晶体工程范德华材料中非线性结构光的全光开关
All-optical switching of nonlinear structured light in crystal-engineered van der Waals materials
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中文总结 AI 辅助
该研究利用人工3R-MoS₂晶体实现亚光周期精度的全光开关，可切换不同拓扑电荷的非线性结构光，为集成光子技术提供新型纳米光子源。
中文摘要 AI 辅助
光的轨道角动量（OAM）是一种离散且无界的自由度，为模式复用通信和高维量子光子学提供支撑。然而，动态OAM控制仍依赖于庞大的自由空间光学器件或级联架构，这类架构将开关功能与波前整形分离，阻碍了纳米级集成。本研究采用菱面体堆叠（3R）MoS₂制备人工范德华晶体，通过局部晶体取向的空间调控，将非线性几何相位 imprint 到二次谐波（SH）场中，可在46nm厚的超薄范德华平台上生成无背景的SH涡旋光束。利用3R-MoS₂的C₃ᵥ对称性，研究实现了单片式全光开关，能以亚光周期精度在具有相反拓扑电荷（l=±1）类厄米-高斯与拉盖尔-高斯涡旋SH光束之间切换。该研究确立了人工3R-MoS₂晶体作为纳米级非线性结构光生成与全光重构的单片平台，为集成经典与量子光子技术推进有源纳米光子源。
英文摘要
The orbital angular momentum (OAM) of light is a discrete, unbounded degree of freedom that underpins mode-multiplexed communications and high-dimensional quantum photonics. Yet, dynamic OAM control remains dependent on bulky free-space optics or cascaded architectures that separate switching from wavefront shaping, hindering nanoscale integration. Here, we engineer artificial van der Waals crystals from rhombohedrally stacked (3R) MoS$_2$, in which spatial control of the local crystal orientation imprints a nonlinear geometric phase onto the second-harmonic (SH) field, enabling background-free generation of SH vortex beams in an ultrathin (46 nm) van der Waals platform. Leveraging the C$_{3v}$ symmetry of 3R-MoS$_2$, we demonstrate monolithic, all-optical switching with sub-optical-cycle precision between Hermite-Gauss-like and Laguerre-Gaussian vortex SH beams with opposite topological charges ($l=\pm1$). Our results establish artificial 3R-MoS$_2$ crystals as a monolithic platform for the generation and all-optical reconfiguration of nonlinear structured light at the nanoscale, advancing active nanophotonic sources for integrated classical and quantum photonic technologies.
