Electric and Magnetic Field Enhancement with Ultralow Heat Radiation Dielectric Nanoantennas: Considerations for Surface-Enhanced Spectroscopies
Electric and Magnetic Field Enhancement with Ultralow Heat Radiation Dielectric Nanoantennas: Considerations for Surface-Enhanced Spectroscopies
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DOI：
10.1021/ph500060s
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发表时间：
2014-06-01
期刊：
影响因子：
7
通讯作者：
Maier, Stefan A.
中科院分区：
文献类型：
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作者：
Albella, Pablo;Alcaraz de la Osa, Rodrigo;Maier, Stefan A.
已知等离子体结构提供电场的强局部增强，用于与其附近的分子和材料相互作用。然而，它们固有地遭受高损耗和吸收，这可能发生在粒子中的表面等离子体激元和局部等离子体激元中，我们将关注于此。这些损失的影响，以及经常被忽视的一个方面，是由于入射辐射的吸收和转换成热能而导致的纳米颗粒的局部加热。由于介质和纳米颗粒本身的光学性质的变化，纳米颗粒温度的增加以及周围介质的增加可以直接破坏系统的响应。这在物质的光谱分析中尤其是一个问题，其中由于等离子体效应引起的场增强的优点可能被影响样品的纯电磁响应的局部温度增加所阻碍（或妨碍）。在这里，我们调查使用的亚波长结构制成的高折射率超低损耗的光学和近红外制度，磷化镓（GaP）在这种情况下，作为一种新的方式来接近应用程序，需要近场和远场增强，如表面增强拉曼光谱，但与不扰动的响应下评估由于局部加热的样品的特性。特别是，我们显示了近场和远场增强性能的等离子体二聚体与一个从类似的结构制成的磷化镓的比较。这项研究开辟了新的可能性，以克服在纳米光子学和超材料的一系列应用中与等离子体纳米结构相关的损失和发热问题。
Plasmonic structures are known to offer strong local enhancements of the electric field for interaction with molecules and materials in their vicinity. However, they inherently suffer from high losses and absorption, which can occur in both surface plasmon polaritons and localized plasmons in particles, on which we shall focus. An effect of those losses, and an aspect often neglected, is the local heating of the nanoparticle due to the absorption of incident radiation and the transduction into thermal energy. This increase in the nanoparticle temperature, and in turn in the surrounding medium, can directly disrupt the response of the system due to changes in the optical properties of the medium and nanoparticle itself. This is especially a problem in the spectroscopic analysis of matter, where the advantage of field enhancement due to the plasmonic effect can be obstructed (or hampered) by a local temperature increase affecting the pure electromagnetic response of the sample. Here we investigate the use of subwavelength structures made of high refractive index dielectrics with ultralow losses in the optical and near-IR regime, gallium phosphide (GaP) in this case, as a novel way to approach applications that require near- and far-field enhancement, such as surface-enhanced Raman spectroscopy, but with the peculiarity of not perturbing the response of the sample under evaluation due to local heating. In particular, we show a comparison of the near- and far-field enhancing performance of plasmonic dimers with the one obtained from similar structures made of GaP. This study opens new possibilities to overcome losses and heat generation issues associated with plasmonic nanostructures in a range of applications in nanophotonics and metamaterials.