基于氧化石墨烯的可调多焦点超透镜设计

Design of Adjustable Multi-Focus Metalens Based on Graphene Oxide

基于超表面设计的超透镜可以调制光的振幅、相位和偏振,并获得多种新颖的聚焦效果,近年来受到广泛关注。受制于材料调控与光场调制的局限,常见的超透镜多表现出静态单一的光场聚焦效果。本文基于氧化石墨烯材料可调制光学性质,采用时域有限差分法(finite difference time domain, FDTD),针对正交圆偏振设计超透镜,通过模拟材料相变产生的折射率变化,在焦点处表现出光强度可调能力,并表现出几何相位与传输相位共同影响的聚焦机制。同时,对超透镜进行多区域设计,在不同偏振状态光的入射下实现独立聚焦效果,为实现多焦点、可调超透镜功能器件的设计提供了重要依据。

The metalens designed based on the metasurface can modulate the amplitude, phase and polariza-tion of light and obtain a variety of novel focusing effects, which have received widespread con-cerned in recent years. Due to the limitation of the material regulation and light field modulation, common metalens often shows the static light field focusing ability. Based on the tunable optical properties of graphene oxide, the orthogonal circularly polarized independent focusing metalens is designed by using the finite-difference time-domain (FDTD) algorithm. By simulating the change of refractive index caused by material phase change, the focal point of the lens exhibits the ability to adjust the light intensity, and shows the focusing mechanism of the joint influence of geometric phase and transmission phase. At the same time, independent focusing effect is achieved under the incidence of light in different polarization states through the multi-region design of the metalens, providing an important basis for the design of multifocus, adjustable metalens functional devices.