Broadband Control of Group Delay Using the Brewster Effect in Metafilms
Broadband Control of Group Delay Using the Brewster Effect in Metafilms
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DOI：
10.1103/physrevapplied.18.014029
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发表时间：
2022-07
影响因子：
4.6
通讯作者：
Y. Tamayama;Hiromu Yamamoto
中科院分区：
文献类型：
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作者：
Y. Tamayama;Hiromu Yamamoto
我们提出并验证了一种在有限厚度的单层超材料（这里称为元膜）中利用布鲁斯特效应控制电磁波群延迟在宽频率范围内的频率依赖性的方法。当元膜的反射率与入射频率无关时，在其共振频率附近，群延迟可以很大，而透射率与入射频率无关。此外，当多个无反射元膜堆叠在一起时，总群延迟应表示为单个群延迟的总和。在这项研究中，我们通过排列元原子来实现无反射的元膜，使布鲁斯特效应与入射频率无关。通过数值模拟和实验研究了由不同谐振频率的无反射元膜组成的三层超材料的透射率和群延迟与频率的关系，发现该超材料的总透射率和群延迟分别与组成元膜的透射率和群延迟之和的乘积一致。
We propose and verify a method for controlling the frequency dependence of the group delay of electromagnetic waves over a broad frequency range using the Brewster effect in single-layer metamaterials with finite thickness, here referred to as metafilms. When the metafilm’s reflectance vanishes regardless of the incident frequency, the group delay can be large near its resonance frequency while maintaining the transmittance close to unity regardless of the incident frequency. Furthermore, when several reflectionless metafilms are stacked together, the total group delay should be given as the sum of the individual group delays. In this study, we realize reflectionless metafilms by arranging the meta-atoms so that the Brewster effect occurs regardless of the incident frequency. We evaluate in numerical simulations and experiments the frequency dependence of the transmittance and of the group delay of a three-layer metamaterial composed of reflectionless metafilms with different resonance frequencies, and find that the total transmittance and group delay of this metamaterial agree respectively with the product of the transmittances and the sum of the group delays of the constituent metafilms.