A unified Brewster effect condition is proposed as a guideline for the design of the reflectionless lens. Previously, most of the investigations on the Brewster effect are limited for the homogeneous isotropic medium and the condition is sensitive to the polarization states. Here, it is predicted both theoretically and numerically that an arbitrarily polarized electromagnetic wave can perfectly refract through an anisotropic plate. In particular, both TE- and TM-polarized incident waves can have an identical Brewster angle with total transmission at either normal or oblique incidence by adjusting the material anisotropy. As a proof of concept, we employ this unified theory into the design of a 2-D reflectionless lens with a simplified restriction condition. It is demonstrated that perfect wavefront shaping with no fundamental limits on its efficiency is obtained with the proposed topology. To illustrate practically the concept of Brewster lens, a three-layer cascaded lens is fabricated and measured with a thickness of $0.1\lambda $ and an aperture efficiency of 94.3%. A remarkable 10.3 dB gain increasement is obtained compared with its counterparts.

中文翻译：

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具有完美波折射的布鲁斯特透镜

提出了统一的布鲁斯特效应条件作为无反射透镜设计的指导原则。以前，大多数关于布鲁斯特效应的研究仅限于均匀各向同性介质，并且条件对偏振态敏感。在这里，理论上和数值上都预测任意极化的电磁波可以完美地折射通过各向异性板。特别是，通过调整材料的各向异性，TE 和 TM 偏振入射波都可以具有相同的布鲁斯特角，并且在垂直入射或斜入射时具有总透射率。作为概念证明，我们将这一统一理论应用到具有简化限制条件的二维无反射透镜的设计中。结果表明，使用所提出的拓扑结构可以获得对其效率没有基本限制的完美波前整形。为了实际说明布鲁斯特透镜的概念，制造并测量了三层级联透镜，厚度为 0.1 λ ，孔径效率为 94.3%。与同类产品相比，获得了显着的 10.3 dB 增益增加。