近日，澳大利亚墨尔本大学Sejeong Kim团队实现了范德华材料中的自旋轨道耦合用于光学涡旋的产生。相关论文于2025年8月18日发表在《光：科学与应用》杂志上。

光学涡旋光束在光学操作、相衬显微镜、光通信和量子光子学等多种应用中引起了广泛的关注。为了将涡旋发生器用于集成光子学，研究组开发了以叉形光栅、超表面和集成微梳为主题的超紧凑涡旋发生器。然而，这些设备依赖于昂贵、耗时的纳米制造，并且由于制造误差而受到低信噪比的限制。作为一种替代机动，自旋-轨道耦合作为一种通过转换自旋角动量（SAM）来获得涡旋光束的方法已经出现。

研究组演示了以范德华（vdW）材料为主题的光学涡旋光束的创建。vdW材料显著的高双折射特性使得即使是亚波长厚度的材料也能产生光学涡旋光束。研究组使用了8μm厚的六方氮化硼（hBN）晶体用于产生携带±2拓扑电荷的光学涡流。他们还介绍了在320纳米厚度的MoS₂晶体，转换效率为0.09。该研究为光学涡旋发生器的无制造和超紧凑化铺平了道路，可应用于集成光子学和大型涡旋发生器阵列。

附：英文原文

Title: Spin-orbit coupling in van der Waals materials for optical vortex generation

Author: Jo, Jaegang, Byun, Sujeong, Bae, Munseong, Wang, Jianwei, Chung, Haejun, Kim, Sejeong

Issue&Volume: 2025-08-18

Abstract: An optical vortex beam has attracted significant attention across diverse applications, including optical manipulation, phase-contrast microscopy, optical communication, and quantum photonics. To utilize vortex generators for integrated photonics, researchers have developed ultra-compact vortex generators using fork gratings, metasurfaces, and integrated microcombs. However, those devices depend on costly, time-consuming nanofabrication and are constrained by the low signal-to-noise ratio due to the fabrication error. As an alternative maneuver, spin-orbit coupling has emerged as a method to obtain the vortex beam by converting spin angular momentum (SAM) without nanostructures. Here, we demonstrate the creation of an optical vortex beam using van der Waals (vdW) materials. The significantly high birefringence of vdW materials allows the generation of optical vortex beams, even with materials of sub-wavelength thickness. In this work, we utilize an 8μm-thick hexagonal boron nitride (hBN) crystal for the creation of optical vortices carrying topological charges of ±2. We also present the generation of an optical vortex beam in a 320nm-thick MoS2 crystal with a conversion efficiency of 0.09. This study paves the way for fabrication-less and ultra-compact optical vortex generators, which can be applied for integrated photonics and large-scale vortex generator arrays.

DOI: 10.1038/s41377-025-01926-7

Source: https://www.nature.com/articles/s41377-025-01926-7