Narrow band perfect absorber for maximum localized magnetic and electric field enhancement and sensing applications.
Narrow band perfect absorber for maximum localized magnetic and electric field enhancement and sensing applications.
复制标题
窄带完美吸收体，适用于最大局部磁场和电场增强和传感应用
DOI：
10.1038/srep24063
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发表时间：
2016-04-05
影响因子：
4.6
通讯作者：
He S
中科院分区：
文献类型：
--
作者：
Yong Z;Zhang S;Gong C;He S
血浆提供了一种令人兴奋的方式，可以介导光与物质之间的相互作用，从而使强大的场所增强和限制，大损失和散射，但是，由于固有的高度，超纳罗带的简单现实是完美的抽象和电磁场增强的挑战金属中的光损耗和辐射阻尼。偏振不敏感的吸收超过99％。大约10-4×（λres/n）3的体积。吸收对最大场的增强至关重要。抽象和局部现场增强，并在生物传感器，过滤器和非线性光学元件中具有潜在的应用。
Plasmonics offer an exciting way to mediate the interaction between light and matter, allowing strong field enhancement and confinement, large absorption and scattering at resonance. However, simultaneous realization of ultra-narrow band perfect absorption and electromagnetic field enhancement is challenging due to the intrinsic high optical losses and radiative damping in metals. Here, we propose an all-metal plasmonic absorber with an absorption bandwidth less than 8 nm and polarization insensitive absorptivity exceeding 99%. Unlike traditional Metal-Dielectric-Metal configurations, we demonstrate that the narrowband perfect absorption and field enhancement are ascribed to the vertical gap plasmonic mode in the deep subwavelength scale, which has a high quality factor of 120 and mode volume of about 10−4× (λres/n)3. Based on the coupled mode theory, we verify that the diluted field enhancement is proportional to the absorption and thus perfect absorption is critical to maximum field enhancement. In addition, the proposed perfect absorber can be operated as a refractive index sensor with a sensitivity of 885 nm/RIU and figure of merit as high as 110. It provides a new design strategy for narrow band perfect absorption and local field enhancement and has potential applications in biosensors, filters and nonlinear optics.