Metal-free plasmonic refractory core-shell nanowires for tunable all-dielectric broadband perfect absorbers.
Metal-free plasmonic refractory core-shell nanowires for tunable all-dielectric broadband perfect absorbers.
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DOI：
10.1364/oe.405625
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发表时间：
2020-11
期刊：
影响因子：
3.8
通讯作者：
Houjiao Zhang;Zheng-qi Liu;Haozong Zhong;Guiqiang Liu;Xiaoshan Liu;Junqiao Wang
中科院分区：
文献类型：
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作者：
Houjiao Zhang;Zheng-qi Liu;Haozong Zhong;Guiqiang Liu;Xiaoshan Liu;Junqiao Wang
在这项工作中，我们数值模拟了一种新的全介质宽带光学理想吸收体的简易策略。单层耐火氧化钛和氮化物（TiN/TiO 2）核-壳纳米线阵列用于在不透明TiN衬底上形成光栅。在相邻的波长范围内观察到多个共振吸收带，因此导致形成从可见光到红外区的超宽带吸收窗口。最大吸收率达95.6%，在0.5-1.8 μm范围内的平均吸收效率达85.4%。此外，通过调节偏振态，可以在保持高吸收效率的同时，对吸收带宽进行可行的调节。此外，观察到的吸收窗口是高度可调的波长范围内，示出了一个接近线性关系的壳的指数。这些特性不仅证实了宽带理想吸收的实现，而且为人工调控吸收特性提供了可行的方法，在太阳能收集、光探测、热发电等无金属等离子体光电器件及其相关的生物医学技术中具有广泛的应用前景。
In this work, we numerically demonstrate a new facile strategy for all-dielectric broadband optical perfect absorbers. A monolayer refractory titanium oxide and nitride (TiN/TiO2) core-shell nanowires array is used to form the grating on the opaque TiN substrate. Multiple resonant absorption bands are observed in the adjacent wavelength range, which therefore leads to the formation of an ultra-broadband absorption window from the visible to the infrared regime. The maximal absorption reaches 95.6% and the average absorption efficiency in the whole range (0.5-1.8 µm) is up to 85.4%. Moreover, the absorption bandwidth can be feasibly adjusted while the absorption efficiency can be still maintained in a high level via tuning the polarization state. Furthermore, the absorption window is observed to be highly adjustable in the wavelength range, showing a nearly linear relationship to the shell's index. These features not only confirm the achievement of the broadband perfect absorption but also introduce feasible ways to artificially manipulate the absorption properties, which will hold wide applications in metal-free plasmonic optoelectronic devices such as the solar harvesting, photo-detection, and thermal generation and its related bio-medical techniques.