Focusing Properties of Radially Polarized Partially Coherent Gaussian Vortex Array Beams

In this study, the radially polarized partially coherent Gaussian vortex array (RPPCGVA) beam is constructed by introducing the multiple off-axis vortex phase into the center of each sub-lobe of partially coherent Gaussian array beam, and the focusing properties of the beam through a thin lens are investigated. The experimental results show that the RPPCGVA beams with different numbers of vortex arrays will gradually merge from the initial array beam into a single beam in the focus process due to its spatial correlation between the sub-beams, and present polygonal hollow, flat-top, and Gaussian-like distributions in the focal plane, respectively. In addition, the polarization state of the beam is gradually transformed from the initial radial polarization into an inverted triangle, oblique square, pentagon, etc. elliptical polarization distribution due to the effect of multiple off-axis vortex phases. However, the beam's intensity degrades to Gaussian distribution, and its polarization state degrades to an elliptical polarization distribution with circular symmetry when the coherence is very low. In addition, the beam still has strong self-healing ability when one of the sub-beams is partially blocked by a sectoral obstacle, but it will be destroyed for completely blocking, resulting in a distortion for the intensity and its state of polarization.