Lyu Zijian, Fang Yiqi, Liu Yunquan
State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-Optoelectronics, School of Physics, <a href="https://ror.org/02v51f717">Peking University</a>, Beijing 100871, China.
Department of Physics, <a href="https://ror.org/0546hnb39">Universität Konstanz</a>, Konstanz 78464, Germany.
Phys Rev Lett. 2024 Sep 27;133(13):133801. doi: 10.1103/PhysRevLett.133.133801.
Toroidal vortex is a kind of novel and exotic structured light with potential applications in photonic topology and quantum information. Here, we present the study on high harmonic generation from the interaction of the intense toroidal vortices with atoms. We show that the spatial distribution of harmonic spectra reveal unique structures, which are kinds of high-order topological toroidal vortex because of the rotating of the driving fields with transverse orbital angular momentum. Then we show that, by synthesizing the toroidal vortices and optical vortices with longitudinal orbital angular momentum, it is able to generate the optical hopfions in the extreme ultraviolet range, which exhibit a completely different topological property compared with both the driving fields. Harnessing the spin angular momentum selection rules, we further show that one can control the topological texture and channel each harmonic into a single mode of controllable Hopf invariant.
环形涡旋是一种新型的奇特结构光，在光子拓扑和量子信息领域具有潜在应用。在此，我们展示了关于强环形涡旋与原子相互作用产生高次谐波的研究。我们表明，谐波谱的空间分布揭示了独特的结构，由于驱动场具有横向轨道角动量的旋转，这些结构属于高阶拓扑环形涡旋。然后我们表明，通过将环形涡旋与具有纵向轨道角动量的光学涡旋合成，能够在极紫外范围内产生光学霍普夫离子，与两个驱动场相比，其展现出完全不同的拓扑性质。利用自旋角动量选择规则，我们进一步表明，人们可以控制拓扑纹理并将每个谐波引导到具有可控霍普夫不变量的单一模式中。
