Spatiotemporal optical vortex (STOV) wavepacket carrying transverse photonic orbital angular momentum (OAM) has been extensively studied in the past few years. In this Letter, we propose and study a novel STOV wavepacket with multiple phase singularities embedded in different space–time domains using analytical and numerical approaches. By tuning different parameters used for designing the wavepacket, it is possible to engineer both the magnitude and orientation of the photonic OAM in space–time. The vectorially controllable OAM will pave new avenues and facilitate applications such as novel optical communication, studying complicated quantum systems, and spin-and-OAM interactions.

Spatiotemporal optical vortex (STOV) pulses can carry transverse orbital angular momentum (OAM) that is perpendicular to the direction of pulse propagation. For a STOV pulse, its spatiotemporal profile can be significantly distorted due to unbalanced dispersive and diffractive phases. This may limit its use in many research applications, where a long interaction length and a tight confinement of the pulse are needed. The first demonstration of STOV pulse propagation through a few-mode optical fiber is presented. Both numerical and experimental analysis on the propagation of STOV pulse through a commercially available SMF-28 standard telecommunication fiber is performed. The spatiotemporal phase feature of the pulse can be well kept after the pulse propagates a few-meter length through the fiber even with bending. Further propagation of the pulse will result in a breakup of its spatiotemporal spiral phase structure due to an excessive amount of modal group delay dispersion. The stable and robust transmission of transverse photonic OAM through optical fiber may open new opportunities for transverse photonic OAM studies in telecommunications, OAM lasers, and nonlinear fiber-optical research.

为了产生轴向双焦点中空环形光斑，基于矢量衍射积分得出的环带半径公式，设计产生了呈环带分布的轴向双焦点的螺旋相位，并研究了这种螺旋相位在高数值孔径物镜聚焦区域的光斑特性。首先，给出了线偏振以及圆偏振的涡旋光束在高数值孔径物镜聚焦条件下的积分表达式。然后，利用此积分表达式数值模拟了线偏振光与圆偏振光在不同轴向偏移距离及螺旋拓扑荷值时的聚焦光场分布。最后，将轴向双焦点螺旋相位加载到纯相位空间光调制器上，分别对圆偏振光与线偏振光入射进行实验研究。线偏振光入射时，实验产生了拓扑荷为1且轴向距离为±10 μm、±15 μm的双聚焦环形光斑；圆偏振光入射时，产生了轴向距离为±20 μm且拓扑荷为1到4时的双聚焦环形光斑。数值模拟与实验结果表明：圆偏振光与线偏振光经此螺旋相位调制后，在紧聚焦区域可产生轴向距离与暗斑大小可调的中空环形双焦点；圆偏振光较线偏振光产生的空心光斑光强分布更均匀，呈圆对称分布。此轴向双焦点螺旋相位有望在光学微操控、双光束超分辨纳米光刻以及STED显微成像方面获得一定的应用。

结合光束塑形技术、坐标变换技术、傅里叶相移定理，成功产生了霍曼转移结构光束，其具备相位梯度，从而拥有在微观世界中输运粒子的能力，并且大小、结构、相位梯度，均可任意调控，在应用中可依据实际需求对光束进行相应的调整。搭建光镊实验光路，并使用霍曼转移结构光束对聚苯乙烯粒子进行了操控，其实验结果与理论相符，可以使粒子完美的沿着轨道进行输运。该研究在光学微操纵特别是粒子的变轨运输领域具有重要的意义。

The cylindrical vector beam (CVB) has been extensively studied in recent years, but detection of CVBs with on-chip photonic devices is a challenge. Here, we propose and theoretically study a chiral plasmonic lens structure for CVB detection. The structure illuminated by a CVB can generate single plasmonic focus, whose focal position depends on the incident angle and the polarization order of CVB. Thus, the incident CVB can be detected according to the focal position and incident angle and with a coupling waveguide to avoid the imaging of the whole plasmonic field. It shows great potential in applications including CVB-multiplexing integrated communication systems.

涡旋光束因为携带轨道角动量，在光通信、粒子操纵及量子信息等领域都具有重要的应用前景。目前有很多方法可用于产生涡旋光束，如利用螺旋相位板、模式转换、空间光调制器等。然而，传统的方法需要搭建体积相对较大的光学系统，限制了其在集成光学等领域中的应用。不同于传统方法中通过传输效应来获得相位变化，超表面可以通过纳米结构使入射光产生相位突变，在纳米尺度上独立控制动态或几何相位以产生涡旋。超表面具有强大光控制能力的同时，还具有体积小、易于集成等特点，因此成为了产生涡旋光的理想方法。文中在介绍产生涡旋光束基本原理的基础上，回顾了近年来利用超表面产生涡旋光束的研究进展。首先介绍了利用动力学相位、Pancharatnam-Berry (P-B)相位以及混合相位产生光学涡旋的方法。随后，对利用全息与编码超表面产生涡旋及通过多路复用产生多个涡旋等不同方法进行了综述。最后，对基于超表面产生涡旋的一些亟待解决的问题和应用前景作了简单总结与讨论。

涡旋光在光通信、量子纠缠、新的非线性光学效应、微纳机械加工、超分辨成像和光镊等领域具有重要的应用价值。涡旋光应用的前提条件是高质量涡旋光束的产生，将缺陷镜技术和固体激光谐振腔技术结合起来研究，对直接产生高光束质量、高稳定性和大拓扑荷数（高阶）的涡旋激光具有明显的优势。当前，该项技术多是用在简单的两镜线性腔中，且以连续波涡旋激光为主。文中使用紫外皮秒脉冲激光器制备了点缺陷镜，并采用LD端面泵浦Nd:YVO₄晶体作为激光实验平台，构造了V型激光谐振腔，首次实现了复杂谐振腔内直接产生高阶涡旋激光输出。当吸收功率为11.46 W时，获得了最高输出功率为2.69 W的三阶涡旋激光，斜效率达到23.6%；进一步调节谐振腔及点缺陷尺寸，最高获得了13阶涡旋激光输出。该研究表明缺陷镜技术也可以用于复杂结构激光谐振腔，直接产生高阶涡旋激光，从而为其他运行模式（如调Q和锁模）的高阶涡旋激光研究提供了一定的依据。

In free-space or in optical fibers, orbital angular momentum (OAM) multiplexing for information transmission has been greatly developed. The light sources used were well coherent communication bands, and the fibers used were customized. Here, we use an 810 nm femtosecond laser to generate optical vortices carrying OAM and then feed them into two kinds of commercial step-index few-mode fibers to explore the transmission characteristics of OAM modes. We also propose a method without multiple-input multiple-output digital signal processing to identify the input OAMs. It is of great guiding significance for high-dimensional quantum information experiments via the OAMs as a degree of freedom, using the light generated by the spontaneous parametric down-conversion as the source and the commercial fibers for information transmission.