Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low heat conversion.
Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low heat conversion.
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DOI：
10.1038/ncomms8915
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发表时间：
2015-08-04
影响因子：
16.6
通讯作者：
Maier SA
中科院分区：
文献类型：
--
作者：
Caldarola M;Albella P;Cortés E;Rahmani M;Roschuk T;Grinblat G;Oulton RF;Bragas AV;Maier SA
纳米等离子体学最近彻底改变了我们在纳米尺度上控制光的能力。使用具有定制形状的金属纳米结构，可以有效地将光聚焦到纳米尺度的场“热点”上。在这种光学纳米天线中实现了高场增强因子，使单分子相互作用、高度增强的非线性和纳米尺度波导领域的科学变革成为可能。不幸的是，这些巨大的增强是以金属吸收造成的高光学损耗为代价的，严重限制了实际应用。通过实现一种基于介电纳米结构的新型纳米光子平台，形成具有超低光-热转换的高效纳米天线，我们展示了一种克服这些限制的方法。我们发现，类二聚体硅基单纳米天线产生高表面增强荧光和表面增强拉曼散射，同时在其热点和周围环境中产生可忽略不计的温度升高。金属纳米天线可以增强和限制电磁场，但局部加热阻碍了许多应用。在这里，Caldarola等人使用硅二聚体纳米天线展示了高近场增强和超低热转换在可见-近红外区域的20 nm间隙。
Nanoplasmonics has recently revolutionized our ability to control light on the nanoscale. Using metallic nanostructures with tailored shapes, it is possible to efficiently focus light into nanoscale field ‘hot spots'. High field enhancement factors have been achieved in such optical nanoantennas, enabling transformative science in the areas of single molecule interactions, highly enhanced nonlinearities and nanoscale waveguiding. Unfortunately, these large enhancements come at the price of high optical losses due to absorption in the metal, severely limiting real-world applications. Via the realization of a novel nanophotonic platform based on dielectric nanostructures to form efficient nanoantennas with ultra-low light-into-heat conversion, here we demonstrate an approach that overcomes these limitations. We show that dimer-like silicon-based single nanoantennas produce both high surface enhanced fluorescence and surface enhanced Raman scattering, while at the same time generating a negligible temperature increase in their hot spots and surrounding environments. Metallic nanoantennas can enhance and confine electromagnetic fields, however, localized heating hinders many applications. Here, Caldarola et al. demonstrate both high near-field enhancement and ultra-low heat conversion in the visible-near infrared region using silicon dimer nanoantennas with 20 nm gaps.