Zhang Binglei, Liu Yang, Luo Yi, Kusmartsev Feodor V, Kusmartseva Anna
Micro/Nano Fabrication Laboratory, Microsystem and THz Research Center, Chengdu 610200, China.
Physics Department, Loughborough University, Loughborough LE11 3TU, UK.
Materials (Basel). 2020 Nov 28;13(23):5417. doi: 10.3390/ma13235417.
The terahertz (THz) frequency range is incredibly important as it covers electromagnetic emissions typical for biological and molecular processes. All molecules emit THz waves in a unique fingerprint pattern, although the intensity of such signals is usually too weak to be detected. To address the efficiency gap in existing THz devices it is extremely important to create surfaces with perfect anti-reflection properties. Although metals are absolutely reflective, here we show both theoretically and experimentally that by constructing meta-surfaces made of a superposition of ultra-thin metallic nano-films (a couple of nanometres thick) and oxide layers a unique property of perfect transmission and impedance matching may be realised. The perfect transmission rates can be as high as 100% and it may be achieved in both optical and THz regimes. The predicted effect has been observed for numerous meta-surfaces of different compositions. The effect found here is expected to impact the renewable energies sectors, optoelectronic and telecommunication industries, accelerating the arrival of the sensors for the new 6G-technology. The phenomenon is highly relevant to all scientific fields where minimising electromagnetic losses through reflection is important.
太赫兹（THz）频段极其重要，因为它涵盖了生物和分子过程中典型的电磁辐射。所有分子都会以独特的指纹图谱模式发射太赫兹波，尽管此类信号的强度通常太弱而无法检测到。为了解决现有太赫兹设备中的效率差距，制造具有完美抗反射特性的表面极为重要。尽管金属具有绝对的反射性，但我们在此从理论和实验两方面表明，通过构建由超薄金属纳米膜（几纳米厚）和氧化层叠加而成的超表面，可以实现完美传输和阻抗匹配的独特特性。完美传输率可高达100%，并且在光学和太赫兹频段均可实现。对于许多不同成分的超表面都观察到了预测的效果。此处发现的这种效应预计将对可再生能源领域、光电子和电信行业产生影响，加速新型6G技术传感器的问世。该现象与所有通过最小化反射电磁损耗至关重要的科学领域都高度相关。
