J4 ›› 2010, Vol. 27 ›› Issue (4): 435-440.

• 非线性光学 • 上一篇    下一篇

RY型四能级原子系统中增强的交叉Kerr非线性

严祥安1,2,刘汉臣1,王秋萍1   

  1. 1. 西安工程大学理学院,陕西,西安 710048;
    2. 西安交通大学电子物理与器件教育部重点实验室,陕西,西安 710049
  • 收稿日期:2009-07-27 修回日期:2009-10-09 出版日期:2010-07-28 发布日期:2010-06-13
  • 通讯作者: 严祥安(1980-),女,讲师,西安工程大学教师,现正在西安交通大学攻读博士学位,主要从事非线性光学的研究。 E-mail:yxa@stu.xjtu.edu.cn
  • 基金资助:

    国家自然科学基金(60678005),高等学校博士学科点专项基金(20050698017)和西安工程大学校管科研项目(09XG25)

Enhanced cross Kerr nonlinearity in a RY-type four-level atomic system

YAN Xiang-an1,2, LIU Han-chen1, WANG Qiu-ping1   

  1. 1. School of Science, Xi’an Polytechnic University, Xi’an 710048, China; 
    2. Key Laboratory for physical Electronics and Devices of the ministry of Education, Xi’an Jiaotong University, Xi’an 710049, China
  • Received:2009-07-27 Revised:2009-10-09 Published:2010-07-28 Online:2010-06-13

摘要:

在理论上研究了RY型四能级原子系统中的交叉Kerr非线性效应。采用微扰理论和密度矩阵方法导出三阶极化率实部随外加的相干耦合场强度和原子两基态间的无辐射衰减系数之间的关系。结果表明,在双光子Raman共振处,通过减小原子两基态间的无辐射衰减系数和提高外加的相干耦合场的强度,可以获得无吸收增强的交叉Kerr非线性效应。该研究结果在全光学开关上有着重要的应用潜力.

关键词: 非线性光学, 电磁感应透明, 交叉Kerr非线性效应

Abstract:

A theoretical program is studied on the cross Kerr nonlinearity effect in RY-type four-level atomic system. Using density-matrix equations and perturbative iterative method, the dependence of the real part of the third-order susceptibility on the variations of the additional coherent coupling field intensity and the nonradiative decay rate between the two ground states of the atoms is derived. It is found that, by decreasing the nonradiative decay rate between the two ground states and increasing the coupling field intensity, the enhanced cross Kerr nonlinearity with vanishing absorption can be obtained at two-photon Raman resonance. The research result has useful application in all-optical switch.

Key words: nonlinear optics, electromagnetically induced transparency, cross Kerr nonlinearity effect