AI 中文总结
该研究针对现有扭转范德华异质结研究忽略自然缺陷的问题，通过定制界面二次谐波相位梯度，实现了拓扑可配置的非线性涡旋产生，为量子非线性光学等领域提供了可重构的非线性结构光产生平台。
AI 中文摘要
范德华（vdW）材料为纳米尺度的非线性光学和量子光学提供了高度可调且高效的平台。扭转堆叠的vdW异质结可实现对对称性和层间耦合的精准控制。现有研究主要聚焦于平面扭转界面，却忽略了此类vdW异质结中自然形成且不可避免的缺陷。在此，我们展示了利用vdW异质结的角奇点实现拓扑可配置的非线性涡旋产生，从而开展非线性奇异光学研究。通过在每个界面定制方位角离散的二次谐波相位梯度，我们获得了可编程的非线性涡旋发射器，其具有主导的目标轨道角动量（OAM）分量。实验上分别实现了拓扑电荷ℓ=1和ℓ=-2的非线性OAM光束。我们的工作挖掘了扭转vdW材料中非线性奇异光学的未开发潜力，将其作为一种可重构且无需光刻的平台，用于产生非线性结构光，在量子非线性光学及相关领域具有重要意义。
英文摘要
van der Waals (vdW) materials offer a highly tunable and efficient platform at nanoscale for nonlinear and quantum optics. Twist-stacked vdW heterostructures enable elegant control of symmetry and interlayer coupling. Prior studies mainly focus on planar twisted interfaces, while neglecting the naturally formed and mandatory defects in such vdW heterostructures. Here, we demonstrate nonlinear singular optics with topologically configurable nonlinear vortex generation at the corner singularity of vdW heterostructures. By tailoring azimuthally discrete second-harmonic phase gradients at each interface, we obtain programmable nonlinear vortex emitters with dominant target OAM components. Nonlinear OAM beams with topological charge $\ell = 1$ and $\ell = -2$ are experimentally realized, respectively. Our work unlocks the untapped potentials of nonlinear singular optics in twisted vdW materials as a reconfigurable and lithography-free platform for nonlinear structured light generation, important in quantum nonlinear optics and related fields.
