电磁感应透明介质中的弱光空间暗孤子环

利用多重尺度方法，解析地研究了Λ型三能级冷原子气及一束较强耦合光组成的电磁感应透明介质体系中的非线性动力学性质.结果表明：一束较弱的探测光能在电磁感应透明介质中形成弱光空间暗孤子，当弱光空间暗孤子沿轴向传播时，它会逐渐演化成一个稳定的弱光空间暗孤子环，这是衍射效应和自散焦效应相互平衡的结果. 关键词： 电磁感应透明 弱光空间暗孤子环 多重尺度方法

Spatial weak-light ring dark solitons in an electromagnetically induced transparency medium

By using multiple-scale method，we analytically study the nonlinear dynamical properties of an electromagnetically induced transparency medium with three-level atoms and a strong coupling light field. It is shown that a weak probe light beam can form spatial weak-light dark solitons. When it propagates along axial direction，the dark soliton will transforms into a steady spatial weak-light ring dark soliton，which results from the balance of the interplay between beam diffraction and refractive nonlinearity.