Origin of Experimental Realization of Vector Beams by Superposition Technique: Geometric Phase

Optical vector beam generation based on the superposition technique [Phys. Rev. Lett. 107(5), 053601 (2011)] has attracted significant interest in both fundamental and applied optics due to its simplicity and cost-effectiveness. In this approach, the superposed modes exist in orthogonal polarization states and therefore do not interfere with each other. When optical gadgets are employed for characterization, the corresponding polarization distribution can be observed. In this work, we report that the characteristic (non-uniform) polarization distribution of vector beams is not inherently present in their field distribution. Instead, the observed polarization features arise during characterization as a consequence of the geometric phase difference introduced between the superposed modes by the optical gadgets. This analysis opens a new direction in the understanding of various classes of vector beams and offers potential advances in the field of structured beam optics.