非线性光学作为现代光学和光子学的重要组成部分,在诸多方面有着重要的研究意义和应用前景。然而,在微纳尺度,受限于固有的非线性极化率和有限的相互作用长度,材料的非线性光学响应十分微弱,制约了可集成的微纳非线性光电子器件的发展。近年来,研究人员将表面等离激元的亚波长电磁场束缚特性和非线性光学结合起来,使得弱光非线性效应在微纳结构中得以实现,并逐渐形成了一个新的研究领域,即非线性表面等离激元光子学。区别于以往侧重关注表面等离激元金属纳米结构本身的非线性光学效应,重点综述了金属纳米结构和电介质材料组成的复合体系中非线性光学效应的最新进展。介绍了表面等离激元和非线性光学的相关性质和理论背景,然后分别从零维复合体系中的非线性光学增强效应、一维复合波导中的非线性效应、二维石墨烯中的非线性等离激元等方面重点介绍了相关研究进展,最后展望了非线性表面等离激元未来的研究方向,机遇和挑战。

As an important part of modern optics and photonics, nonlinear optics plays a significant role in both research and application. However, at the micrometer and nanometer scales, the nonlinear optical response of a material is generally weak owing to the inherent nonlinear susceptibility and limited interaction length of the material; this restricts the development of integrated nanoscale nonlinear optoelectronic devices. In recent years, by taking advantage of the ability of surface plasmons to confine the electromagnetic field into a subwavelength volume, researchers have observed the nonlinear optical effects in the micro/nano-structures under the weak excitation light. This has gradually led to the formation of a new research field: nonlinear plasmonics. Different from previous review articles that have focused more on the nonlinear optical properties of the plasmonic metal nanostructures, in this paper, we emphasize the recent progress of nonlinear optical effects in hybrid metal-dielectric systems. First, we introduce the related properties and theoretical background of plasmonics and nonlinear optics; then, we summarize researches related to nonlinear optical enhancement effects in zero-dimensional hybrid systems, nonlinear effects in one-dimensional hybrid systems, nonlinear plasmonics in two-dimensional graphene, respectively. Finally, we discuss future research directions in the field of nonlinear plasmonics and significant opportunities and challenges.