Plasmonic nanocomposites have been extensively studied for over 3 decades. According to early theoretical studies, a large enhancement of nonlinear response has been predicted. Nonetheless, the promised enhancement of coherent or Kerr-type nonlinearities incurs major limitations related to strong absorption and saturation effects. Accordingly, diffraction-limited interactions and long-scale propagation in ultrafast timescales are undermined despite nanoscale-localized electronic field enhancement. Seemingly only nanometric devices operating at low intensity regimes are benefitted from the foresaid effect. Nonetheless, numerous studies have still exploited configurable properties of the nonlinear response of plasmonic nanocomposites, such as nonlinear absorption, high-order nonlinearities, and diffusive nonlinearities for the development of novel processes within the framework of nonlinear wave propagation described by effective medium properties. In this review, the most recent developments on the understanding of the nonlinear response of metals and plasmonic nanocomposites in various temporal regimes are presented. Furthermore, a synthesis of their experimentally determined third-order properties obtained by various experimental techniques, along with practical considerations, is provided. Computational models used for the formulation of nonlinear wave propagation in plasmonic nanocomposites are subsequently presented, corresponding to applicable concepts. Most recent related applications are concisely summarized, indicating the directions of increasing interest in the field, and outlining shortcomings.

中文翻译：

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等离子纳米复合材料中激光的非线性传播

等离子体纳米复合材料已被广泛研究了 3 多年。根据早期的理论研究，已预测非线性响应会大幅增强。尽管如此，相干或克尔型非线性的承诺增强会导致与强吸收和饱和效应相关的主要限制。因此，尽管纳米级局部电场增强，但超快时间尺度中的衍射限制相互作用和长尺度传播受到破坏。似乎只有在低强度条件下工作的纳米器件才能从上述效果中受益。尽管如此，许多研究仍然利用等离子体纳米复合材料的非线性响应的可配置特性，例如非线性吸收、高阶非线性、和扩散非线性，用于在由有效介质特性描述的非线性波传播框架内开发新过程。在这篇综述中，介绍了理解金属和等离子体纳米复合材料在各种时间范围内的非线性响应的最新进展。此外，还提供了通过各种实验技术获得的实验确定的三阶特性的综合，以及实际考虑。随后提出了用于制定等离子体纳米复合材料中的非线性波传播的计算模型，对应于适用的概念。简要总结了最近的相关应用，指出了对该领域越来越感兴趣的方向，并概述了缺点。