Geng Tao, Li Min, Guo Hanming
Opt Express. 2021 Apr 26;29(9):14069-14077. doi: 10.1364/OE.423027.
We theoretically study the propagation properties of the vector circular Airy vortex beam in detail. The results show that the orbital angular momentum can induce a localized spin angular momentum after autofocusing in the paraxial regime, which leads to an abrupt polarization transition just before the focal plane. However, there is no angular momentum conversion from orbital angular momentum to spin angular momentum during the whole propagation process. We provide an intuitive explanation for the appearance of such spin angular momentum localization. This investigation is expected to advance our understanding of the vector properties of circular Airy beam and optical spin-orbit coupling.
我们从理论上详细研究了矢量圆形艾里涡旋光束的传播特性。结果表明，在傍轴区域自聚焦后，轨道角动量可诱导出局部自旋角动量，这导致在焦平面之前出现突然的偏振转变。然而，在整个传播过程中不存在从轨道角动量到自旋角动量的角动量转换。我们对这种自旋角动量局域化的出现给出了直观解释。这项研究有望增进我们对圆形艾里光束的矢量特性和光学自旋 - 轨道耦合的理解。
