【摘要】 提出了利用四能级原子系统与三个电磁场相互作用获取有效交叉Kerr非线性的方案.应用微扰理论和密度矩阵方法,得到了三阶极化率与外加电磁场失谐量的变化关系.结果表明:当两个弱探测场的失谐量达到拉曼共振时,可以获得一个大的交叉Kerr非线性磁化率,且自Kerr非线性极化率和线性极化率为零.证明了在具有拉曼共振的四能级原子系统中获得无吸收有效交叉Kerr非线性的可行性.更多还原

【Abstract】 A theoretical investigation is put forward for obtaining effective cross-Kerr nonlinearity of the four-level atom interacting with three electromagnetic fields.Using density-matrix equations and perturbation iterative method,the variation dependence of the third-order susceptibility on the detunings of the applied electromagnetic fields is derived.The results show that a large cross-Kerr nonlinearity can be generated when the detunings of the two weak probe fields are Raman resonant,and the corresponding linear susceptibility and self-Kerr interactions vanish.The realization of the effective Kerr nonlinearity with vanishing absorption is possible in a Raman resonant four-level system.更多还原