Metasurface with multi-sized structure for multi-band coherent perfect absorption
Metasurface with multi-sized structure for multi-band coherent perfect absorption
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DOI：
10.1364/oe.26.007066
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发表时间：
2018-03-19
期刊：
影响因子：
3.8
通讯作者：
Li, Ling
中科院分区：
文献类型：
--
作者：
Huang, Sha;Xie, Zhengwei;Li, Ling
我们证明了在红外频率下，可以通过一个超表面来实现多波段的相干完美吸收，在这个超表面中，四个尺寸的柱状金属斑块被一个单位电池中的介电层分开。在保持高吸光度的同时，吸收带宽比单带吸收提高了3倍。相干完全吸收与偏振无关，可以通过调谐两个相干入射光束的相位差在每个谐振频率上独立调制。此外，谐振频率对柱状贴片半径敏感，因此通过调节半径可以获得较宽的相干完美吸收频率范围。通过优化结构参数，在TE和TM两种偏振方向均实现了近乎完美的斜入射吸收。优化后的超表面可以用作斜入射的分束器。(C) 2018年美国光学学会根据OSA开放获取出版协议的条款
We demonstrate that multi-band coherent perfect absorption can be achieved at infrared frequencies by a metasurface in which four-sized columnar metal patches are separated by a dielectric layer in a unit cell. The absorption bandwidth is enhanced by three times compared with single-band absorption while high absorbance is maintained. The coherent perfect absorption is polarization-independent and can be independently modulated at each resonant frequency by tuning the phase difference of two coherent incident beams. Moreover, the resonant frequency is sensitive to the radius of the columnar patch, and thus a wide coherent perfect absorption frequency range can be obtained by adjusting the radius. Through optimizing the structural parameters, nearly perfect absorption at oblique incidence for both TE and TM polarizations are achieved. The optimized metasurface can be used as a beamsplitter at oblique incidence. (C) 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement