矢量光场携带的新型轨道角动量的设计、生成与研究

The photon orbital angular momentum (OAM), as a new fundamental controlling degree of freedom, has been exploited in a variety of realms. However, traditional OAM carried by vortex optical field has its limitations, such as the method of vortex phase manipulation lacks variety, the instability of propagation of fractional OAM and azimuthally non-uniform OAM, and so on. In order to solve these problems, there occur some researches about vector optical fields with space-variant polarization distribution carrying OAM in recent years. However, these researches just get started, which needs deeper study in manipulation method, the variety of OAM, properties and applications, etc. In this project, we will use the method of amplitude, phase and polarization manipulation, theoretically design and experimentally generate several kinds of new OAM carried by vector optical fields, and describe and illustrate these OAM by geometric phase. Combined with the model of photon angular momentum, we will further study the properties and applications of these new OAM, including propagation and focusing, spin-orbital angular momentum coupling and conversion, optical micro-manipulation and so on. This project studies the intersection of amplitude manipulation, phase manipulation (vortex optical field) and polarization manipulation (vector optical field), which can enrich the family of OAM, and provides new ideas for further studying and applying photon OAM.

作为一个新的光学自由度，光子轨道角动量已经被广泛的应用于众多领域。然而，传统涡旋光场携带的轨道角动量具有一定的局限性，例如：螺旋位相调控的方式单一以及分数阶和旋向非均匀的轨道角动量均无法稳定传播等。为了解决这些问题，近几年陆续出现了一些关于偏振态空间变化的矢量光场携带轨道角动量的研究。但是，这方面的研究才刚刚起步，在调控手段、角动量种类、性质与应用等方面有待深入展开。本项目拟采用振幅、位相和偏振联合调控的方式，理论设计和实验生成多种矢量光场携带的新型轨道角动量，用几何位相描述和解释这些轨道角动量，并结合新的光子角动量模型，进一步研究这些轨道角动量的性质和应用，包括传播与聚焦、自旋-轨道角动量的耦合与转化、光学微操纵等。本项目属于光场调控领域中振幅调控、位相调控（涡旋光场）与偏振调控（矢量光场）的研究交叉点，可以丰富轨道角动量的种类，进而为光子轨道角动量的深入研究和应用提供新的思路。

近年来，偏振态空间变化的矢量光场携带的轨道角动量引起了广泛的关注，极大拓展了光学轨道角动量的研究范围。本项目围绕矢量光场携带的光学轨道角动量展开，研究矢量光场和轨道角动量的相关性质和应用，具体研究内容和成果包括：（a）采用振幅、相位和偏振联合调控的方式，设计并调控了矢量光场携带的新型轨道角动量，包括旋向变化的可调谐光学轨道角动量和杂化偏振矢量光场携带的径向变化的轨道角动量等，探索了其传播和聚焦过程中的新颖光学效应；（b）提出了矢量光场紧聚焦的对称性分析理论和广义庞加莱球群模型，用于描述和设计矢量光场和光学角动量；（c）提出了万花筒矢量光场、双极杂化矢量光场、多奇点矢量光场和全庞加莱球矢量光场等新型矢量光场，研究了其光学角动量的变化规律并揭示了其中的物理机理；（d）提出了椭圆杂化矢量光场、抛物杂化矢量光场、双曲杂化矢量光场和双拼接矢量光场等其他新型矢量光场，研究了其焦移性质、超长焦深和阵列衍射等性质，有望应用于光学微操纵和微加工等领域。在本项目的资助下，共发表研究论文11篇（项目负责人为其中10篇论文的第一作者或通讯作者），申请国家发明专利1项。