中文摘要：

分析了利用双暗态共振之间的相互作用提高Kerr非线性的方案，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相干驱动场失谐量变化的关系．结果表明，随着相干驱动场失谐量的增加，双暗态共振之间干涉使得Kerr非线性的最大值也随之变大且逐渐进入电磁感应透明窗口，并使用缀饰态理论对其产生的机制给予相应的解释．证明了在具有双暗态共振的四能级原子系统中获得无吸收巨Kerr非线性实现的可行性．

英文摘要：

A theoretical investigation was carried out into the program for enhancing the Kerr nonlinearity by interacting double dark states resonances. Using density-matrix equations and perturbative iterative method, the dependence of the real part of the third-order susceptibility on the variation of the additional coherent driving field detuning was derived. It is found that the maximal Kerr nonlinearity induced by interacting dark resonances increases with increment of the detuning and enters gradually the electromagnetically induced transparency window, in which the corresponding linear absorption vanishes, moreover,by utilizing the dressed state theory, physical mechanisms for the results were presented. The realization of the giant Kerr nonlinearity with vanishing absorption is possible in a generic four-level system with double dark resonances.