【作者】 校金涛；

【导师】 王海；

【作者基本信息】 山西大学 ， 原子与分子物理， 2008， 硕士

【摘要】 本文的主要研究内容包括两个方面:(1)研究了Tripod-型原子系统中EIT增强的交叉Kerr非线性效应。(2)通过改进Rb原子磁光阱系统提高了冷却光功率;扩大了冷却光直径,提高了冷原子数目,并研究了冷原子光学密度与MOT系统参量的关系。具体研究内容有:(一)使用半经典理论计算了四能级Tripod-型原子系统中触发光引起的EIT吸收和色散的变化。结果表明,当触发光作用于该四能级系统时,可使探针光的EIT窗口(由耦合光导致)变大(吸收减小),同时色散峰值变大。EIT处吸收的降低和色散的增强依赖于触发光的功率。这种交叉Kerr非线性效应在偏振量子相位门的研究中具有应用潜力。(二)建立了激光放大系统。使用一台主激光器注入锥型光功率放大器获得了功率为640mW,波长为780nm(单频,窄线宽)的激光输出。(三)将冷却光光斑直径扩大为40mm,由于冷却区域的增大,提高了冷原子数目。研究了冷原子数和光学密度与MOT系统参量的关系,为下一步获得高密度冷原子团开展冷原子中相干效应的研究工作提供了基础。更多还原

【Abstract】 This dissertation is organized in the following way.First,we have researched the cross-phase Kerr nolinearity effect in tripod-type atomic system;then introduced MOT system(rubidium atom) and improved it, enlarged the diameter of trap beam for rising the number of cold atoms,and finally studied the dependence of optical density of cold atoms on MOT systematic parameters.The works of this dissertation have three parts:(1) The susceptibility of the probe field in a four-level tripod-type atomic system as a function of the probe detuning is calculated.The results show that the absorption and dispersion of probe field near EIT resonance can be significantly changed,when a trigger beam interacting with a transition in this system.With the increase of Rabi frequency of trigger beam,the absorption of probe beam at EIT window becomes smaller,and its dispersion becomes larger.Such changes of susceptibility of probe beam caused by a trigger beam are corresponding to the third Kerr nonlinearity, which have an application in polarization phase gate.(2) We achieved a 780nm(single frequency,narrow linewidth),640mW laser beam by injecting into one TPA amplifer using one DL100 master laser.(3) Meanwhile,rising the diameter of trap beam up to 40mm we obtained more numbers of cold atoms and thereafter,studied the relationship between the number of cold atoms and optical density and systematic parameters of MOT for next work.更多还原