Enhanced four-wave mixing with nonlinear plasmonic metasurfaces.
Enhanced four-wave mixing with nonlinear plasmonic metasurfaces.
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DOI：
10.1038/srep28746
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发表时间：
2016-06-27
影响因子：
4.6
通讯作者：
Argyropoulos C
中科院分区：
文献类型：
--
作者：
Jin B;Argyropoulos C
等离子体超颖表面提供了一种有效的方式来提高几种非线性过程的效率，同时保持纳米尺度。在这项工作中，提出了基于加载克尔非线性材料的膜耦合银纳米条的非线性超表面来实现高效的四波混频（FWM）。高度局域化的等离子体共振在金属膜和纳米条之间的纳米间隙中形成。在这个亚波长的纳米区域的局部电场显着增强。这些性质与由于银区域而导致的松弛的相位匹配条件相结合，导致巨大的FWM效率，与裸银屏幕相比，其提高了十九个数量级。此外，有效的可见光和低太赫兹源可以构建基于所提出的非线性超表面。四波混频产生的相干波具有方向性，其输出功率对激发源的入射角相对不敏感。该辐射功率可以通过增加激励功率来进一步增强。置于纳米间隙中的介电非线性材料是产生超强四波混频响应的主要原因。基于所提出的非线性超颖表面设计，可以设想设计跨越不同频率范围的紧凑且高效的波混频器和光源。
Plasmonic metasurfaces provide an effective way to increase the efficiency of several nonlinear processes while maintaining nanoscale dimensions. In this work, nonlinear metasurfaces based on film-coupled silver nanostripes loaded with Kerr nonlinear material are proposed to achieve efficient four-wave mixing (FWM). Highly localized plasmon resonances are formed in the nanogap between the metallic film and nanostripes. The local electric field is dramatically enhanced in this subwavelength nanoregion. These properties combined with the relaxed phase matching condition due to the ultrathin area lead to a giant FWM efficiency, which is enhanced by nineteen orders of magnitude compared to a bare silver screen. In addition, efficient visible and low-THz sources can be constructed based on the proposed nonlinear metasurfaces. The FWM generated coherent wave has a directional radiation pattern and its output power is relatively insensitive to the incident angles of the excitation sources. This radiated power can be further enhanced by increasing the excitation power. The dielectric nonlinear material placed in the nanogap is mainly responsible for the ultrastrong FWM response. Compact and efficient wave mixers and optical sources spanning different frequency ranges are envisioned to be designed based on the proposed nonlinear metasurface designs.