number) carried by the optical vortex is high-dimensional quantization, it can be regarded as the storage of the high-dimensional information carried by the optical vortex.The orbital angular momentum of the optical vortex can be transferred from the original light field to the signal light field in order to realize the signal transfer and processing by modulating the three beams of light involved in the optical pulse storage and reading interaction into vortex light.Finally, we successfully demonstrate the transfer of orbital angular momentum carried by optical vortex during the process of optical pulse storage and reading.In this way, the stored information can be logically operated (logic gate) or (high-dimensional) information processing.
【学位授予单位】：南开大学
【学位级别】：博士
【学位授予年份】：2013
【分类号】：O441.3;TP333

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