Padilla Willie J, Deng Yang, Khatib Omar, Tarokh Vahid
Pratt School of Engineering, Duke University, Durham, NC, 27705, USA.
Nanophotonics. 2024 Mar 8;13(9):1623-1629. doi: 10.1515/nanoph-2023-0920. eCollection 2024 Apr.
Past work has considered the analytic properties of the reflection coefficient for a metal-backed slab. The primary result established a fundamental relationship for the minimal layer thickness to bandwidth ratio achievable for an absorber. There has yet to be establishment of a similar relationship for non-metal-backed layers, and here we present the universal result based on the Kramers-Kronig relations. Our theory is validated with transfer matrix calculations of homogeneous materials, and full-wave numerical simulations of electromagnetic metamaterials. Our results place more general fundamental limits on absorbers and thus will be important for both fundamental and applied studies.
过去的工作已经考虑了金属背衬平板反射系数的解析特性。主要结果建立了吸收体可实现的最小层厚度与带宽比之间的基本关系。对于非金属背衬层，尚未建立类似的关系，在此我们基于克莱默斯－克勒尼希关系给出通用结果。我们的理论通过均匀材料的传输矩阵计算以及电磁超材料的全波数值模拟得到验证。我们的结果为吸收体设定了更普遍的基本限制，因此对于基础研究和应用研究都将具有重要意义。
