Abstract For p-polarized light incident on an interface between an ordinary dielectric and an epsilon-near-zero (ENZ) material, an enhancement of the component of the electric field, normal to this interface, has been shown to occur. This local field enhancement holds great promise for amplifying nonlinear optical processes and for other applications requiring ultrastrong local fields in epsilon-near-zero based technologies. However, the loss associated with the imaginary part of the dielectric constant of an epsilon-near-zero material can greatly suppress the field enhancement factor. In this study, we analyze, using density matrix formalism, the field enhancement factor for a saturable two-level system that exhibits second- and third-order nonlinearities. We show that, in such a system, an almost lossless ENZ response can arise as a consequence of saturable nonlinearity and that the local field enhancement factor can be readily controlled dynamically by adjusting the intensity of the incident electromagnetic wave. Our findings provide for the first time a pathway to design a material exhibiting an external field responsive epsilon-near-zero behavior for applications in nonlinear photonics.

中文翻译：

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通过 epsilon 近零介质的非线性动态控制 epsilon 近零/介电界面处的局部场增强

摘要 对于入射在普通电介质和 epsilon-near-zero (ENZ) 材料之间的界面上的 p 偏振光，已表明会发生垂直于该界面的电场分量的增强。这种局部场增强对于放大非线性光学过程以及在基于 epsilon 近零的技术中需要超强局部场的其他应用具有很大的希望。然而，与ε接近零材料的介电常数的虚部相关的损耗可以极大地抑制场增强因子。在这项研究中，我们使用密度矩阵形式分析了具有二阶和三阶非线性的可饱和双级系统的场增强因子。我们证明，在这样的系统中，由于可饱和非线性，可以产生几乎无损的 ENZ 响应，并且可以通过调整入射电磁波的强度轻松地动态控制局部场增强因子。我们的研究结果首次提供了一种设计材料的途径，该材料表现出外场响应 epsilon-near-zero 行为，适用于非线性光子学。