Qian Qinyu, Yan Ying, Wang Chinhua
Opt Lett. 2018 Mar 15;43(6):1231-1234. doi: 10.1364/OL.43.001231.
We report on a monolithic, all-metallic, and flexible metasurface perfect absorber [black nickel (Ni)] based on coupled Mie resonances originated from vertically stepped Ni nanopillars homoepitaxially grown on an Ni substrate. Coupled Mie resonances are generated from Ni nanopillars with different sizes such that Mie resonances of the stepped two sets of Ni nanopillars occur complementarily at different wavelengths to realize polarization-independent broadband absorption over the entire visible wavelength band (400-760 nm) within an ultra-thin surface layer of only 162 nm thick in total. Two-step double-beam interference lithography and electroplating are utilized to fabricate the proposed monolithic metasurface that can be arbitrarily bent and pressed. A black nickel metasurface is experimentally demonstrated in which an average polarization-independent absorption of 0.972 (0.961, experiment) in the entire visible band is achieved and remains 0.838 (0.815, experiment) when the incident angle increases to 70°.
我们报道了一种基于耦合米氏共振的单片式、全金属且柔性的超表面完美吸收体[黑镍（Ni）]，该耦合米氏共振源于在镍衬底上同质外延生长的垂直阶梯状镍纳米柱。不同尺寸的镍纳米柱产生耦合米氏共振，使得两组阶梯状镍纳米柱的米氏共振在不同波长下互补发生，从而在仅162nm厚的超薄表面层内实现整个可见光波段（400 - 760nm）的偏振无关宽带吸收。利用两步双光束干涉光刻和电镀工艺制备了所提出的可任意弯曲和按压的单片超表面。实验展示了一种黑镍超表面，在整个可见光波段实现了平均偏振无关吸收率为0.972（实验值为0.961），当入射角增加到70°时，吸收率仍保持在0.838（实验值为0.815）。
