A spatiotemporal optical vortex (STOV) is an intrinsic optical orbital angular momentum (OAM) structure in which the OAM vector is orthogonal to the propagation direction [Optica 6, 1547 (2019) [CrossRef] ] and the optical phase circulates in space-time. Here, we experimentally and theoretically demonstrate the generation of the second harmonic of a STOV-carrying pulse along with the conservation of STOV-based OAM. Our experiments verify that photons can have intrinsic orbital angular momentum perpendicular to their propagation direction.

中文翻译：

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时空光学涡旋的二次谐波产生和轨道角动量守恒

时空光学涡旋（STOV）是一种固有的光学轨道角动量（OAM）的结构，其中所述OAM向量是正交的传播方向[。光学6，1547（2019）[交叉引用] ]和在空间-时间的光学相位循环。在这里，我们通过实验和理论上证明了带STOV的脉冲的二次谐波的产生以及基于STOV的OAM的守恒。我们的实验证明，光子可以具有垂直于其传播方向的固有轨道角动量。