González-Colsa Javier, Olarte-Plata Juan D, Bresme Fernando, Albella Pablo
Group of Optics, Department of Applied Physics, University of Cantabria, 39005 Santander, Spain.
Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, London W12 0BZ, U.K.
J Phys Chem Lett. 2022 Jul 7;13(26):6230-6235. doi: 10.1021/acs.jpclett.2c00870. Epub 2022 Jun 30.
High refractive index (HRI) dielectric nanostructures offer a versatile platform to control the light-matter interaction at the nanoscale as they can easily support electric and magnetic modes with low losses. An additional property that makes them extraordinary is that they can support low radiative modes, so-called anapole modes. In this work, we propose a spectrally tunable anapole nanoheater based on the use of a dielectric anapole resonator. We show that a gold ring nanostructure, a priori nonresonant, can be turned into a resonant unit by just filling its hole with an HRI material supporting anapole modes, resulting in a more efficient nanoheater able to amplify the photothermal response of the bare nanoring. As proof of concept, we perform a detailed study of the thermoplasmonic response of a gold nanoring used as heating source and a silicon disk, designed to support anapole modes, located in its center acting as an anapolar resonator. Furthermore, we utilize the anapole excitation to easily shift the thermal response of these structures from the shortwave infrared range to the near-infrared range.
高折射率（HRI）介电纳米结构提供了一个通用平台，可在纳米尺度上控制光与物质的相互作用，因为它们能够轻松支持低损耗的电模式和磁模式。使其与众不同的另一个特性是它们能够支持低辐射模式，即所谓的无偶极模式。在这项工作中，我们基于介电无偶极谐振器的使用提出了一种光谱可调谐的无偶极纳米加热器。我们表明，一个先验非谐振的金环纳米结构，只需用一种支持无偶极模式的HRI材料填充其孔洞，就能转变为一个谐振单元，从而得到一个更高效的纳米加热器，能够放大裸纳米环的光热响应。作为概念验证，我们对用作加热源的金纳米环和位于其中心作为无偶极谐振器的硅盘（设计用于支持无偶极模式）的热等离子体响应进行了详细研究。此外，我们利用无偶极激发轻松地将这些结构的热响应从短波红外范围转移到近红外范围。
