Comprehensive investigations of absorption enhancement by a period array of nano-grooves in gold substrate are provided. A simple Fabry–Perot model is presented to explore impact factors on absorption enhancement. The impacts of structural parameters on absorption enhancement for an array of nano-grooves are explored and discussed. Our calculations show that complete absorption (about 1) can be obtained with the groove depth fulfilling the Fabry–Perot resonance condition. The effect of groove width on absorption for a trapezoidal groove array is slightly different from that for a rectangular groove array, because of the impact of single-pass loss in the grooves. Surface plasmon resonance that can carry most of the energy away from grooves and propagate along the metal surface could lead to extremely low absorption for a period array of nano-grooves. Our discussions identify two key roles in absorption enhancement for a nano-groove array: the fundamental groove mode resonance and the generation of surface plasma polaritons. In addition, the analysis of absorption enhancement for an array of trapezoidal grooves can also provide a comprehensive contribution of Fabry–Perot resonance and electromagnetic interaction along the bevel edges of the trapezoidal grooves.

中文翻译：

---

通过金基体中的纳米凹槽的周期阵列增强吸收。

提供了对金基底中纳米槽的周期阵列的吸收增强的综合研究。提出了一个简单的Fabry-Perot模型来探索影响吸收增强的因素。探索和讨论了结构参数对纳米沟槽阵列吸收增强的影响。我们的计算表明，在满足Fabry-Perot共振条件的凹槽深度下，可以获得完全吸收（大约1）。梯形凹槽阵列的凹槽宽度对吸收的影响与矩形凹槽阵列的吸收稍有不同，这是因为凹槽中单程损耗的影响。可以将大部分能量带离凹槽并沿金属表面传播的表面等离振子共振可能会导致纳米槽的周期阵列的极低吸收。我们的讨论确定了纳米槽阵列在吸收增强中的两个关键作用：基本的槽模共振和表面等离子体极化子的产生。此外，对梯形凹槽阵列的吸收增强的分析还可以为梯形凹槽的斜边沿的法布里-珀罗共振和电磁相互作用提供全面的贡献。