基于复合涡旋光场的超快速旋转光束的产生机制和传输特性研究

The composite vortex fields have advantages of multi-orbit angle momentums, multiphase singularities and high power density. By making the composite vortex fields rotate on a period of a few picoseconds can add a new control parameter for beam control and application, which exhibits novel physical properties and unique advantages in laser material interaction, laser communication, particle manipulation and laser confinement fusion. However, up to now, there are a few literatures on how to obtain beam rotating on a period of a few picoseconds, and the exploration on applications of the ultrafast rotating beam is still in its fancy. In previous studies, we have obtained an ultrafast rotating beam by using coherent superposition of vortex beams and have successfully applied this technique to improve the irradiation uniformity. However, the generation mechanism, control and propagation characteristics of the rotate beam need to be further studied. In this project, we shall carry out investigation about the generation mechanism and propagation characteristics of the ultrafast rotating beam based on the previous studies. The whole project has three components: (1) put forward the generation mechanism and control technologies of the ultrafast rotating beam; (2) investigate the propagation, rotation and de-coherence characteristics of the ultrafast rotating beam in complicated propagation medium; (3) applications and experimental analysis of the ultrafast rotating beam. Collectively, we hope to promote the ultrafast rotating beam technique and lay a solid foundation for the development and application of beam control technologies and nonlinear effect mitigation methods.

复合涡旋光场具有多轨道角动量、多相位奇点和高功率密度等特点，而使复合涡旋光场以皮秒周期旋转可为光束的调控和应用新增一个参量，在激光与物质相互作用、激光通讯、粒子操控和激光核聚变等领域展现新颖的物理特性和独特的优势。但到目前为止，如何获得旋转周期为皮秒量级的光束的报道较少，其相关应用的研究还处在起步阶段。本课题组近期利用涡旋光束相干合成获得了皮秒旋转周期的光束，并成功将其应用于光束均匀化，但仍需对旋转光束的产生、调控及其传输特性进行深入研究。本研究拟在前期研究基础上开展基于复合涡旋光场的超快速旋转光束的产生机制和传输特性研究，包括：（1）超快速旋转光束的产生机制和调控机理研究；（2）复杂传输通道中超快速旋转光束的传输特性研究；（3）超快速旋转光束的应用及验证性实验研究，以为其在相关领域迫切需求的皮秒量级光束调控技术和非线性效应抑制手段等方面的应用奠定坚实的基础。

超快速旋转光束可为光束的调控和应用新增一个参量，展现新颖的物理特性和独特的优势，为激光与物质相互作用和激光核聚变等领域中迫切需求的皮秒量级光束调控和非线性效应抑制技术提供新手段和新途径，并为其涉及的新型物理效应的发掘和应用奠定坚实的基础。本项目执行期间发展了一系列空间模式丰富、调控自由度高的快速旋转光束及其调控技术，进而针对其在激光核聚变、光通讯等领域的应用开展研究。包括：（1）发展了一种新型偏振旋转矢量光场方案，并成功将其应用于激光等离子体不稳定性抑制，有望为激光核聚变的光场调控提供新的技术途径。（2）提出了一种新型相位自旋转光束，并将其成功应用于激光在复杂介质（大气、海水）的湍流和热晕效应抑制，有望为激光通信、强激光技术等领域的发展提供新的技术途径。（3）开展了紧聚焦条件下结构光束调控和相干合成研究，研究了紧聚焦条件下复合涡旋光的聚焦和合成特性，为发展基于结构光的新型旋转光束奠定基础。