含超薄膜的层状吸收器完全吸收时材料优化选择

Selection of Materials for Perfect Absorption in Layered Absorbers with Ultrathin Films

含超薄膜结构的层状吸收器不仅设计加工结构十分简单,而且保证了优异的吸收性能,因而获得了越来越多的关注。层状结构实现完全吸收的机理,可以归结为吸收器在入射界面处导纳与入射空间导纳完全匹配。根据导纳分析理论,本文发展了一种可直接计算材料最优光学常数的方法,用于指导层状吸收器的材料优化选择。在不同的吸收基底上实现完全吸收,研究发现镀层薄膜的复折射率实部和虚部满足近似的线性关系,这对层状薄膜吸收器材料选择提供了必要的选择依据。根据导纳轨迹规律,仅借助导纳轨迹图,可以快速确定吸收材料的优化光学常数范围,因此对于估计和快速设计有着良好的参考价值。

Layered absorbers with ultrathin films are not only easy to design and manufacture, but also have good performance, which have attracted increasing attention. The mechanism of perfect absorption in layered structures can be attributed to the admittance matching between the absorber interface and the incident medium. Based on admittance analysis, the method of directly calculating optimal optical constants of materials is proposed, which can guide the selection of materials in layered absorbers. It is found that optimized materials have a near linear relationship between the real part and the imaginary part of optical constants for various substrates in absorbers. Considering the characteristic of admittance loci, admittance loci diagrams can be employed to fast narrow the region of optimal optical constants, which is helpful for quick engineering designs.