金属微纳结构中的等离激元模式激发时, 伴随着局域场的增强, 存在对光的吸收增强的现象。但是这种光学吸收增强依赖于模式共振, 因而吸收的带宽通常比较窄。项目提出了利用常规的镀膜工艺制备由金属颗粒-介质薄膜-金属薄膜构成的“类三明治”微纳结构, 详细研究了上层金属颗粒尺寸和中间介质层薄膜厚度对光吸收的影响, 优化制备工艺和微纳结构, 提出最佳结构参数, 实现对光的宽波段的近完美吸收。项目工艺快速简单, 成本低廉, 适合大批量以及大面积的样品制备。

Accompanied with the excitations of the plasmonic resonances, the local optical fields around the metallic micro/nano-structures could be enhanced, resulting in a great enhancement of the optical absorption. However, the enhancement of optical absorption depends on mode resonance, so the absorption bandwidth is usually narrow. A sandwich-like three-layered nanostructure could be fabricated using conventional coating technology is presented. The nanostructure is consist of a monolayer metallic nanoparticles and a metal film separated by a dielectric gap layer. The effects of the size of the metallic nanoparticles and the thickness of the dielectric gap layer on the optical absorption of the sandwich-like nanostructure are studied. It is demonstrated that a sandwich-like nanostructure with the optimal parameters is capable of near-completely absorbing light within a broad-band spectral range. The method is simple, cost-effective, and suitable for a massive, large-area production of sandwich-like near-perfect optical absorbers.