Experimental generation and orbital angular momentum properties of focused field for vector vortex beams on Hybrid-order Poincare sphere

Due to the anisotropic spatial polarization state and spiral phase distribution, the orbital angular momentum (OAM) of vector vortex beams (VVBs) has attracted increasingly attention in recent years. In this paper, the Hybrid-order Poincare sphere VVBs are constructed by orthogonal left-handed (L-H) and right-handed (R-H) circularly polarized vortexes. The vector vortex light fields of different orders at the focal plane are collected and analyzed experimentally. Based on the vector diffraction integral theory, the effects of the topological charge and polarization order for VVBs, as well as the initial phase difference for L-H and R-H components on the OAM properties of focused field for the longitudinal component are investigated numerically. It is found that the OAM density distribution of the longitudinal component shows inner and outer two layers on the whole, and the layers mainly concentrate the corresponding L-H and R-H components respectively. Meanwhile, the signs of the topological charges for L-H and R-H components determine the positive and negative distributions of the inner and outer OAM density respectively. When the initial phase difference of L-H and R-H components 00 changes in the range of 0-2x, the OAM density rotates the angle 00/2 along the clockwise. However, the OAM of the longitudinal component does not change with 00, and increases as the polarization order m increases when the topological charge of VVBs I > 2. The results could be helpful to further explore the applications of the OAM for VVBs in the fields of optical detection and communication.