Abstract We consider a planar defect in the crystal characterized by a change in optical nonlinearity. In the proposed model the sign of the Kerr nonlinearity coefficient is changed abruptly when the field amplitude exceeds the threshold value of the switching field. The theoretical analysis is based on a generalized nonlinear Schrodinger equation with a nonlinear stepwise term and a short-range potential modeling a local interaction between the interface and the excitations. We obtain three new types of nonlinear localized states described by exact solutions of an extended version of the nonlinear Schrodinger equation. We analyze the existence condition of the localized states depending on the interaction strength between interface and excitations. We find that the field distribution localized in the crystal with changing defocusing nonlinearity to self-focusing one is characterized only by one maximum in the case of attractive interface, and by two maxima in the case of repelling interface. We calculate the total power flow along the interface. The possibility of power flow redistribution between crystal regions with interaction strength is shown.

中文翻译：

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晶体界面附近场定位的新特性，其特征在于非线性自聚焦和散焦类型之间的突然变化

摘要 我们考虑以光学非线性变化为特征的晶体中的平面缺陷。在所提出的模型中，当场幅度超过开关场的阈值时，克尔非线性系数的符号会突然改变。理论分析基于广义非线性薛定谔方程，该方程具有非线性逐步项和模拟界面和激发之间局部相互作用的短程电位。我们获得了由非线性薛定谔方程的扩展版本的精确解描述的三种新型非线性局部化状态。我们根据界面和激发之间的相互作用强度分析局部状态的存在条件。我们发现，随着离焦非线性变化为自聚焦，晶体中的场分布在吸引界面的情况下只有一个最大值，在排斥界面的情况下只有两个最大值。我们计算沿界面的总功率流。显示了具有相互作用强度的晶体区域之间功率流重新分配的可能性。