基于层间模式耦合和杂化的理想电磁透明及高效涡旋波束编码研究

Vortex beams are characterized by a helical wavefront, carrying quantized orbital angular momentum. And those beams with different quantum numbers are orthogonal to each other. These features provide a way of spatial modulation for communications, which greatly enhances the channel capacity of microwaves. Metasurfaces are two-dimensional artificial materials, which allow full control of the phase, polarization, amplitude and absorption of incident waves within an optically thin thickness. It can be utilized for wavefront engineering, which facilitates the generation and manipulation of vortex beams. How to improve the efficiency has become the investigation hotspot of beam steering with metasurfaces. In this project, we will study the mutual coupling and hybridization of local resonances in multilayer metasurfaces, to reveal the relation between electromagnetic transparency and resonance modes. By improving the efficiency of neighboring interaction, acquire the phase modulation method with transmittance greater than 95%, to achieve efficient vortex beam generation. By introducing active elements to the multilayer structures, realize the dynamic control of vortex beams, to break through the communication difficulties. This project is well supported by the feasible scheme and abundant reserve in theory and experiment condition, and will be accomplished successfully with the grant.

涡旋波束波前呈螺旋状，携带量子化的轨道角动量，具有不同量子数的涡旋波束彼此正交。涡旋波束给无线通信提供了一种空间调制手段，可以大幅提升微波通信的信道容量。超表面具有自由调控电磁波相位、极化、振幅、吸收的能力，利用超表面对波束的波阵面进行相位裁剪可用于实现涡旋波束调控，如何提高超表面相位调控效率是波束调控的研究热点。本项目拟围绕超表面界面模式的层间耦合和杂化开展研究，揭示电磁透明与界面模式层间耦合物理规律，通过设计层叠结构的近邻耦合效率，获得透过率大于95%的相位调控方法，从而实现高效率的涡旋波束产生。通过在层叠超表面的加载可调控集总参数元件，实现涡旋波束动态调控和编码方法，突破涡旋波束通信困难。本项目初步证明原理正确，技术路线可行，基础研究方面理论和实验储备充分，可以支撑项目的开展。如果获得资助将可以圆满完成本申请课题。

超表面具有自由调控电磁波相位、极化、振幅、吸收的能力，利用超表面对波束的波阵面进行相位裁剪可用于实现波束调控，如何提高超表面相位调控效率是波束调控的研究热点。本课题提出基于层间模式耦合和杂化的理想电磁透明及高效涡旋波束编码研究，按计划开展研究，完成了预设的研究目标、所有研究内容，具体如下：1）针对光栅结构和光学薄膜中节瘤结构开展耦合效应的理论研究，完成了耦合效应物理机制的解释，通过模拟计算和实验验证了耦合效应对光栅衍射效率及节瘤散射特性分析的正确性以及其产生的影响。2）基于层间模式耦合和杂化的理念，设计了超表面结构，实现了高效的相位调控，包括不同应用场景下的高效率聚焦、电磁动态透明、电磁极化动态调控、电磁吸收动态调控；3）针对现有的集成涡束发射器的OAM模式数量与发射器尺寸之间存在约束关系的问题，提出通过改变波导高度来实现高耦合效率和高耦合纯度的相位匹配方法，打破了发射器尺寸与发射模式数目的制约关系，实现了小尺寸与多模式涡旋光发射器设计。.在课题的资助下，项目负责人在Advanced Optical Materials、Nanoscale Advances、Optics Express、Optics Letters、Micromachines、Frontiers in Physics等杂志上发表论文10篇，并进行了标注，申请专利4项并均获得授权，培养毕业硕士1人，协助培养毕业博士硕士4人，承担了6位本科应届毕业生论文指导工作，培养在读博士硕士研究生3人。