An all-dielectric nanoantenna is expected to greatly boost the nonlinear performance owing to its large mode volume and low material loss. However, it still suffers from the relatively weak near-field enhancement and the inferior far-field directivity. In this work, by successively introducing an upper metal ring and a bottom metal film, the plasmonic resonance and the perfect electric conductor (PEC) mirror effect are employed to significantly enhance and tailor the third harmonic generation (THG) from the high-index silicon nanoantenna. Numerical results show that benefiting from both of these two metal components, not only the THG efficiency is increased by more than 1 and 3.5 orders of magnitude compared with those with only single metal component and without any metal component, respectively, but also an improved radiation directivity can be obtained. The dependences of geometric parameters are discussed as well. This work suggests a route to enhance and manipulate the nonlinear radiation by a hybrid nanoantenna and facilitates its practical applications such as biosensing and nonlinear light sources.

中文翻译：

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在金属-电介质混合纳米天线中定制来自 Anapole 模式的三次谐波生成


全电介质纳米天线由于其大模式体积和低材料损耗预计将大大提高非线性性能。但其仍然存在近场增强能力相对较弱、远场方向性较差的问题。在这项工作中，通过相继引入上部金属环和底部金属膜，利用等离子体共振和完美电导体（PEC）镜面效应来显着增强和定制高折射率硅的三次谐波产生（THG）纳米天线。数值结果表明，受益于这两种金属组件，与仅有单一金属组件和没有任何金属组件的相比，不仅THG效率分别提高了1和3.5个数量级以上，而且辐射也得到了改善可以获得方向性。还讨论了几何参数的依赖性。这项工作提出了一种通过混合纳米天线增强和操纵非线性辐射的途径，并促进了其在生物传感和非线性光源等实际应用。