Near-perfect absorption throughout the visible using ultra-thin metal films on index-near-zero substrates [Invited]
Near-perfect absorption throughout the visible using ultra-thin metal films on index-near-zero substrates [Invited]
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DOI：
10.1364/ome.9.000330
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发表时间：
2019-01-01
影响因子：
2.8
通讯作者：
Monday, Jeremy N.
中科院分区：
文献类型：
--
作者：
Krayer, Lisa J.;Kim, Jongbum;Monday, Jeremy N.
金属具有高反射性，因此通常被忽视为有效的吸收体。然而，超薄金属膜中的亚波长法布里-珀罗共振已被用于实现70%以上的吸收，接近使用传统基板的完美吸收。在这里，我们采取了不同的方法，并表明，近完美的吸收是可以实现的，提供超薄金属沉积在折射率接近零（INZ）的基板。金属-INZ界面处的光学对比度增强了非平凡反射，导致多次反射后的相消干涉。在这篇手稿中，我们提出了超薄金属薄膜的设计考虑INZ基板上获得近乎完美的吸收整个可见光谱和近红外（NTR）。我们发现，通常用于等离子体和热载流子器件的金属，如Au和Ag，可以获得近紫外和可见光波长的近乎完美的吸收，而金属如Pd和Pt是整个近紫外到近红外光谱的有效吸收体。(C)2018年美国光学学会根据OSA开放获取出版协议的条款
Metals are highly reflective and therefore commonly overlooked as efficient absorbers. However, a subwavelength Fabry-Perot-like resonance in ultra-thin metal films has been used to achieve absorption above 70%, approaching perfect absorption using traditional substrates. Here we take a different approach and show that near-perfect absorption is achievable provided that the ultra-thin metals am deposited on an index near zero (INZ) substrate. The optical contrast at the metal-INZ interface enhances the non-trivial reflections leading to destructive interference after multiple reflections. In this manuscript, we present design considerations for ultra-thin metal films on INZ substrates to obtain near-perfect absorption throughout the visible spectrum and into the near-infrared (NTR). We find that metals commonly used for plasmonics and hot carrier devices, such as Au and Ag, can obtain near-perfect absorption for near-ultraviolet and visible wavelengths, while metals such as Pd and Pt are efficient absorbers throughout the near-ultraviolet to near-infrared spectrum. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement