五分钟光学: 复旦大学周磊教授：超构表面如何实现真正的应用？

超构表面是一种平面型的人工材料，可以实现对电磁波的任意调控，例如偏折、偏振等。这种材料有两个特点：1）超薄；2）是一种甚至可以和物体“共形”的平面结构。因此，它的应用非常广泛。不同于传统光学器件利用光在材料里的相位积累调控波前，超构表面通过设计平面型人工微结构，利用其共振效应进行调控。当把不同的人工微结构拼接成超构表面时，利用界面的相位突变形成不同点的次波源，从而调控电磁波。超构表面经过八九年的发展，下一步将何去何从？周磊教授认为超构表面要真正实现应用，必须解决动态可调、效率、角域和频域色散问题，以及如何使用超构表面实现对电磁波的近场和远场的自由操控问题。

Metasurface is a planar artificial material that can achieve arbitrary control of electromagnetic waves, such as deflection, polarization, etc. This material has two characteristics: 1) ultrathin; 2) it is a planar structure that can even be conformal to objects. Therefore, its applications are very extensive. Unlike traditional optical devices that use the phase accumulation of light in the material to control the wavefront, metasurfaces use the resonant effect of designed planar artificial microstructures for control. When different artificial microstructures are assembled into a metasurface, the subwave source of different points is formed by using the phase jump of the interface, thereby controlling the electromagnetic wave. After eight or nine years of development, where will metasurfaces go next? Professor Lei Zhou believes that to truly realize the application of metasurfaces, it is necessary to solve the problems of dynamic adjustability, efficiency, angular and frequency-domain dispersion, and how to use metasurfaces to realize free manipulation of near-field and far-field electromagnetic waves.