Spin-orbit Hall effect in the tight focusing of a radially polarized vortex beam

When the first-order radially polarized vortex beam propagates in an uniaxial crystal, the spin and the orbital angular momentum parts can be separated. It is called the optical spin-orbit Hall effect. In this study, we investigate the tight focusing of the radially polarized vortex beam theoretically and find the spatial separation of the spin and the orbital angular momentum parts occurs in the focal plane when the polarization order equals 1 and the vortex charge equals 1 (or -1). Moreover, when the initial phase of the polarization state takes pi/2, the spatial separation of intensity in the focal plane corresponds to the spatial separation of the spin and the orbital angular momentum parts. This phenomenon can be considered as a manifestation of the optical spin-orbit Hall effect in the tight focusing of radially polarized vortex beam. Also, we show that, when the polarization order is greater than 1, the initial phase change of polarization state just leads to the rotation of the focal field and the spin and the orbital angular momentum density in the focal plane. Our results provide the potential application in the field of optical micro-manipulation. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Automated summary

In this study, we investigated the tight focusing of a radially polarized vortex beam and found that the spatial separation of the spin and the orbital angular momentum parts can occur in the focal plane. This phenomenon, known as the optical spin-orbit Hall effect, has potential applications in optical micro-manipulation. Additionally, we observed that changes in the initial phase of the polarization state only lead to the rotation of the focal field and the spin and the orbital angular momentum density in the focal plane when the polarization order is greater than 1.