We show that when strongly focusing a linearly polarized optical vortex with the topological charge 2, in the near-focus region, there occurs not only a reverse energy flow (where the projection of the Pointing vector is negative) but the right-handed circular polarization of light as well. Notably, thanks to spin–orbital conversion the on-axis polarization vector handedness is the same as that of the transverse energy flow, i.e. anticlockwise. An absorbing spherical microparticle centered on the optical axis placed in the focus may be expected to rotate anticlockwise around its axis and its center of masses. Theoretical predictions are corroborated by the numerical simulation.

中文翻译：

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聚焦涡旋激光束并将线性偏振转换为圆偏振

我们表明，当强聚焦具有拓扑电荷 2 的线偏振光涡流时，在近焦区域，不仅会发生反向能量流（指向矢量的投影为负），还会发生右手圆偏振光也是如此。值得注意的是，由于自旋轨道转换，轴上极化矢量旋向与横向能量流的旋向相同，即逆时针方向。可以预期以光轴为中心的吸收性球形微粒会围绕其轴和质心逆时针旋转。数值模拟证实了理论预测。