Cao Wei, Gao Jie, Yang Xiaodong
Opt Express. 2020 Jul 6;28(14):20051-20061. doi: 10.1364/OE.391873.
Metamaterials are artificially engineered structures that have unique properties not usually found in natural materials, such as negative refractive index. Conventional interferometry or ellipsometry is generally used for characterizing the optical properties of metamaterials. Here, we report an alternative optical vortex based interferometric approach for the characterization of the effective parameters of optical metamaterials by directly measuring the transmission and reflection phase shifts from metamaterials according to the rotation of vortex spiral interference pattern. The fishnet metamaterials possessing positive, zero and negative refractive indices are characterized with the vortex based interferometry to precisely determine the complex values of effective permittivity, permeability, and refractive index. Our results will pave the way for the advancement of new spectroscopic and interferometric techniques to characterize optical metamaterials, metasurfaces, and nanostructured thin films in general.
超材料是人工设计的结构，具有天然材料通常不具备的独特特性，如负折射率。传统的干涉测量法或椭偏测量法通常用于表征超材料的光学特性。在此，我们报告了一种基于光学涡旋的替代干涉测量方法，用于通过根据涡旋螺旋干涉图案的旋转直接测量超材料的透射和反射相移来表征光学超材料的有效参数。采用基于涡旋的干涉测量法对具有正、零和负折射率的渔网超材料进行了表征，以精确确定有效介电常数、磁导率和折射率的复数值。我们的结果将为开发用于表征光学超材料、超表面和一般纳米结构薄膜的新光谱和干涉测量技术铺平道路。
